W h y i s

STITCH-AND-GLFE BOATBUILDING SO POPULAR?

Any num ber of construction m ethods will produce a beautiful boat. But for the backyard builder with lim ited experience and a tight budget, the choice is not so complicated. Traditional plank-on-frame and cold-molded construction require com plicated lofting and building molds—to say nothing of expensive tooling and lots of time. Stitch-and-glue construction, on the o ther hand, can produce the same results with a substantial sa ngs in time and money. The process is quicker, easier, uses fewer parts, and produces a boat that is m uch easier to m aintain—without the building molds and with only the simplest lofting. For tools, you need little m ore than a circular saw, a sander/po lisher/g rinder, a block plane, a framing square, a level, and a tape measure.

Sam Devlin has elevated stitch-and-glue boatbuilding to an artform, and his graceful design', have attracted the attention of backyard builders across the country. H ere is all you need to know to build the boat of your dreams, w hether it’s a 7-foot dinghy or a 40-foot power cruiser. Devlin's Boatbuilding: How to Build Any Boat the Stitch-and-Glue Way shares the wisdom of his 18 years of experience designing, building, and helping others build his fleet o f small sail- and powerboats.

It’s all here, from choosing a design and setting up shop to painting the finished hull and launching. T here is also a gallery of Devlin’s designs and a detailed appendix listing sources for tools and o ther materials.

Front and Back Cover Photographs by Marty Loken Cover Design by Dan Kirchoff

D e v l i n ’ s

B o a t b u i l d i n g

D e v l i n ’ s

B o a t b u il d in g

How t o B u i l d A n y b o a t

THE STITCH -A N D -G LU E WAY

S a m u a l D e v l i n

Published by International Marine^

10 9 8 7 6

Copyright © 1996 International Marine'*, a division o f The McGraw-Hill Companies. All rights reserved. The publisher takes no responsibility for the use o f any o f the materials o r methods described in this book, nor for the products thereof.

Printed in the United States o f America.

Library o f Congress Cataloging-in-Publication Data

Devlin, Samual.[Boatbuilding]Devlin s boatbuilding: how to build any boat the stitch and glue

way / Samual Devlin p. cm.

Includes indexISBN 0-07-157990-7 (alk. paper)1. Boatbuilding. 2. Wooden boats— Design and construction.

Questions regarding the content o f this book should be addressed to:

International Marine P.O. Box 220 Camden, ME 04843

Questions regarding the ordering o f this book should be addressed to:

The McGraw-Hill Companies Customer Service Department P.O. Box 547 Blacklick, OH 43004 Retail customers: 1-800-262-4729 Bookstores: 1-800-722-4726

Devlin’s Boatbuilding is printed on acid-tree paper.

Printed by Q uebecor Printing, Fairfield, PADesign and Production b) Dan KirchoffEdited by Jonathan Eaton, Ted Hugger, Tom McCarthy

The name “International Marine’ and the International Marine logo are trademarks of The McGraw-Hill Companies.

International Marine/ Ragged Mountain Press

A Division of The McGraw-Hill Companies

I. Title.VM351.D48 1995 623.8'2023—dc20

95-39678CIP

De d i c a t i o n

T h ere is no road m ap a d ream er can fol­low to becom e a b o a t designer and wooden boat builder. You ju st have to keep your pilot light o f inspiration shielded, and recognize w hen th e flames o f creativity need to be expressed. T h e world sends many ill winds to blow ou t the light. Money is probably the chief one; figuring out how to m ake m oney bu ild ing w ooden boats rem ains one o f th e m ost difficult chal­lenges o f all. T he necessary evils o f taxes, licenses, bureaucracies, and, today, all the req u ired ecological perm its constitu te another. A nd finally, strange as it seems, to m ake a living designing and build ing w ooden boats you n eed to sell your cre­ations—m arket them and indeed stand by them fo r an in o rd in a te am o u n t o f tim e. Many customers have only a sketchy under­standing o f what efforts it takes to design and build boats for a living.

With these pitfalls besetting my career, I have found th a t I am only as good as the people around me. So I must give thanks to my parents for allowing me enough adver­sity in life to toughen my hide, and enough

nurturing to inspire m e to keep going.To my wife, Liz, who has shared my

dream s for all these years, struggling side by side with m e so th a t we could live o u r lives the way we wanted. O ur lives today are the results o f our own labors, and it’s been a strange and wonderful path.

To the workers who have stood by my side, lived with my many moods, and kept perspective on th e dream . Especiallyjim H enson, Randy Foster, and Joel Mill.

To my many customers, who with their hard-earned m oney allowed m e to follow my dream , an d who had th e p a tience to wait for their boats.

A nd in no small part, to a w orld o f in teresting an d insp iring boats. To m e, boats are like fine wine o r music: They live in th e hearts o f designers, builders, and owners. They can elevate o u r spirits to a h igher plane. If I can accomplish one thing in life itwould be to have elevated som eone else’s spirits with my own creations.

Thank you all for the privilege o f a few moments.

C o n t e n t s

Dedication....................................................................... vIntroduction: The Magic o f Boats............................... ixC hapter 1. The Advantages o f

Stitch-and-Glue Boatbuilding ....1C hapter 2. Setting U p S h o p ....................................7Chapter 3. Selecting a Suitable Design...............19Chapter 4. Selecting Marine Plywood

and Dimensional Lum ber........21Chapter 5. Epoxy Systems...................................... 29Chapter 6. Fiberglass Cloth and T a p e ................39C hapter 7. Scarfing................................................. 45C hapter 8. Lofting....................................................51C hapter 9. M odeling............................................... 55C hapter 10. Scantlings.............................................70C hapter 11. Building Cradles.................................79C hapter 12. Stitching Up the H ull........................83Chapter 13. Bulkheads, Clamps,

and Floor Tim bers..................... 92C hapter 14. Filleting and Glassing

Plywood Joints........................... 109C hapter 15. Rolling Over the H u l l .................... 117C hapter 16. Removing W ires............................... 121C hapter 17. Cold Molding

the Stitch-and-Glue H u ll........123C hapter 18. Keels, Rudders, Skegs,

and O th er A ppendages.......... 127Chapter 19. Sheathing the Exterior................... 130

C hapter 20. Sanding and Fairing........................134Chapter 21. Marking the Waterline

and Painting the B o tto m .......137Chapter 22. Righting the H u ll ............................ 140Chapter 23. In terior Structures........................... 141C hapter 24. Painting .............................................. 150Chapter 25. Exterior Trim and H ardw are........160Chapter 26. Propulsion..........................................163Chapter 27. L aunching..........................................166Chapter 28. R epairs ............................................... 168Appendices

A. Devlin’s D esigns..................171B. List o f Suppliers.................. 187

Index .......................................................................... 192

I n t r o d u c t i o n :

Th e m a g i c o f B o a t s

Have you ever considered building a boat? Have you wondered whether the dream of m aking a boat fo r yourself was attainable? For m e, th e re is always a m agic to boat­building. It starts with little m ore than the rig h t d ream an d the rig h t m otivation. W hen I begin to consider build ing a new boat, I usually im agine som e beautiful place on the water. I sense the fresh wind in my face, the w arm th o f th e sunshine, and try to im agine how the boat handles and moves. Surely there is no o ther advan­tage to the exercise than the power o f the dream to get going. But that advantage is a huge one; th e tools an d m aterials are im portant, bu t it’s the dream that sees you through to the end o f the project.

Few things are m ore satisfying than crafting a pile o f rough wood in to a beau­tiful, graceful boat. I t is a soul-satisfying psychological and physical adventure. For m e it is the essence of creative expression, and anyone can benefit from it. It is so o ften h ard to derive lasting satisfaction from o u r jobs. T h e hours w ould seem shorter and the stress m ore m anageable if we could m ore often see what we’re accom­plishing. Well, a boat is a living structu re th a t reflects the b u ild er an d his o r h e r spirit. As it takes shape you can stand back an d survey it with p ride , an d see w hat you’ve created with your own hands.

B uild ing your own boat will be an em otional roller-coaster ride; your energy level and enthusiasm will soar to astound­ing heights, and ju s t as quickly, p lum m et to fr ig h ten in g depths. K eeping this p h e ­n o m en o n in perspective is critical from the start, because you’ll have days w hen you gravely d o u b t the w orth o f the whole project. Take advantage o f the low points in your enthusiasm by turn ing your atten­tion to som ething else for a few days. You can then re tu rn refreshed and motivated. But d o n ’t go away fo r too long; you may lose in tere st in the p ro jec t altogether. Learn to pace yourself.

Finally, strive to keep things u n d e r control. I have always kept in m ind that the boat I was building would have to be sold someday. You should do this, too—even if selling your pride-and-joy is the fu rthest th ing from your m ind. I t ’s all too easy to spend too m uch m oney an d time on a given stage in the building process. If you keep in perspective the b o a t’s salability, you’re m ore likely to set realistic limits on the actual costs and labor involved. If you think o f this boat as the first and only boat you will ever m ake, you’re likely to mis­manage the whole project. You’ll have cost overruns, an d you will find yourself bogged down by an obsessive desire to have everything perfect. Set specific time

IX

I n t r o d u c t i o n

and budget constraints, and hold to them as you move through the building process.

You may be wondering w hether build­ing a boat is w ithin your capabilities. I haven’t a doubt: With the right dream , the right design, and the right motivation, any­one can build a wonderful boat. W hat fol­lows is my attem pt to explain th e stitch-

and-glue m eth o d o f boatbuild ing . It is readily approachab le . B ring only your dream s and your enthusiasm . T he boat you build will strengthen and reflect your in n e r spirit, an d like m e you m ight find that designing and building wooden boats is a fine thing to do with o n e ’s life.

x

Th e A d v a n t a g e s o f

STITCH-AND-GliUE BOATBUILDING

T he differences betw een conventional plywood-on-frame and stitch-and-glue con­struction are significant. To bette r under­stand the differences betw een the two, contrast the structur al dissimilarities of an early b ip lane and a m o d ern je t airliner. T he b iplane was m ade up o f fram es and spars over which was stretched a thin skin. T he j e t a ir l in e r’s s tructu re , on the o th e r hand, is m uch simpler, with a stressed alu­m inum skin rigidly attached to bulkheads an d spars to create a single unit. A boat built by a ttach ing plywood p lank ing to lum ber frames is m ost sim ilar to the b iplane; a stitch-and-glue boat m ore closely resembles the je t airliner—a hom o­geneous structure in which the skin bears the primary stresses.

The basic argum ent for stitch-and-glue construction is that it uses fewer parts and that epoxy is used to bond and seal the parts to achieve a stronger, m onocoque (one- piece) boat. T he initial construc tion is qu icker an d easier, uses fewer parts, an d requires no building molds. And in the long term, the boat is m uch easier to maintain.

L ooking back over my own develop­m ent in boatbuilding, and considering the

advantages and disadvantages o f the many forms of construction I ’ve used, 1 find my m em ory foggy as to why I chose one form over another. In the beginning, I was sim­ply working out the differences and iden­tifying the problem s of each form of con­struction. I knew that working with natural wood products was appealing, and I knew I wanted to use wood products in an ecolog­ically sound manner. A boat built o f wood has a spirit that is easy to see and feel, bu t m uch harder to define.

Almost all boatbu ild ing m ethods requ ire expensive tooling. P roduction fiberglass boats have their elaborate plugs and molds. Traditional plank-on-frame or cold-m olded w ooden boats require com­plicated build ing molds. This expensive tooling generally stops m uch of the evo­lution of an individual boat design. Stitch- and-glue construction does not bear this initial burden. With no building molds or tooling to consider, a stitch-and-glue design has a chance to constantly evolve and im prove— an d th a t’s im portan t. I believe tha t any design can use refine­ment, and as my work has evolved, I have found ways to increase the ability o f the

1

T h e A d v a n t a g e s o f S t i t c h - a n d - G l v e B o a t b i ' i l d i n g

stitch-and-glue b o a t to suit its purpose an d m eet its ow ner’s p erfo rm an ce requirem ents.

W hen I began to get serious about boatbuilding, my first hurd le was finding shop space and lin ing up the necessary tools. T here seemed to be no way to avoid these expenses, an d ju s t as surely, no way to be efficient w ithout them . T here was a great tem ptation to toss away all my ideas about innovative boatbuilding and stick to the traditional small wooden boats, which need ed fewer pow er tools. I know that shop space, the cost o f tools, and o th e r financial concerns shaped and form ed my earliest choices in boatbuilding. With less initial investment, I could have built tradi­tional skiffs an d respectab le , small wooden, plank-on-frame boats, although I

was intim idated by my lack o f skills in the beginning. But in h indsight, these influ ­ences were beneficial, as access to bu ild ­ing materials and a gradual accum ulation o f quality tools indirectly steered me to the stitch-and-glue construction format.

W hen I began building boats, m arine plywood was readily available in a variety of thicknesses, an d in lengths up to 16 feet. It was during these early years that I began wiring together plywood panels and re in ­forcing the jo in ts and seams with epoxy. I was totally unaware of others using similar m ethods, an d it was only la te r th a t I dis­covered similar technologies were in use in Australia, New Zealand, and Europe. Little was ever written o r published abou t such efforts, and in retrospect, I ’m glad I d idn ’t know ab o u t them . I was free to work ou t

D e v l i n ’ s B o a t b u i l d i n g

T h e A d v a n t a g e s o f S t i t c h - a n d - G l u e B o a t b u i l d i n g

Figure 1-3. The author rows a 17-foot 2-inch Oarling on Seattle’s Lake Union.

my own assumptions and refine my m eth­ods in isolation, un in fluenced by o th ers’ prejudices. Maybe the greatest conse­quence o f th a t experience was th a t it forced me to develop my own style, and I constantly worked toward new and in te r­esting designs.

At first, I simply w anted to work in wood an d natu ra l p roducts. I w anted to have good-looking, sturdy boats. I wanted a

boatbu ild ing m ethod th a t would be rela­tively inexpensive. The m ore I worked with plywood, wiring, an d epoxies, the m ore convinced I becam e th a t stitch-and-glue boats could be bu ilt s tro n g er an d easier, and would require less m aintenance than o ther boatbuilding methods.

But I was also a ided by the econom y and by circumstances that were much big­ger in scope and im portance than a young

Figure 1-4. A 22-foot Surf Scoter awaits another season of cruising on Puget Sound.

4

D e v l i n ’s B o a t b u i l d i n g

m an ’s w anting to build w ooden boats for a living. A lthough creative, ingenious pio­neers h ad in tro d u ced the techn iques of mass production to w ooden boatbuilding at several points in the 20di century, it was the advent and pro liferation o f fiberglass boatbu ild ing th a t in tro d u ced mass-pro- duction possibilities to a host o f builders. “B oatbuild ing” alm ost tu rn ed in to boat assembly, and almost became extinct in the process.

But the expense o f tooling for a fiber­glass b o a t allows only an occasional and restricted journey from inspiration to final product, and floods the m arket with simi­lar-looking boats. As time went by, in spite of the mass production o f fiberglass boats, a growing segm ent o f the boating public

started to search for an alternative, creat­ing a niche m arket that clamored for inno­vative design, m odern m aterials technol­ogy, and better-built boats. In the early days o f my career, the fact th a t my boats were wooden was an im pedim ent to selling them . But th e re have b een som e real shake-ups in the p ro d u c tio n glass boat market. Today, the experienced consum er realizes that fiberglass boats will n o t last forever, an d that they have th e ir own unique faults and shortcomings. Gradually, w ood/epoxy composite boats have picked up a distinct m arketing advantage as buy­ers becom e better inform ed and less influ­enced by slick advertising and flashy show­room models.

A nother great thing about stitch-and-

Figure 1-5. A 24-foot 6-inch Black Crown, with inboard diesel engine, slowly motors about on Lake Union.

T h e A d v a n t a g e s o f S t i t c h - a n d - C l u e B o a t b u i l d i n g

glue building is that you can get by with a m in im um o f tools. You need little m ore th an a c ircu lar saw, a s a n d e r /p o lis h e r / grinder, a block plane, a fram ing square, a level, and a tape measure. With these sim­ple and inexpensive tools you can build a lot o f boat. T he most basic stitch-and-glue boat simply requires cutting plywood pan­els, stitching the panels together, and then fiberglassing the seams with epoxy. W hen the seams have cured, you pull the wires, sheathe the exterior with epoxy and fiber­glass cloth, and use the sander-polisher to smooth out the edges. With the addition of seats and gunwale re in forcem ent, you’re ready for pain t and finishing work. I t’s no m ore complicated than that.

Do n o t allow yourself to be p u t off by

the m isconception that it’s hard to build a stitch-and-glue boat. I t’s no harder and no m ore complicated than building a garden shed. T h ere are n o molds, and th e re are few pre lim inary steps, since you begin immediately to set up the hull. With stitch- and-glue construction, there is no need for the shipwright skills o f trad itional boat­building m ethods. At the same time there is enough dep th to the m edium that even the most experienced boatbuilder can find satisfaction. Plywood is easy to work with, an d a forgiving m aterial. It utilizes all o f w ood’s strengths, while m inim izing its weaknesses. Since th e re is no n eed fo r com plicated fram ing, you will be amazed by the simplicity and speed o f bu ild ing a stitch-and-glue boat.

6

S e t t i n g U p S h o p

Figure 2-1. The 29-foot Means o f Grace design under construction at the Devlin shop.

allow en o u g h room to walk com fortably a ro u n d the assembly p rocedures. If your garage o r workspace is too small for the b o a t’s dim ensions, find a n o th e r space or tem porarily en large your build ing to accom m odate th e project. Remember, depending upon its size, your boat can take a considerable time to build and will tie up your garage o r o ther valuable workspace.

G ood work requ ires am ple lighting, and a well-lit shop is a safe shop. To protect

YOl U W O R K S H O P

You need a dry, sheltered workshop to build your boat. Look a t the full d im ensions— length, width, and height—of the boat you in ten d to build . Using those dim ensions, imagine the rough outline o f the boat and its m ajor com ponen ts on th e shop floor. Add a m inim um of th ree feet to all sides to

7

S e t t i n g U p S h o p

tools, prevent the wood stock from warp­ing, an d p ro m o te p ro p e r curing o f the epoxy, you’ll need a dry shop. If you d o n ’t have an enclosed work area, th e re is a greater chance that your work will no t cure properly o r th a t excessive m oisture will becom e trapped in the wood and eventu­ally weaken the structu re . E lim inate the hassle factors; it takes time to set up before you begin each work session. You’ll want to get to work quickly and easily and be able to work in short blocks o f time. Some o f my best work is done in well-motivated spurts.

H ea t is far m ore im p o rtan t th an you m ight think. M odern epoxies dem and cur­ing tim e, an d the sh o rte r th a t tim e, the better. T he w arm er the w orkshop, the shorter the cure times. Delayed cure times

can lead to contam ination, dust, or insects fouling the surfaces. Your own com fort is im portan t, too. Warm hands work b e tte r than cold hands, and if you are com fort­able, your patience an d attitude will be more attuned to the work at hand.

Your workspace shou ld have am ple room for your tools, and its layout should be conducive to easy cleaning. Cutting, sanding, and m any o th e r steps o f boat­bu ild ing create a g reat deal o f dust. It is m andato ry to clean o ften— in fact every evening— to avoid kicking up dust during the critical stages of epoxy use and pain t­ing. Get into the habit o f constantly clean­ing and picking up after yourself.

I often live with my tools in less-than- ldeal conditions. I like my tools in well-

Figure 2-2. Workbench and storage area shows a bit o f the typical boatshop clutter.

8

D e v l i n ’ s B o a t b u i l d i n g

organized storage cabinets o r s to red on easily visible wall racks. A sturdy work­ben ch is an ind ispensable tool, with two vises to double-clamp long stock. While we are d ream ing here , the workspace could have a wood stove fo r b u rn ing up scraps, and a stereo to soothe the soul. T he m ore com fortable and homelike your shop, the g rea ter the chances you’ll choose an evening of boatbuilding over an evening in front o f the television set. But bear in mind that you must be realistic about your time and energy, and the shop is a means to an end, no t an end in itself. I would ra ther get going on a boat project in a less-than-ideal shop than be hopelessly m ired in the quest for a perfect workspace.

TOOLS

T he avid boatbuilder will find no lim it to the tools available, and no bottom in the wishing well. T em per what you want with what you truly need, and then pare the list to what you can afford.

T he most fundam ental advice is this: Spend good m oney on good tools. Avoid buying p o o re r grades o f tools, and wait

longer, if you m ust, to buy good quality. Professional-grade tools balance better, ru n sm oother, last m uch longer, and are m ore enjoyable to use. T he better the tool, the m ore likely you are to achieve high lev­els o f craftsm anship. If you are spending hard-earned money on the best boatbuild­ing materials, why not use the best tools on those materials?

Your initial list o f tools can be as sim­ple o r com plex as you choose. An ade­quate collection can be quite small, since stitch-and-glue construc tion requires an absolute m inim um o f tools.

T he first consideration is w hether you prefer hand o r power tools. Your costs will be less if you choose h an d tools, bu t your work will be m uch slower. O f course there are several pow er tools you’ll find absolutely indispensable.

Sander

The most used and abused power tool in my shop is a M akita #9207 sander-polisher. I consider a sander-polisher a real m ust— even for the small builder—to create a uni­form ly finished boat. This slightly sm aller

Figure 2-3. The workhorses of the sanding department, from left: the Makita 9207 disc sander, Porter-Cable Random orbital sander, cmd Makita palm sander.

9

S e t t i n g U p S h o p

version o f a metal grinder is lighter and runs a t slower speeds (1,500 to 3,200 rp m ), an im portan t consideration for boatbuilding. It can turn slowly enough to hold the sand­paper and it w on’t burn wood as quickly as the larger, faster metal grinders. Used with a soft sanding pad and 8-inch, 3M Stickit (or equivalent) disc sandpaper, the Makita will easily handle all your basic sanding needs.

Block Plane

Every boatbuilder should have a good block plane. My fa ther always had a simple-look­ing block plane in his workshop, and when I began boatbuild ing , I was convinced I could do better. So motivated, I headed off to the nearest hardw are store with its vast selection o f tools. I looked at everything from simple low-angle block planes like my fa th e r’s to w onderfully specialized and complex tools. I selected the most compli- cated-looking and expensive m odel, com­p lete with all the bells and whistles. It had adjustments and little levers for every imag­inable need, and I was sure this block plane would cut wood better than anything I had ever held in my hands before. As soon as I re tu rn ed hom e, I sh arp en ed the factory edge an d placed a beautifu l, straight-

g ra ined piece o f yellow cedar in a bench vise. In my m in d ’s eye, I could already see the long, sm ooth curls o f shavings peeling off the block o f wood. But what a rude awak­ening. T he plane iron to re into the wood, digging in with every stroke. I sh o rten ed the blade depth and tried again. Now it sim­ply choked the slot between the blade and the body of the plane with wood chips—still no smooth shavings. No m atter what I tried, this m arvelous p lane would n o t p roduce acceptable results. It seem ed to have been designed by a fiend to gouge and m angle wood. F rustrated an d chastened , with my tail betw een my legs, I w ent back to the hardw are store an d picked o u t a block plane ju s t like my Dad’s.

I have never found a block plane bet­ter than the Stanley #118, which I bought that day on my second try. It is the perfect low-angle block p lane for fin ishing ply­wood edges and doing all basic boat con­struction planing. Stay away from the bells an d whistles. T h e Stanley #118 does the jo b and is all the builder really needs.

Power Saws

T h ere is a vast array o f pow er saws from which to choose, including h an d h e ld jig ­

Figure 2-4. One o f the simplest and finest hand tools available to the boat­builder: the Stanley #118 low-angle block plane.

1 0

D e v l i n ’ s B o a t b u i l d i n g

saws, saber saws, circu lar saws, handsaws, and various table saws.

A jigsaw can double as a scroll saw and a p o o r m an ’s bandsaw. I have fo u n d the Bosch #1581 to be a fine tool with suffi­cient blade adjustments to allow quick cut­ting and multiple angles and bevels.

You’ll need a circular saw to cut ply­wood panels. With a carbide-tipped blade, the circular saw will even cut large-radius curves in plywood. Buy a 7/4-inch m odel to work with thicker stock, ra th e r than a 6%-inch.

1 cut my teeth on my Dad’s old heavy- duty worm-drive Skilsaw. It was an expen­sive tool, and when the time came to pur­chase my own, th e tem ptation to cut corners was im possible to resist. My new saw was a direct-drive sidew inder type, with the blade set on the right-hand side o f th e housing. To use it, because I ’m righ t-handed, I h ad to lean over the saw

to view th e cut line. This p u t my eyes in line with the dust blowing up from the cut a n d m ade it nearly im possible to cu t a s traigh t line. Som etim es the saw would b ind an d rip itself ou t o f the cut with fr ig h ten in g force. So, ju s t as I had with the h an d p lane, I finally w ent o u t and spent my hard-earned m oney on a proper worm-drive saw.

Bandsaw

W hile it is no t an absolute necessity, after y ou’ve w orked on your p ro jec t awhile you’ll find yourself waking in the middle o f the night longing for a bandsaw. And once you’ve used one, you won t be able to imagine how you ever lived without it.

I have a Powermatic 14-inch bandsaw, an d i t ’s a real beaut. T hese saws d o n ’t seem to be as com m on as som e o f the Rockwell o r D elta m odels, bu t for my

Figure 2-5. A worm-drive Skilsaw, left, and the Bosch #1581 jigsaw.

S e t t i n g U p S h o p

Figure 2-6. A pair o f Milwaukee Magnum Holeshooters. (Note the epoxy buildup on the left one, an often-used tool.)

money, there is no b e tte r bandsaw on the m arket. I buy a bandsaw based on the blade guides m ore than any o ther feature. Good bearing-type blade guides ensure an easier, m ore precise cut.

Table Saw

A table saw can be an o th e r valuable asset in your shop. I have a Rockwell Unisaw; although a fine tool, it has an appetite for starter capacitors—at about $75 a pop. But this saw cuts s trong and straight. Buy a heavy saw with as big a m otor as possible. I haven’t found horsepow er to be an issue with bandsaws, bu t with table saws, horse­power is cutting power.

Good blades can make or break a table saw, so buy carbide-toothed blades with as m any tee th as possible. Also n o te th a t there are different types o f blades fo r dif­ferent cuts—buy a good crosscut blade for plywood work an d a good rip b lade fo r resawing dim ensional wood.

Drill

A good power drill is a m ust for stitch-and- glue construction, and I have found that the //-inch M agnum Holeshooter, m ade by M ilwaukee Tool Company, is the best o f the many choices. It is nicely balanced and will handle every job . Along with the drill motor, buy a drill index, with bit sizes from Yu, to 'A inch in increm ents of J4 inch. I p re ­fer high-speed, steel twist bits for general work, b u t I have also used brad-point bits with good results. T he latter are designed especially fo r wood and fo r b o rin g flat- b o ttom ed holes. T he b rad-poin t bits are rarely available in anyth ing b u t full sets and are quite expensive, but are worth the investment.

Hammer

Every boatbuilder needs a hammer. I keep a light ham m er—preferably a 13-ounce— for delicate work, an d a 16- to 20-ounce

I 2

D e v l i n ’ s B o a t b u i l d i n g

ham m er fo r heavier pound ing . Vaughan m anufactures the nicest ham m ers in these w eight ranges. Look fo r good balance, p referably w ooden handles, an d fine m achining on the heads. And try to avoid pulling out large, deeply driven nails with a w ooden-handled ham m er; you’ll likely sis n o t break it. Use a prybar or a crowbar.

Sharpening Stone

Keep a good sharpening stone handy. The planes, chisels, knives, and o th e r blades used in b oatbu ild ing all need constant a tten tio n to function properly. R ather than send ing them out fo r sharpen ing , learn to care for your blades yourself.

T here are many stones available, bu t I m uch prefer the diamond-type, which has a metallic-looking, hole-filled face glued to a chunk o f plastic. Small d iam ond grains are em bedded in the m etal face, and the holes allow th e m inu te sh arp en in g residues to free themselves from the sur­face. This is the m ost versatile o f sharpen­ing stones; DMT makes the best o f these. Water, usually th e reco m m en d ed lubri­cant, rusts the stones quickly, so I use a light oil such as WD-40 instead. Kerosene also works. I m o u n ted the stone on my w orkbench with screws to keep it from moving around , and have m ade a box lid to keep shop dust from fouling its face.

Speaking o f sharpening tools, it’s nice to have a stropping leather to remove the bu rr after a workout on the stone. I keep a 24-inch fin ished-leather strop handy, and know from experience that a couple o f swipes on it does wonders for any cut­ting edge. Actually, any o ld finished- lea th e r belt will doub le as a fine strop, and its buckle makes a handy fastener for belaying one end while stropping.

Other Tools

Find a good pair o f pliers. Large lineman- type pliers are the best fo r cu tting and twisting the wire you’re going to use. Buy the 9-inch size with a wire cutter built into the side of the jaws. I t’s im portan t to find a pair o f pliers that feels com fortable in your hands, since you’ll be using them a g reat deal in the wiring process. This is a top-priority tool.

You’ll n eed a small knife fo r m yriad tasks. For years I used a Swiss Army knife, b u t afte r d ro p p in g yet an o th e r in to the briny deep, I dec ided to search for a bet­te r alternative. I finally settled on a good rigging knife. This companion-on-my-hip had to be durab le and ho ld a good edge, yet com pact en o u g h to fit my h an d per­fectly. I had a g rea t knife m ade by A drienne Rice o f M adrona Knives, Route 1, Box 1230, Lopez Island, W ashington, 98261. I t’s small enough to avoid th a t Daniel Boone look, and it’s great no t hav­ing to fish around in my pocket for a fold­ing knife.

You’ll need a framing square for draw­ing the station lines d u rin g the lofting process. A simple L-square with inch gra­dations, o r a 50-inch drywall T-square is adequate , a lthough any size can be used along with battens to ex tend the station lines. I find th a t a straight, stiff, 50-inch w ooden b a tten with a sim ple fram ing square is all I really need.

Pick up a re trac tin g tape m easure at least 25 feet long. T he Stanley Powermatic is ju s t the ticket. Its inch-wide b lade will ex ten d 10 feet o r so an d rem ain straight while unsupported . You will do a lot of chine-to-chine and sheer-to-sheer measur­ing to tru e up the hull. O ne h int: Take care that you slow the blade when retract-

13

S e t t i n g U p S h u p

D e v l i n ' s B o a t b u i l d i n g

ing it in to the case. I have seen the ends b reak off as a result o f high-speed retrac­tion. I have never found folding rulers to be o f m uch use, so to my m ind , they are better left o u t of your active toolbox.

You’ll need a good compass. Buy one that has 10- or 12-inch legs and allows you to insert a pencil. You’ll rely on your com­pass for scribing the bulkheads and for fit­ting various b o a t parts. Try a used-tool dealer, since the best compasses are the o lder models. An alternative m ight be to buy a set o f dividers an d tape a pencil to one leg, a lth o u g h you’ll need to re tape each time you sharpen the pencil.

To keep things straight and level, add a plum b bob, a chalkline, and a 2- or 3-foot level to your toolbox. I use my plum b bob for truing up the bulkheads and maintain­ing the vertical alignm ent o f the hull dur­ing construc tion o f the larger boats. T h e re ’s also a new electronic tool on the m arke t called the Smartlevel. A lthough

there is a bit of a learning curve to use one o f these, once mastered, it is a true joy.

G et a p a ir o f scissors to cut o u t card ­board o r p ap e r patterns, fiberglass cloth and tape, and peel ply. Look for heavy-duty shears ra th e r th an light sewing scissors. Some m igh t find it easier to use a razor b lade o r utility knife w hen cu tting fiber­glass tape.

A well-fitted dust resp ira to r is an im portant tool that should be part o f your basic kit. Your boatbuilding career will be a very sho rt one if you d o n ’t take care of your lungs. W hile I may n o t be able to afford a dust collector for my shop, I can certainly afford to spend $35 fo r a good organic vapor canister respirator. W e’ve tried m any types in o u r shop over the years, and the current favorite is a 3M 6000 series— an affordable, lightweight, and com fortable dust mask. It com es e ither with twist-on cartridges o r with ligh ter weight twist-on prefilters. I clean my face-

VFigure 2-8. A full-face-mask respirator for spray pain ting left, and a canister filter respirator:

1 5

S e t t i n g U p S h v p

piece in the dishw asher every week and replace prefilters at the sam e time. T he face mask is $12.65, with a pack o f two pre­filters for $4.35; cartridges are $11.45.

O n e o f the m ost visible differences between professionally built and amateur- built boats is the detail in the finishwork. T hat m eans shaped moldings, cham fered edges, and rounded corners on the boat’s wood trim. A router will give you the ability to mill a variety o f shaped wood parts. I rely on a heavy-duty, 3-hp Makita #3612BR ro u te r m o u n ted on a base bo lted to the table o f my table saw. For handwork, I use a smaller Porter-Cable, m odel 1001.

A nother nice-to-have tool is a jitterbug or vibrating sander, invaluable for smooth­ing surfaces prior to painting and varnish­

ing. I use a Makita B04510, and, due to the dem ands o f my shop, keep several spares in reserve. R andom orb it sanders are an o th e r excellen t choice. I have several Porter-Cable 333s in the shop, and these have worked very well.

T h ere are m any o th e r tools th a t can greatly ease building b u t are certainly not required. Those worthy o f special m ention include a surface p laner and an air com ­pressor. If your b u d g e t will no t stretch , rem em ber that you can always ren t them. Start small with a m in im um o f tools, and if boatbuild ing grows on you, so will your tool inventory.

I will spare you the full dissertation, but I have found some o f my best tools at garage sales and flea markets. Look fo r specialty-

Figure 2-9. A router setup on a tablesaw base is a versatile option to a fixed shaper.

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D e v l i n ' s B o a t b u i l d i n g

tool buyers in your area. They have experi­ence and provide the best advice about the variety and quality o f each tool. I have been thoroughly deligh ted by finds (in som e cases, alm ost steals) a t used-tool dealers. T here are also tool reconditioners who spe­cialize in o ld er stationary pow er tools, which a re s tu rd ie r— often heavier cast iron—and promise longer service than the newer, lightw eight models. S hopping the alternative tool m arket is good fun and well w orth th e time; ju s t d o n ’t le t it in te rfe re with your boatbuilding time.

Basic Tool List (Amateur Builder)

Sander-polisher: Makita #9207 SPC, variable speed (1,500 to 3,200 rpm ), 3M 8-inch soft backing pad, 3M Stickit sanding discs o f 80- and 150-grit (8-inch diameter)

Block plane: Stanley #118 Jigsaw Bosch #1581VS Orbital Action Circular saw: Skil m odel 77 (13-amp

m otor) o r Black and Decker 714-i rich worm-drive

Drill: Milwaukee 0234-1 Magnum Holeshooter, J4-inch, 5.4-amp,0 to 850 rpm

Drill bit index: Vm- to Ki-inch high-speed steel bits

Hammer: Vaughan, 13- and 20-ounce sizes

Pliers: 9-inch Crescent #2050-9C, line­m an’s type with side cutters

Tape measure: Stanley #33-425 Powerlock, 25-foot

Vibrating sander: Makita B04510 palm sander or Porter-Cable 333 random- orbit finish sander

Sharpening stones: diam ond type, DMT (325 coarse grit for general work, 600 fine grit, 220 extra-coarse grit)

Square: 24-inch fram ing square or

48-inch drywall T-square Compass: 8-inch loose-leg dividers Bevel gauge: 8-inch metal Plumb bob: 6- o r 8-oz.Level. Smartlevel electronic level or

spirit-bubble type, 24- o r 36-inch Chalkline: Stanley 50-foot Rigging o r pocket knife 3M 6000 series respirator w /organic

prefilters Safety glassesTransparent water hose: 30 feet of

!4-inch o r %-inch (for water leveling hull)

Handsaw: Japanese dozuki with crosscut and rip blades

Scissors: 8- to 10-inch blades H andheld propane torch with fuel

cartridges Miscellaneous screwdrivers Sawhorses: at least two, 24 inches high Surgical gloves: for working with epoxy

Prices o f the above item s approxim ately$650

Additional Tools and Materials

Waterless hand st>ap (e.g. Fast O range): to remove epoxy, o r automotive hand cleaner

Tongue depressors o r stirring sticks Autobody plastic squeegees: for

spreading thickened epoxy Disposable mixing cups: graduated

13- to 16-ounce, for mixing epoxy and hardener

o r

M inipumps o r gear pum ps for dispens­ing and m easuring epoxy and hardener

Steel baling wire: two rolls for wiring up hulls (If boat is over 16 feet, sub­stitute 14-gauge electric fence wire.)

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S e t t i n g U p S h o p

Sandpaper: 80-, 150-, and 220-grit Shop vacuum (optional)Pencils: twoBattens: %-inch x %-inch x 16 feet, and

/'/-inch x )4-inch x 10 feet Router with '/>- and X-inch carbide

roundover bits (optional)Parrot-peak wire-cutter pliers: Rnipex

KN6801, 8-inch

Advanced Tools

Bandsaw: 14-inch Table saw: 10-inchWood planer: 12-inch, M akita#2012

Power Feed with 12-amp m otor Disc belt sander: Delta 31-730 6 x 48-inch

belt and 12-inch-disc finishing m achine

Cutoff saw: 10-inch, Makita LSI 030 Drill press: Delta 11-990 12-inch bench

model Air compressor

HVLP (high velocity, low pressure) spray gun for painting

DrawknifeCordless drill: Panasonic EY6205BC 12-

volt, heavy-duty, J4-inch, with keyless chuck

Orbital sanderH and power plane: Makita #1900B

(3)4 inch)Wood rasps Plug cutters M echanic’s wrenches Sledgehammer: short-handled Jointer: 6-inch or larger Compressed air stapler: SENCO

LN4450, drives %-inch wide crown staples, up to 1-inch long.

Shop workbench and vise Cold chisel set Punches and nail sets Ball peen ham m er

18

S e l e c t i n g

a S u i t a b l e De s i g n

If this is your first boatbuilding project, it is wise to begin with a small, sim ple boat. B uilding confidence an d skill is m ore im p o rtan t th an bu ild ing th e boat itself. Many boatbu ilders have u n d er ta k en too large a project, only to stall o u t o r totally abandon the effort. Materials can exceed $6 p e r p o u n d o f a b o a t’s dry weight, and the weight o f the boat increases exponen­tially with its length . Cost overruns can quickly and fatally affect the ou tcom e of the project. Labor, too, increases expo ­nentially with size. Build big if you must, but be sure to consider all the ramifica­tions, including the additional equipment.

O nce you have developed your boat­b u ild ing skills on sm aller boats, you can move on to bigger boats with confidence and a healthy dose o f experience tucked away in your toolbox.

W hen selecting a boat design, con ­sider w he ther the b o a t will be trailered , w hether you will need winter storage, and where you will keep it during the sum m er months. Imagine how you’ll use your boat, including your perform ance and com fort expectations. To understand the dynamics o f a boat, study the hull form. T hink o f a

pendulum ; the deeper the hull, the longer and slower the hull will swing. Conversely, the shallower the hull, the sho rte r and faster the swing. A boat’s stability depends directly on the width and uepth of its hull.

D o n ’t scrim p on b lueprin ts an d the cost of plans, as this will certainly frustrate your results. A good set o f plans is like a road m ap, guid ing you step by step th rough your boatbuild ing journey. Poor

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S e l e c t i n g a S u i t a b l e D e s i g n

plans will almost certainly assure that you’ll lose your way. Look fo r a classical, clean design, one with what I refer to as a “boat­like” look. Try to avoid designs th a t a ttem p t to m ake a silk purse from sows’ ears o r cram the accommodations o f a 35- footer in to a 25-foot hull.

Think carefully about how you will use the boat. W atch how boats move th rough the water; you’ll becom e adept in the m en­tal process o f c ritiqu ing and d iscerning proper boat design. There should be a right feel abou t the design, even in your im agi­nation . W h ether a bo a t has conventional sheer o r straight sheer, w hether it has one shape o r another, you can develop an edu ­cated sense abou t its balance and p ro p o r­tion. L earn to trust your instincts as your boat sense evolves, and help the process by read ing m agazines and books an d by observing all types o f boats on your water­ways.

Boatbuilding can and should be a life­tim e process, so i t ’s never too late to get started. I started as a young boy, observing boats with my Dad a t boat shows. W e’d am ble up an d down the aisles, stopp ing only w hen a special boat w ould catch o u r eye and dem and closer appraisal. My young and un tu to red eye would force m e to stop and dwell on a boat th a t looked pleasing and just righ t to m e. Soon, I could sense th a t certa in “boat-like” look, an d could imagine how a particular boat would move in the water, and why it m ight give its owner great satisfaction and pride.

I spent my ch ildhood in O re g o n ’s W illamette Valley, and there saw the won­derful McKenzie River drift boats and the graceful b u t rugged coastal dories. These boats were highly evolved fo r th e ir p u r­

poses: fishing on w hitew ater rivers o r p u n ch in g over tu rb u len t coastal su rf to fish the Pacific. Although they had under­gone m any evolutionary changes, these boats were always built o f plywood.

To my young eyes, these were beautiful shapes to behold. T he drift boat had a strong sheer and extremely rockered bottom.

T he coastal dories plied those treach ­erous waters, where the bays were accessible only by passage th ro u g h rough su rf and over dangerous sandbars. Heavily influ ­en ced by the d rift boats, the dories were designed with extrem e sheer and sufficient rise in the bow to tackle the rough surf and b ar conditions. It daw ned on me, at some early point, that rough water is unforgiving o f eccentric design and poorly constructed boats. So the characteristics I sought from my earliest observations were great strength in the sheer an d an overall design that would handle the roughest conditions.

Since those early years my designs have been a mix o f self-induced and com­missioned inspiration, ranging from 7-foot 6-inch dinghies to 42-foot sailboats and 43- foo t pow erboats. All are stitch-and-glue, and all share the com m on heritage of com­ing from my heart.

I’m often told that my boats are m uch different in real life from the way they look in th e ir drawings, an d I ’m n o t sure w hether th a t’s an insult to my drafting o r a com plim ent to the spirit o f the boat. I'll h an g on to the th o u g h t th a t i t ’s a reflec­tion o f the b o a t’s spirit, honestly ea rn ed through the inspiration o f its designer and th e labors o f its builders. Any boat th a t’s honest in its origin—sweated over, at times bled on, and often cursed at—can be one o f the sweetest pieces o f art going.

20

S e l e c t i n g Ma r i n e P l y w o o d

a n d D i m e n s i o n a l L u m b e r

M A R I N E P L Y W O O D

Since stitch-and-glue boats are built o f ply­wood, you’ll need to know what quality of plywood to buy, how to ju d g e th a t quality to ensu re a first-rate boat, and w here to locate top grades. Look for marine plywood th a t m eets th e British 1088 standard o r American “AA” rating. Do your looking at a m arine lum beryard that offers accurate inform ation, fair pricing, and a reputation fo r quality in b o th m arine plywood and dim ensional lumber. Very likely you’ll have to order by phone; look for sources in the boatbuilding magazines and in the List of Suppliers in the appendix.

T here can be no compromise: the ply­w ood must be m arine grade. Plywood m eant fo r house construc tion is m uch m ore susceptible to w ater and structura l degradation. Sooner o r later, non-m arine plywood will fail in som e m anner. You’ll quickly spend th e few dollars you’ve saved—and m uch m ore—when it’s time to repair o r replace the cheaper plywood.

T he A m erican system o f grad ing ply­

wood uses letters to designate th e panel type. An “AA” designation indicates that the p an e l’s two outside faces are the best grade, o r “A” quality. In Am erican grades o f m arine panels, the in te rio r plies m ust also m eet certain criteria, such as the solid­ity o f the veneers and uniform ity o f species. This is im portant, since domestic m arine plywood veneers can have fir, larch, or hem lock in their in terior layers. The fir and larch are desirable, bu t stay away from hem lock—it is ne ither stable n o r durable enough for m arine use.

I ’m p re jud iced toward foreign ply­woods that m eet at least the BS 1088 stan­dard; the Am erican grading system allows fo r too m uch in the way o f defects and voids within the in terior veneers. To pu t it simply, if you want your boat to last twenty years o r m ore, you had b e tte r use im ported m arine plywood.

This issue o f using im ported m arine plywood was no t so easily resolved. In the early years o f my b oatbu ild ing career, I used a lot o f domestic fir m arine plywood. O ften , on a cool m orn ing while walking o u t to the shop, I w ould no tice the dew on the sides o f a boa t th a t was being

21

S e l e c t i n g M a r i n e P l y w o o d a n d D i m e n s i o n a l L u m b e r

stored in the yard. A lthough m ost of the b o a t’s side w ould be covered with dew, there would be several small, elliptical dry areas in a ran d o m p atte rn . They were shaped exactly like the repair patches I ’d often noticed on the faces of the plywood. O ne day, I drilled a hole in one such dry area and discovered that, lo and behold, it was actually a void in the in terio r plies of the wood.

You can probably guess that it wasn’t too easy to drill holes in each o f the dry spots on that boat to inject epoxy into the voids. Yet, if these holes o r voids a re n ’t properly filled and sealed, you’re ju s t ask­ing for m oisture to work its way in to the in terio r o f the plywood and begin its das­tardly work o f swelling th e w ood fiber, delam inating the plies, and even perm it­ting ro t to set in.

You will pay fo r cheap plywood many times over. We once construc ted two 19- foo t W in ter W ren Class sailboats side by side using the same epoxy, the same glass cloth, and the same work crew. O ne boat was bu ilt o f less expensive fir m arine ply­wood, the o th e r o f very expensive im ported m arine plywood from H olland. As it happened, both boats were launched the same day, and both cam e back to our shop for refinishing during the same sum­m er season ab o u t fo u r years later. Both were repainted, revarnished, and checked very carefully for any poten tial problem s. T he inexpensive fir plywood boat had only one defect, a gouge w here th e o u tboard engine, being raised ou t of the water, had h it th e transom edge. T h e o th e r boat showed no problems.

W hen bo th jobs w ere com pleted , I noticed som ething strange about the two work bills. T he bill fo r the first boat, the W inter W ren bu ilt with th e fir plywood,

ind icated $46 m ore in m aterials cost and alm ost double th e labo r for its refit. T he added m aterial expense was in two areas, san d p ap er an d a small am o u n t o f epoxy, the la tte r used fo r th e transom -edge fix. Why double the labor and why m ore sand­paper used in the job? Answer: the fir ply­wood was nowhere near as sm ooth and fair as th e D utch plywood, an d it simply req u ired m ore extensive sanding and preparation for repainting.

T he ow ner o f the boat built with the p rem ium -grade plywood had sp en t an add itional $900 fo r th e D utch plywood, but he saved m ore than $600 in labor for the first m ajor refit o f his boat. T h at sav­ings, if you consider th a t h e w ould refit at least every four years, would m ore than pay for the expensive plywood by the boat’s sixth year. In addition, the beautiful grain o f th e m ore expensive plywood allowed m e to varnish the whole in terior o f the boat, while th e fir plywood boat had to be p a in ted because o f surface imperfections.

O f th e im p o rted m arine plywoods, I com m only use th ree species o f African m ahogany—khaya, sapele, an d okoum e. All th ree are available in a variety o f thick­nesses an d all are suitable fo r use in a m arine env ironm ent. H ull panels, bulk­heads, and decks can all be built with these plywoods. Okoume, which is a salmon-pink color, is the lightest in weight and the least strong of the mahoganies, bu t I often use it as the base o f my stitch-and-glue hulls. Khaya and sapele are bo th a b it heavier and show up a m uch d ark er co lor when epoxy-sealed. Sapele’s grain pattern is par­ticularly beautiful and can make for spec­tacular brightwork when varnished.

Because quality stitch-and-glue boat construc tion depends on top-grade

z z

%

D e v l i n ’ s B o a t b u i l d i n g

m arine plywood, I often test plywood stock w hen it arrives at my shop (especially if it com es from a new o r d iffe ren t m anufac­tu rer) . I cu t 4-inch squares from sam ple sheets and boil them for 20 to 30 m inutes in a small pan. T hen I take them directly from the boiling water and place them in the freezer. When they have frozen solid, I boil them again, repeating this cycle three times. If your plywood can withstand this test, it will probably last a long time.

You m igh t also dry the test pieces in the oven to m ore closely simulate what will happen to plywood when it’s part of a boat in service. Boats experience wild swings of tem pera tu re and undergo cycles o f soak­ing and drying. They are trailered over ho t highways, launched in to cold water, then hau led and d ried o u t once again. Keep this constan t p u n ish m en t in m ind w hen you select your m aterials, especially the plywood.

Although epoxies are wonderful prod­ucts that have made m odern wooden boats an economical possibility, they aren ’t quite the m iracle workers some people believe. An epoxy-sealed and encapsulated boat is only as good as the m ateria l it was built from. Epoxy cannot atone for an inherent weakness in the wood

C hecking— fine cracks in the face o f the plywood— allows moisture to en te r the plywood laminate. It is the greatest enemy of m arine plywood and the biggest liabil­ity of plywood boat construction. Checking is m ost com m on in fir plywood, usually appearing as small cracks running length­wise along the g ra in o f the wood. Checking, and its attendant problems, may be the result o f the plywood m anufactur­ing process. Fir logs are thoroughly soaked and steamed before the veneering process, w here rotary cutters peel the log's layers,

forcing its curved surfaces to suddenly lie flat. T hat stress may manifest itself later as cracks.

This checking p rob lem can persist even th rough epoxy sealing and fiber­glass/epoxy sheathing. Individual veneers and glue lines in the plywood may restrict the m oisture p rob lem to local areas, but even isolated areas are subject to swelling and contraction, and ultimately, to delam­ination and failure. It is persistent enough to alm ost convince me against ever using fir m arine plywood in my boats.

O ne final com m ent abou t plywood Rot requ ires th ree things to flourish. It m ust have a food source (which the wood eagerly supplies), oxygen (which is already presen t within the wood cells), and mois­ture. M oisture is the elem ent most within o u r control. Lesser grades o f plywood can have internal voids that can act like straws, drawing moisture to the interior. Any kind o f break in the veneer, sealant, or sheath­ing— no m atte r how small—will act as a straw sucking in m oisture from outside. While you are assembling your stitch-and- glue boat, vigilantly inspect the plywood edges fo r voids o r em pty spaces o f any type. And always be sure to seal all plywood edges and surfaces with epoxy to ensure maximum longevity and help prevent mois­ture invasion and veneer degradation.

DIMENSIONAL LUM BEE

There are many com ponents on the stitch- and-glue boat that requ ire d im ensional (non-plywood) lum ber—gunwales, skegs, keels, breasthooks, and seat thwarts, for example. A larger boat may call for dim en­sional lum ber fo r sheer clamps, rubrails, sheerstrakes, bowsprits, masts, boom s, deck beams, tillers, and cheekblocks.

23

S e l e c t i n g M a r i n e P l \ w o o d a n d D i m e n s i o n a l L u m b e r

T h ere are two classifications for dry dim ensional wood: air-dried and kiln-dried. I t is im perative in any s truc tu re th a t will be encapsulated and sealed with epoxy (as in a stitch-and-glue boat) th a t all wood used be as dry as possible before sealing. Air-dried wood is usually better and easier to w ork with because the h igh tem pera ­tures o f the kiln-drying process can rob the wood o f suppleness and strength. You will find th a t the kiln-dried is h a rd e r and can be m ore brittle, a distinct disadvantage in boatbuild ing . O n the o th e r h an d , eco­nom ics may dictate the use o f kiln-dried, since it is usually less expensive, and m ore universally available than air-dried lumber.

Air-drying wood requires patience; the wood needs approxim ately one year per inch o f thickness to dry fully. D uring this lengthy process, m uch care must be taken to avoid warping or cupping, and the wood m ust be constantly m o n ito red to p ro tec t against invading insects. Most lumberyards simply do n ’t trouble themselves with stock­ing air-dried woods.

Furtherm ore, small lumberyards tend no t to have a good selection of exotic hard­woods, usually confining the bulk o f their dim ensional stock to domestic softwoods. While softwoods may be useful for certain parts of your boat, you will still need to find a source o f hardw oods for o th e r parts. D epending on your locale, you m ight have some excellent indigenous hardwoods, no t to m ention softwoods. Research the wood technology texts to find which local woods are durable and stable enough to m ake good boatbuilding materials. H ere in the Northwest, we have a lo t o f Douglas fir (a softw ood), w hich is stable, durab le , and can be used for almost any part o f the boat from keel to mast. The problem, though, is that most o f the best clear, virgin-growth fir

is being exported to foreign markets as fast as it can be logged.

Investigate the boatbu ild ing m aga­zines fo r lum beryards th a t specialize in boatbu ild ing woods. Indeed , these yards may be your best bet, since tu rn ing to an expert is always the way to avoid confusion and eliminate the costly errors o f using the wrong type o r grade o f wood. Any lum ber dealer th a t advertises in a national maga­zine sells mail-order.

Always look for clear-grained wood, because knots and defects create u n to ld problems. O ften, dim ensional wood stock will be bright finished (varnished) and vis­ible on the finished boat. Clear stock will make your build ing jo b m uch easier, and will result in less waste.

Especially if it is kiln-dried, look for lengthwise cracks and for any discoloring, w hich m igh t ind icate in c ip ien t decay. W hen you’re buying mail-order, be specific as to your expectations. W hen you w ant clear stock, m ake sure the order-taker understands this.

Be sure to no te the grain o f the wood—flat, vertical, o r mixed. “Flat grain”

Figure 4-1. Wood grains.

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D e v l i n ' s B o a t b u i l d i n g

Figure 4-2. Cutting a flat-grained board to produce vertical-grained pieces.

m eans that the grain lines are parallel to the wide face o f the board. In a vertically grained board the grain lines are p erp en ­d icu lar to th e wide face. In d im ensional lu m b er o f square cross section, you can convert flat g ra in to vertical simply by ro ta tin g th e p iece 90 degrees. If you are b en d in g gunwales with a cross section of Vi x VA inches on a small boat, a gunwale with a vertical grain will be harder to bend, b u t stiffer and stronger. A flat- o r mixed- g rain gunwale w ould b en d easier, bu t won’t be nearly as strong. And, when mak­ing a sheer clamp on a larger boat, where m ultiple layers o f dim ensional wood must be lam inated to form th e clam p, flat- g ra ined wood will b en d in to p lace m ore readily, fasten easier, and do so without as m uch splitting.

In the grand old-growth forests o f our g rea t-g ran d fa th ers’ tim es the trees were cu t e igh t to ten feet from th e g ro u n d to avoid the burls, b u tt growth, an d o th e r irregu larities at th e ir bases. O ften there was twisted grain at the base due to weight compression and o ther natural causes, and bu ilders realized early on th a t w hen this

wood at the base was d ried , it ten d ed to crack, twist, and warp. But big trees were plentiful, so they simply igno red the bot­tom of the log. Today, loggers cut as flush to the ground as possible to maximize tree footage, and butt- o r twisted-grain woods often end up in lum beryard stock.

To d e tec t grain problem s, sight the length o f the board, and if the grain slants ou t to the edge of the piece, you have grain runout. If it is pronounced, you can assume it is from a butt-cut log and it may be a very unstab le p iece o f wood. O nce g lued in to the boat these pieces will be m ore prone to cracks and jo in t failures that can be nearly impossible to repair. Use the same criteria for selecting dimensional lum ber as you use fo r selecting m arine plywood: Look for quality, accurate lum beryard inform ation, and fair pricing, bu t expect to pay a goodly am ount for good stock.

W ood Types

Douglas Fir. Readily available, fir is light in color with a slightly reddish tone and a long, straight grain. It is light in weight rel­ative to its streng th . For o u r purposes, it takes a fine finish and can be easily glued. You will find fir th e best w ood fo r keels, stringers, and clamps. It is also suitable for masts and spars.

Spruce. T here are still vast forests o f clear, old-growth spruce being harvested, espe­cially in Canada and Alaska—most notably, Sitka spruce. Spruce is absolutely the best w ood fo r masts, boom s, gaffs, and bowsprits. T he m ajor advantages o f spruce are its light weight and extrem e inter-grain strength. Spruce’s b lond color is similar to Douglas fir bu t no t as reddish. W hen epoxy­sealed, sp ruce tends to yellow qu ite a bit.

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S e l e c t i n g M a r i n e P l y w o o d a n d D i m e n s i o n a l L u m b e r

runout straight

Figure 4-4. Grain runout, left, may indicate an unstable piece of lumber.

F or consistency o f color, you m ust take great care to seal the wood evenly.

For spars, you will need long, straight- g ra ined pieces o f spruce, preferab ly air- dried . If you use kiln-dried spruce, check that the drying was consistent and the wood is un ifo rm in dryness an d appearance. If you foresee that your build ing project will stretch over a long period, buy partially air- dried o r green wood and carefully regulate its final drying, allowing the wood to stabi­lize while the building project is underway.

Mahogany. M ahogany is used extensively in boatbuild ing . T he best available to us

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D e v l i n ’ s B o a t b u i l d i n g

these days is H onduras m ahogany from C entra l America. A durab le , beautifu l hardw ood with dark red co lor and a dis­tinctive grain that takes a bright, clear fin­ish, m ahogany will never frustrate you. It glues superbly, seals well, and is always worth its prem ium price.

Also worth considering are the darker African khaya m ahogany, an d okoum e, a salm on-pink m ahogany th a t is also from Africa. Khaya an d okoum e are the m ain species used fo r high-grade E uropean m arine plywood.

Lauan m ahogany (and its relatives) is available in a range o f colors from red to pink. It is technically n o t a true m ahogany but is m ore closely related to the cedar fam­ily. Its grain is quite fine an d it works won­derfully with hand tools. In the U.S. market, lum beryards usually stock lauan from the Philippines o r Indonesia. This m ahogany is recognizable by its speckled grain with a base co lor o f red d ish brown. Use the darker, denser varieties. T here is also a sub­species o f lauan m ahogany called m er- anti— the most durable lauan available.

Watch for wind shakes o r jagged lines and cracks across the grain, in lauans espe­cially. These defects can be traced to log­ging practices th a t allow trees to fall over each other, an d to clear-cutting, which eliminates protection from extrem e tropi­cal storm s. I t ’s easy to miss these defects until th e p iece has b een m illed and is in place on the boat, so watch carefully.

Teak. Teak is a great wood for exterior sur­faces, particularly rubrails, sheer guards, handrails, toerails, decks, and seat thwarts. Teak is heavy an d d u rab le and will w ith­stand m ore abuse and neglect than almost any o th e r wood. I t is a dark chocolate- brown wood, with a beautifu l and p ro ­

n o u n ced grain . I never use anything bu t teak fo r toerails an d rubrails, an d these p arts rarely get an epoxy-sealed an d var­nished finish on my boats. Instead, I apply several coats o f teak oil annually, afte r a scrubbing to remove mold o r moss growth. If the toerail o r rubrail is dam aged slightly, the oil finish allows me to sm ooth ou t the dam age with a b lock p lane an d a b it o f sandpaper. A light coat o f teak oil restores the finish without missing a beat.

A fairly recent arrival on the market is Cetol, a teak finish by the Sikkens C om pany th a t you apply m uch like a var­nish. Its co lor on th e first app lica tion is sort o f a startling orange, but it blends well with the teak’s natural color after a couple o f coats. Cetol is durab le , and easy to touch-up an d m ain tain— im p o rtan t con­cerns in my shop.

T h o u g h teak is very f orgiving as well as handsom e an d workable, no wood is m aintenance-free. In the Northwest I see a lto g e th e r too m any neg lected teak sur­faces on boats, w hich take on a silvery appearance an d o ften a grow th o f g reen moss. I t ’s so sim ple to scrub teak with a m ild bleach and water solution that there is really no excuse fo r ignoring it as much as often happens.

In the interior, you might use teak for trim, the fiddles, cleat stock, and the floor­boards. Because it is dark, however, teak is easy to overuse. Too m uch teak m akes a dank and som ber interior, and will quickly add a lot o f weight to the boat. Its greatest drawback, however, is th a t it simply does n o t glue well. W hen you fasten teak, p re ­pare ad jo in ing surfaces for snug fits and wipe down with acetone and a clean rag to rem ove the n a tu ra l oils before applying epoxy glues o r polysulfide adhesives such as Sikaflex o r 3M 5200. T hen , w hen you

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S e l e c t i n g M a r i n e P l y w o o d a n d D i m e n s i o n a l L u m b e r

m ate the surfaces, use plenty o f m echani­cal fasteners such as screws or bolts.

Yellow Cedar. Two species o f yellow cedar are popular boatbuilding woods. Both are lightweight and have good strength. These woods hold m echanical fasteners well and have excellent durability. My preference is P ort O rfo rd cedar. A native o f the Northwest, it has a honey-blond color and a sweet, pungen t smell that I never tire of while working it. Durable and rot-resistant, it glues well, takes a finish readily, and like fir, has many uses. Virtually any part of the boat cou ld be bu ilt from P o rt O rfo rd cedar. In boatbu ild ing heaven, I ’d m ake boats of Port O rford cedar plywood.

Alaskan yellow cedar has similar quali­ties b u t its arom a is m ore pungen t, o ften rem in d in g m e of ju n ip e r berries. Both Port O rford and Alaskan yellow cedar are m embers of the cypress family and have all the desirable characteristics o f cypress: durability, good g luing ability, an d high strength-to-weight ratios.

Oak. W hite oak is a hardw ood that runs beige to nut-brown in color. It is m edium to heavy in weight, has high strength, and is potentially durable—though sometimes I have seen this wood ro t with frightening speed. I th in k its tendency to ro t may be related to the season of harvest. Oak h ar­vested during the spring, w hen the sap is flowing a t its m axim um , seems to have a m uch g reater tendency to rot. If d ie tree is harvested in the fall or winter, when the sap is down, I would wager th a t the wood m ight last forever.

White oak is used in areas o f the boat w here ex trem e s tren g th is needed . Gunwale clamps and rubrails are the two

m ost usual places. I favor this wood for tillers, which need to be as strong as possi­ble. The glueability o f white oak has been questioned, bu t I have never had any trou­ble. As with teak, i t’s best to wipe down w hite oak with ace tone an d a clean rag before gluing, and m echanical fasteners should be used to assist the bond to o ther surfaces.

Red oak possesses m any o f the same physical characteristics as w hite oak— although it isn ’t as du rab le— an d has the sam e kinds o f uses on a boat. It has a h igher cell porosity and is thus m ore pen­etrable by liquid than white oak, so it may be somewhat m ore susceptible to decay.

T here is an old adage I keep in m ind when selecting oak. When examining a pile, i f you find, even one piece o f wood uith rot in it, avoid the lot!

Specialty Woods. Specialty woods may be used on any boat, particularly to decorate and to highlight customized interior work. My advice is to lim it the variety o f woods, using no m ore than fou r o r five types per boat, an d always consider how well the wood will glue; if you are in doub t be sure to add m echanical fasteners.

A long with th e finest grades o f im ported m arine plywood, I prefer fir gun­wales an d clamps, H o nduras m ahogany floo r tim bers, deck beam s, an d in te rio r trim, spruce spars, oak for tillers, and teak for exterior guards and trim. My concern fo r design simplicity leads m e to caution against too many d ifferent woods: Simple is often better. And for heaven’s sake, d o n ’t fool with th e natu ra l co lor o f th e wood. S taining dim inishes th e w ood’s ability to seal with epoxy, and the natural color God gave the wood is always the best one.

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E p o x y S y s t e m s

E P O X Y R E S I N A N D

H A R D E N E R

While stitch-and-glue boat construction was possible before epoxy, the developm ent o f these adhesives has m ade possible the bu ild in g o f larger boats o f m uch h ig h er quality and greater strength. Before epoxy, the re inforced jo in ts had to be m ade with layers o f fiberglass clo th an d polyester resin. Most o f the boats m ade with polyester resins w ere dinghy-sized and had to be taken out o f the water when not in use. The b o n d in g characteristics o f the polyester resin was lim ited greatly by the skills o f the builder, an d the durab ility o f the b o a t depended heavily on proper maintenance. If those early boats were left to soak o r were abused, the plywood quickly absorbed w ater an d swelled. W hen d ried out, the wood shrank, and after a lot o f those cycles the resins w ould release th e ir bo n d to the wood— and as a consequence, m any early boats suffered from resin /c lo th failures.

W hen epoxy use in boat construction cam e o n to the scene in the 1970s, its

g rea ter streng th and durability op en ed a wide range o f new possibilities. Boats could be m ade m uch larger. They could be left in the water w ithout fear o f absorbing water, and a stitch-and-glue boat’s life expectancy increased trem endously. C oncerns fo r m ain tenance were greatly reduced, while structural integrity was greatly enhanced.

Epoxy is a m ultipurpose m aterial for boatbuilding. It is used as a coating to seal all o f the plywood and dim ensional wood surfaces, and as a g lue fo r the structu ral joints. It can be m ixed with wood flour o r o th e r fillers to m ake strong structural fil­lets. Epoxy is also used with fiberglass cloth to re in fo rce seams an d shea the ex te rio r surfaces, giving us a s trong w ate rp roo f structure.

Because o f its chem ical m akeup, epoxy offers distinct advantages to poly­ester resin. First, it is a m uch stronger adhesive. Second, it has far su p erio r sec­ondary b o n d in g characteristics (the abil­ity to stick to w ood o r a previously cured epoxy o r polyester surface). And third, it is a superior m oisture barrier.

O n the down side, epoxy requires g re a te r p recision w hen m ixing the resin

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E p o x y S y s t e m s

and hardener, it can be toxic if improperly used, and lastly, it is m ore expensive.

Epoxy is a two-part adhesive. T he resin com ponen t is a clear, syrupy liquid, while the hardener is thicker (more viscous) and usually the co lor o f honey. These liqu id resins and hardeners must be mixed using the exact ra tio specified by the m anufac­turer. This ratio will differ greatly from one system to another, so be sure to follow the m an u fac tu re r’s d irections precisely. Beware that a deviation of as little as five percent in either direction can underm ine the final physical properties o f the cured epoxy. And once you have m ixed the liq­uids in the correct ratio, they must be fully and thoroughly stirred , scraping th e sur­faces of the mixing container and moving all the liquids around until you are sure of a com plete blend.

W hen mixed, the epoxy undergoes an exotherm ic reaction, generating heat as it cures. As this reaction occurs, th e liquid thickens and becomes a solid. A m bient air tem peratu re affects the speed with which the epoxy sets up, or, as I say in my shop, goes off. T h e optim al tem p era tu re for epoxy is a round 75°F. T he lower the tem ­perature, the slower the cure.

To counter this effect, epoxy manufac­turers form ulate various “speeds” o f hard ­eners. In the Northwest, w here tem pera ­tures stay fairly m odera te , I use a fast hardener through most of the year, switch­ing to a slower form ulation in the two o r three warmest months. T he resin formula­tion fo r boatbu ild ing is always the same; only the h a rd e n e r co m p o n en t varies. If you should choose to use a fast h a rd en e r on days above 80°F, be p rep a red to work fast and mix small batches.

It is n o t uncom m on to have a con ­tainer of epoxy smoke o r even “flash off.”

W hen a batch o f epoxy overheats in your container, remove it from your workspace immediately. Use caution: T he epoxy can becom e h o t en o u g h to m elt th e plastic mixing container! And d o n ’t b reathe the fumes if the epoxy has begun to flash.

If I find the epoxy flashing off, o r boil­ing, I m ix sm aller am ounts o r switch to a slower hardener. Pouring the batch in to a larger, flat co n ta in e r can help dissipate heat and slow the rate of cure also.

U nder average conditions, the epoxy takes 24 hours to reach an easily sandable state, bu t again, this varies with tem pera ­ture. In the sum m er, when tem peratu res range betw een 80° and 90°F, I have been able to epoxy a small project in the m orn ­ing and then work with it in the afternoon. In the w inter m onths, when the tem pera­ture hovers around 40° to 45°F, an epoxied surface can rem ain slightly tacky even after 24 hours.

You m ust be pa tien t with epoxy when w orking in an u n h ea ted space. Space heaters are no t always the solution. I have used a kerosene space h ea ter to warm the shop and accelerate the ra te of cure, b u t found, to my dismay, that the incom plete com bustion o f the kerosene leaves a m inute residue in the air that can foul the m aterial surfaces, in te rfe rin g with the epoxy’s ability to bond. Both propane and natural gas space heaters have similar p rob­lems also, creating water as a byproduct of com bustion. If you are tem p ted to use space heaters, use electric quartz heaters. These infrared heaters do no t heat the air, ra the r they heat the surfaces of the objects the infrared waves encounter. You can find quartz space hea ters at m ost industrial equipm ent suppliers.

None o f the suppliers of boatbuilding epoxies actually m anufactures th e ir own

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D e v l i n ' s B o a t b i i l d i n

E p o x y S y s t e m s

raw resins and h ardeners . Each supp lier formulates its resins and hardeners by mix­ing base stock m aterial with various addi­tives th a t vary the epoxy’s p roperties and perform ance.

As a very rough ru le o f thum b, the g rea te r the p ro p o rtio n o f resin to h a rd ­ener, the h a rd e r the cu red epoxy will be. For exam ple, epoxies th a t use two parts resin to one p a rt h a rd e n e r are generally m ore flexible than those using five parts resin to one part hardener. If you are con­fused by suppliers’ claims as to the physical p roperties o f the ir systems, I recom m end you experim ent on your own. Try to settle on one system th a t will m ee t all your needs. Consider product availability. Select an epoxy m anufacturer who supplies ade­quate technical manuals; the m ore specific the m anual, the better. Some form ulators have gone to the additional step o f dem on­strating how to use the ir p roducts in spe­cific boatbuilding applications, and m ain­tain a staff o f experienced technicians for te lephone assistance. A h igh level o f ser­vice is a distinct advantage.

Since the epoxy is the m ost critical com ponen t, i t ’s im p o rtan t th a t you n o t allow cost to prevent you from buying the best available. Most o f the failures o f boat­building epoxies have been with cheap sys­tems. The better epoxy systems come from reputab le com panies that have th e ir own research staff constantly testing to ensure a high-quality product.

O nce you have chosen a suitable epoxy system, you must be able to measure the resin and hardener in the exact ratios. I p re fe r using g rad u a ted cups, b u t when you get into the five-to-one systems, the use o f cups can be complicated. Still, for shop purposes, I use g raduated cups fo r small batches, and if I want larger batches, I m ea­

sure with graduated cups into a bucket for mixing.

Some systems use p reca lib ra ted pum ps th a t m oun t on the resin and hard ­en e r cans. O n e p um p stroke from the resin can, and one from the h ardener can, delivers the p roper mixing ratio.

Mechanical gear pum ps are also avail­able for high-volume dispensing o f the cor­rec t ra tio o f resin to h ardener. T he p u r ­chase cost o f these pum ps m ight be considerable, bu t as with all tools, d o n ’t scrim p; the co rrec t pum p will speed the construction process, help minimize waste, and deliver m ore accurate resin-to-hard- en e r ratios.

All m easuring devices m ust be kep t clean to function properly. They will tend to gunk up, co llect dust, an d build up residue until they simply won’t serve their in ten d ed pu rpose accurately. D uring his annual visit to my shop, the local fire mar­shal always com m ents that these buildups on dispensers are a fire hazard , and no am ount o f arguing seems to dissuade him. From th a t p o in t o f view g rad u ated cups work best because they get throw n o u t when past their prime.

I rou tinely check the epoxy work o f the previous day when I open the shop in the m orning. If a surface seems too tacky o r no t properly cured, the culprit is almost always im proper mixing. A quick check o f the d ispensers o r the p lu n g e r open ings usually proves me right. C older shop tem­p era tu res will m ake th e epoxy m ore vis­cous, which can affect the accuracy o f the m ete rin g system. If the d ispenser is clogged, use chem ical-proof gloves with long, sleeve-covering gauntlets to clean all the parts with solvent. Before reassem ­bling, lubricate the m oving parts that won’t have physical contact with the epoxy.

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D e v l i n ’s B o a t b u i l d i n g

After the p lungers are fully re loaded with the liquid, use a m easuring cup or a weight scale to be sure that the correct am ount of resin o r h a rd e n e r is being dispensed. Sounds easy enough , bu t c lean ing these dispensers is messy work.

SAFETY

The most controversial aspect o f epoxy use is the m atter o f safety. Stitch-and-glue boat­bu ild ing relies on epoxy to ensu re the strength and integrity of the seams and to seal all plywood surfaces. Because epoxy plays such a key role, it’s im portant to have a clear u n d ers tan d in g o f this g roup o f chemicals. T here is no way around it: The improper use o f epoxy can be injurious and haz­ardous to your health. But I th ink that con­stan t vigilance and con tinuous care for safe and p roper use will minimize the haz­ard. B oatbuilders using norm al p recau ­tions and staying safety-minded at all times can use epoxy with the best o f results while fully protecting their health.

The strongest advice I can give you is to keep epoxy o ff your skin. P ro longed contact with the resin an d h a rd e n e r can cause an allergic reaction—sensitization— in some people . O nce sensitized, the slightest con tact with the resin and h ard ­ener, th e ir fum es, o r even sanding dust from epoxy th a t h asn ’t fully cu red can bring on a reaction.

Keep epoxy off your tools, and always w ear gloves that p ro tec t wrists as well as hands. I know o f th ree exam ples w here boatbu ilders threw cau tion to the wind and suffered the consequences. Two were first-time builders o f boats, but one was a professional who should have known bet­ter. The com m on denom inator was failure to use p roper gloves. T he professional was

a reckless fool in all aspects o f his life. He refused to use gloves and would plunge his hands into acetone at the end of each job to clean off half-cured resin While using u re th an e paints, he would refuse to wear even the simplest dust-filter mask, let alone an organic-vapor resp ira to r o r even a fresh-air system. Predictably, he experi­enced lung dam age from the u re th an e p a in t and spen t several days sp itting up b lood. In addition , the exposure to the epoxy caused a rash on both wrists and his

Figure 5-2. Using a glassing box to saturate sections o f interior glass taping laminates. Note the large paper tub, top, used to hold larger amounts of mixed epoxy. The worker is using a squeegee to help spread the resin into the glass cloth; gloves, a Tyvek suit, and a canister respirator complete the outfit.

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E p o x y S y s t e m s

forehead that resembled a reaction to poi­son oak. T he rash would d isappear after five o r six days if he stayed clear o f epoxy, bu t as soon as he walked back in to the shop, it reappeared. In the end, he had to give up boatbu ild ing with epoxy alto ­gether, and the last I heard o f him, he was at work in a can factory.

W hen I consulted with the two am ateur builders, we traced th e ir reactions to the cleanup process. M ost gloves available to boatbu ilders are adequate fo r epoxy b u t will never stand up to cleanup solvents such as acetone o r lacquer thinner. T he finger­tips are weak, and after norm al use, the sol­vents can easily leak through to the skin. In both cases, I found that uncured epoxy had repeatedly been allowed to stay in contact with the b u ild ers’ hands. Over tim e, they each experienced increased skin sensitiza­tion. W hen c leaning up, d iscard th e th in latex gloves you used for epoxying and don heavy, solvent-proof gloves.

And then th ere’s “Devlin’s Law,” a vari­an t o f M urphy’s Law. A fter a goodly am o u n t o f experience I have identified th ree natu ra l tem ptations th a t you will experience w hen you are w orking with epoxy. Once you have epoxy on your gloves, you WILL have an itch on your nose, your eyes WILL need to be nibbed, and you WILL begin to sweat and need to wipe your brow. I guarantee you’ll experience these urges, and just as surely, if you succumb to tem ptations, you will experience some nose o r eye sensitiza­tion due to epoxy exposure.

T here is simply no alternative to con ­stant vigilance: using safety gear, working as cleanly as possible, and no t getting epoxy on your skin. K eeping Devlin’s Law in m ind, one reason fo r w earing a can ister resp ira to r— ap art from the fum es and dust— is to keep yourself from scratching

your nose. After fifteen years o f using epox­ies alm ost daily, the only reaction I notice is a slight constriction of the th roat during extended use. But when I use a respirator, I never experience the th roat irritation.

O f th e two epoxy com ponen ts , the h a rd e n e r is the m ost toxic. Keep this in m ind, particularly when cleaning the hard ­ener side o f your epoxy dispenser. Extreme caution should also be used when sanding partially cured (green) epoxy surfaces, as may happen in the winter in an unheated shop. Always wear a respirator and protec­tive clothing, even if it’s only street clothes that are laundered daily and cover all parts o f the body likely to com e in contact with u n cu red epoxy. If you insist o n keeping your beard, a full-hood, powered-respirator fresh-air system may be th e only answer, since regular cartridge-type respirators will no t seal properly over a beard.

T he bottom line, my macho friends, is to respect these chemicals; just because the hazards are invisible does no t m ean they are absent. If you are apt to disregard such hazards, and won’t adopt a fervent attitude ab o u t safety, build your boat using trad i­tional m ethods and stay away from stitch- and-glue construction.

I have seen a coup le instances o f alm ost m agical acts o f reverse gravity in which epoxy or its resin and h a rd en e r com ponen ts splashed up in to a boat- b u ild er’s eyes. In each instance we had to rush the victim outside to a water hose for a lengthy flushing o f his eyes, th en rush him to the em ergency room w here the d o cto r rep ea ted the process— n o t som e­th ing anyone w ould do by choice. Wear eye p ro tec tio n a t all times. Safety glasses d o n ’t work well for me because I find them uncom fortab le . And if eyeglasses are uncom fortab le, at som e po in t you’ll find

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D e v l i n ’ s B o a t b u i l d i n g

yourself working without them —and that’s when accidents happen. Even if you d o n ’t wear eyeglasses for vision, get yourself fit­ted with a p ro p e r expensive set o f frames with clear lenses. Spend som e m oney on them so you w on’t treat them casually and wreck them . T h en wear them constantly in the shop so you get used to them.

A nd even the p ro tec tion can ’t be taken for granted. I ’ve also seen a worker develop nasty-looking, painful hands as a reaction to latex disposable gloves, which in his case was probably a reaction to the talcum powder in them. He was fine after he switched to non-talc gloves over soft lightweight cotton liner gloves.

M oderation is the best p ro tec tion . Always show er a fte r a work session; it will help keep your body clean an d healthy. Also d o n ’t forget to launder your clothing often. Wearing the epoxy-encrusted clothes day after dayjust continues to expose your­self to uncured resin o r hardener.

B A S IC E P O X Y T I P S

1 always try to use the h o ttest (fastest- curing) hardener, taking into account the w eather and tem p era tu re . Some epoxy systems now provide custom b lends fo r specific w eather conditions, b u t even on the hottest days of the year, I have found that sim ple trial-and-error experim en ta ­tion with a couple o f slower h ard en ers helps m e identify the ap p ro p ria te h a rd ­ener for that day. Keep records for future re feren ce o f which com binations work best u n d er specific w eather conditions in your area.

I t is also im p o rtan t to store the resin and hardener at a consistent tem perature, especially d uring the w inter m onths. The b e tte r you contro l the epoxy’s tem pera-

Figure 5-3. A used refrigerator is great for stor­ing of epoxy resin, hardener, graduated cups, stir sticks, chip brushes, and disposable gloves. For winter storage, a small 75- or 100-ruatt lightbulb will keep the con tents nice and warm for easier use.

tu re, th e su re r and m ore consistent the cure rates will be.

A way to keep the resin and hardener at a un ifo rm tem p era tu re is to store the dispensers in a heated box. In my shop we use old re frigerators with 100-watt light bulbs fo r heat. W ith the com pressor off and the light bu lb on, the sealed in terio r stays at abou t 80°F. T he freezer com part­m en t also makes a handy place to store gloves, stir sticks, mixing cups, fillet squee­gees and o th e r epoxying paraphernalia . O f course, make sure that the refrigerator

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E p o x y S y s t e m s

door is secure from inquisitive children.As m en tio n ed , mass also affects the

ra te a t which the epoxy kicks off. T he smaller, m ore confined , and narrow er- m outhed the mixing container, the ho tter the exothermic reaction and the faster the epoxy will go off. Consider transferring the epoxy in to a larger flat-bo ttom ed tub o r tray to slow down the exotherm ic reaction and extend your working time.

Thin coats o f epoxy app lied with a ro ller o r squeegee take m ore time to cure th an th icker applications such as a taped epoxy-and-fiberglass hull seam, because the h ea t dissipates easily from a th in coating. W hen clear-coating panels o f plywood with epoxy, you can apply an ex te rnal h ea t source such as a heat gun o r hea l lam p to warm the en tire coated surface. This will also help level the epoxy coating (helps to flow out) so that your surfaces are sm oother and require less labor to prepare for paints o r varnishes. Use caution, however, w hen applying heat to the first coat of epoxy on a dry wood surface. I t’s quite easy to lower the viscosity o f the epoxy sufficiently to drive a small am o u n t o f it in to the w ood grain . While this doesn’t compromise the sealing process, it may create finishing problem s, because the th in epoxy can displace air bubbles (out-gassing) from the wood grain, causing the epoxy to cure with a pocked surface and necessitating an o th e r sealing coat. You can avoid this with a slight and very even application of heat.

Epoxy also seems to magically appear on every tool, clam p, and boatbu ild ing device in the shop. Epoxy crud can rear its ugly head anywhere. Its appearance may n o t b o th e r you initially, b u t soon this residue will diminish the usefulness or pre­cision o f your tools. T h a t’s why it’s im por­tan t to clean u p afte r each jo b . Epoxy

rem overs are available from m ost m an u ­facturers, an d solvents such as acetone and lacquer th inner will work well, too, on partially cu red resin . Use long-sleeved, so lvent-proof gloves w hen w orking with these solvents, since any skin con tact will strip away your skin oils, which are your first line o f p ro tec tion . I f a tool d epends on lubrication, you will need to relubricate it a fte r each c lean ing with solvent. I have experim ented with a n u m b er o f d ifferent lubricants and have fo u n d that ligh t oils such as WD-40 work best on tools that might be fouled by epoxy. Do n o t use epoxy sol­vents on tools such as ham m ers: T he sol­vent m ight loosen the glues used to assem­ble the tool, an d you certainly d o n ’t want to see ham m er heads flying a ro u n d the shop. Wipe off what you can, bu t it is better to clean these tools by sanding or chiseling off the epoxy crud after it has cured.

A suitable natural cleaner for uncured epoxy resins is white vinegar. Soaking the fou led tool o r ob ject in the v inegar will cause the epoxy resin to tu rn milky white and thick and eventually roll off the tool. Rinse with clean water and dry. You could also use vinegar to clean hands o f uncured epoxy, b u t th en you sh o u ld n ’t be finding yourself in that position anyway.

T he fru stra tion o f keeping a clean shop is experienced by everyone who works with epoxy. O n a recen t trip, I had a chance to visit th e bo atb u ild in g shop of the G ougeon B rothers in Bay City, Michigan. From their excellent book, The Gougeon Brothers on Boat Construction, I gath­ered they had solved the problem s o f keep­ing a tidy shop, an d I w anted to see how they had done it. I found a well-organized shop an d a crew with excellent work habits; but, like me, they haven’t found a foolproof way to work with epoxy and keep

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D e v l i n ’ s B o a t b u i l d i n g

everything clean. If one works u n d e r the pressure o f deadlines, it will always be frus­trating to work cleanly with epoxy, but try!

F t L I i E R S

Fillers are used to modify epoxy for various applications, from fairing com pounds to structu ra l adhesives. Fillers are always ad d ed after th e p ro p e r re s in /h a rd e n e r m ix tu re has been thorough ly b lended . You’ll find a g reat variety o f epoxy fillers on the m arket, includ ing specialized for­m ulations fo r everything from high- strength hardw are bonding, to easy-sand­ing fillers. They are all quite expensive. I am o f th e o p in ion th a t a g reat variety is unnecessary. I have found that I need only three basic fillers: wood flour, Cabosil, and m icroballoons. T hese fillers adequately answer a variety o f b oatbu ild ing needs, and help to keep the overall material cost of the hull down. I m ight have ju s t a small am oun t o f high-density filler on han d for some hardware bonding purposes bu t the major players are wood flour, Cabosil, and microballoons.

Wood Flour

Wood flour fits the bill for stitch-and-glue boatbuilding because it is inexpensive and creates exceptionally strong jo in ts . It is both a bulking and thixotropic filler, which means it will make a thickened epoxy that tools easily in to jo in ts b u t also stays in place once you’ve finished the application. W ood flou r is little m ore th an th e finely g ro u n d sawdust com m only used in the baking industry as a cellulose filler for breads (fiber additive, if you m ust know) and in the manufacture of wood putties for hom e construc tion an d cabinetry. It is

finer than the sawdust m ade by your table saw or belt sander. H ere in the Northwest, w ood flou r is listed in the Yellow Pages, and I usually buy it in 50-pound bags. It is also available from most epoxy suppliers. If i t’s not, yell and they will soon develop a supply of it.

Wood flour mixes uniform ly with epoxy, making a thick paste. In my shop, we keep ad d in g un til th e shininess o f the epoxy has d isappeared an d th e m ixture looks like thick, creamy peanut butter. I use this paste to create the base for ou r stitch- and-glue com posite seam w herever ply­wood sheets m eet in the hull structure, and to cove (fillet) the jo in ts for all perm anent in te rio r structures. W henever I attach a cleat o r shelf, I use the paste on the facing surfaces to glue the com ponents in place.

By its nature, wood flour is the perfect p a r tn e r to jo in plywood panels and the wood com ponen ts o f the boat because it shares the same cellulose composition and provides a close color m atch. I find it dis­concerting to see a well-built boat wit h pur­ple m icroballoons o r white m icrospheres g laring o u t from every seam. If you p lan to finish your in terio r bright, wood flour is the only way to go.

You m ight ask, as many do, “Why use a filler a t all?” T he answer is sim ple. I t’s nearly im possible to cu t all com ponents fo r a p erfec t fit, an d th e re will be slight gaps betw een the surfaces being bonded together. Clear epoxy may run ou t o f the jo in ts o r fail to fill th e gaps and voids. Thickened epoxy will eliminate both prob­lems while creating a jo in t that is actually stronger th an the pieces being jo ined . If your jo in ery is perfec t th en by all m eans show it as such, bu t you can create a fine- looking boat with structura l fillets th a t’s probably stronger to boot.

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E p o x y S y s t e m s

Cabosil

Cabosil is a white pow der that is used pri­m arily as a th ixo trop ic additive. It helps prevent epoxy from sagging on vertical sur­faces, an d it can enable you to apply a thicker sealer coating o f epoxy in a single pass w here u n th ick en ed epoxy m ight requ ire several coats to achieve the same depth. I also mix Cabosil with wood flour to achieve a smooth, thick fillet on a verti­cal surface; it’s not colored enough to take away from w ood flo u r’s n a tu ra l color. Cabosil is a versatile filler that can be com­b ined with o th e r fillers to create custom blends tailored to a specific task.

M icroballoons

W hen filling low spots with a th ickened epoxy fa iring com pound in p rep ara tio n fo r the final pa in ting o f the boat, wood flour has a couple o f drawbacks. First, it d o esn ’t sand easily, an d its density is g rea ter th an necessary fo r a sim ple fill­in g / fairing operation. In such cases I p re­

fer an easier-to-sand com pound m ade with epoxy and m icroballoons. M icroballoons are lightw eight pheno lic spheres, light p u rp le in color, and w hen m ixed with epoxy, they make a dark purple filler that is easy to sand and sculpt. I th ink its color is unsightly and distracting in boat interiors unless the surface is painted, bu t I do like its ability to h o ld a fea th ered edge w hen sanded and to fill an unfa ir surface m ore rapidly than a wood flour mixture.

Finally, th ere is one add itional filler th a t can be a real time-saver. G ou g eo n ’s West System 410 M icrolight fa iring com ­p o u n d is 30% easier to sand th an m icro ­balloons, mixes in to the epoxy faster, and has a tan color similar to wood flour’s nat­ural color. Since it’s less dense an d easier to sand than microballoons, many builders do most o f their fairing with Microlight. It’s m ore expensive, b u t it sure saves sanding and fairing time. Just make sure after using M icrolight to reseal the surface with epoxy to help elim inate any difference in poros­ity (which would foul a paint jo b quickly).

F i b e r g l a s s Cl o t h a n d Ta p e

Fiberglass fabric is an im portant part of the stitch-and-glue construction m ethod. It is used to re in fo rce epoxied and filleted joints, sheathe exterior surfaces o f the boat, an d re in fo rce panels. F iberg lass/epoxy laminate helps exclude moisture and pro ­vides additional abrasion-resistance. It sig nificantly improves the final strength and appearance o f the stitch-and-glue boat, and without it, the integrity o f an epoxied boat would be greatly compromised.

Fiberglass comes in various forms for boatbuilding, including woven and knitted cloths, and a random-fiber m at that resem­bles a coarse felt. Two are used extensively for stitch-and-glue construction . T he woven cloth (and for o u r purposes in this book, any woven fiberglass fabric is a cloth) is particularly suited for use over composite joints (i.e., anyjo in t reinforced with resin, fabric, and a fillet material) in small boats. But w hen bu ild ing larger boats in which g rea ter stresses will com e to bear on the jo in ts , the kn itted biaxial fabrics are n e e d ed in tandem with the woven cloth to create strong, layered seams. In all stitch-and-glue boats the strong epoxy/fiberglass com posite jo in ts

replace the chine logs and frames o f a tra­ditional plywood boat.

To understand how fiberglass makes a b o a t’s jo in ts stronger, the bu ilder m ust understand how the fabric is constructed. Fiberglass is m ade from continuous fila­ments o f polyester glass, which are drawn or pulled from m olten glass through precise, m ultiholed bushings. These filaments are com bined into strands. D epending on the type of fiberglass, there may be from 51 to

Figure 6-1. Three types offiberglass cloth used in stitch-and-glue boatbuilding: 6-ounce cloth, upper left corner; biaxial cloth, upper right; and peel-ply, bottom, used to make smoother laminates and ease sanding.

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F i b e r g l a s s C l o t h a n d T a p e

Figure 6-2. Fiberglass cloth tape overlaps at the chine joint.

1,224 f ilaments per strand. T h inner strands are called threads, and thicker strands with m ore filaments are yams. Fiberglass is avail­able in a variety o f forms an d will be char­acterized by th e following properties: the num ber o f yams per inch in each direction, the w eight o f the fabric in ounces p er square yard, the thickness in thousandths of an inch (mils), yarn construction, weave style, and finish. Most fiberglass fabrics are coated with lubricants so that the filaments won’t fly away during the high-speed weav­ing process, an d to ensure a un iform appearance. After the weaving is done, the fabric is heat-cleaned to remove most o f the lubrican t. U nfortunately, the h ea t also greatly reduces the tensile s treng th o f the strands. All woven fiberglass products share this p roblem ; if the strands n eed to be woven, lubrican t is requ ired , b u t the hea t used to rem ove the lu b rican t dim inishes the fiber strength.

It was only a matter o f time (years actu­ally) until som eone asked, “Why weave it?” C onsequendy, the new developm ents in

fiberglass technology switched from woven to knitted fabrics, which for o u r purposes m ean biaxials an d triaxials. K nitting m achines easily han d le the glass yarns w ithout lubricants. T he g reatest boon to us, besides m aintaining the original tensile strength, is that knitted fabrics can orient the fibers at 45° if desired, ra ther than only 90° as with woven fabric. With this o rien ­tation, m ore o f the fabric crosses the jo in t, giving it immeasurably greater strength.

Knitted fabrics are rougher in texture th an woven fabrics; if used alone, they d o n ’t finish nearly as sm oothly as the woven cloth. T he usual solution in stitch- and-glue construc tion is to use a woven clo th as th e final surface layer over the knitted layers. For the in terio r seams o f a stitch-and-glue boat multiple layers o f knit­ted cloth covered with a layer o f fiberglass tape significantly speed up the glassing of the hull and bulkhead seams. But when it comes to fiberglassing the upper portions o f the boat— the m ore visible areas and places w here you m igh t w ant a m ore tran slu cen t o r b rig h t finish—biaxial o r kn itted fabrics are unsuitab le, an d the cloth tapes make for a m ore sightly joint.

S teer clear o f p rem ade woven fiber­glass tapes, because th e ir finish sizing reduces the wet-out capability o f the epoxy, an d the woven edges will ten d to cause puckers in the m iddle o f the tape. W hen applied over in terio r joints, these tapes do n o t flex o r conform as well to the different angles and shapes o f a boat. It is far m ore economical to cut your own widths o f fiber­glass tape from the standard 50-inch-wide, 6- o r 8-ounce cloth woven material used for ex te rio r shea th ing o f the hull. U nro ll a leng th o f th e woven fiberglass clo th on a table and use a s traigh tedge and a sharp knife— I like to use a single-sided razor

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D e v l i n ’ s B o a t b u i l d i n g

Figure 6 3. Cutting fiberglass cloth tapes from a roll of 6-ounce cloth with a safety razorblcule and a straightedge. A slightly diagonal cut to the weave eliminates some of the unraveling.

blade— to cut strips at an angle o f about 20 degrees to the weave. This helps keep the edges from unraveling d u rin g handling , and helps the tape conform to the joints.

W hen designing a stitch-and-glue boat, I exam ine each seam and jo in t for the level o f stress it will experience to d e te rm ine the n u m b er o f layers o f fiber­glass or the am oun t o f filleting that must be done. T he h ig h er the stress, the m ore layers o f fiberglass tape necessary for ade­quate strength. T he thickest seams will be in the in terior main hull joints, the m ajor bulkhead attachm ents, and the cabin and cockpit flats. These usually require two or three layers o f tape—each one wider than the one before so that each bonds in part directly to the wood, and the jo in t is

tapered. In boats larger than dinghies or skiffs I use layers o f biaxial fiberglass tape, along with a woven fiberglass finish layer to smooth the joint.

T he exterior fiberglass/epoxy sheath­ing serves two functions: It helps maintain a matrix o f epoxy sealing that would other­wise be h ard to regula te , and it adds con ­siderable abrasion resistance. Local areas prone to abrasion can be further reinforced with additional layers of fiberglass cloth. A good exam ple m igh t be an extra layer o f cloth on the foredeck w here the anchor m ight som eday be accidentally d ropped , or on the forefoot o f a flat-bottom ed dory that is likely to be beached frequently.

Some designers an d builders argue th a t shea th ing the ex te rio r o f the hull is

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F i b e r g l a s s C l o t h a n d T a p e

Figure 6-4B. Typical stitch-and-glue section.(Stephen L. Davis)

to extremes to ensure sm ooth and fair fin­ishes, b u t to my dismay, no m atte r how m uch care and effort we p u t into achieving a sm ooth finish, several weeks later, tell­tale weave patterns will appear. The darker the finish pain t, the m ore noticeable the pattern . T he epoxy com panies claim that dark p a in t absorbs an d creates too m uch heat and causes the epoxy to change shape slightly. T he pain t companies po in t at the epoxy as the culprit. A nd everybody sus­pects the fabric companies, who, o f course, deny any problems. Frankly, I have no t fig­u re d it out. T he m ost perp lex in g p a r t is th a t the prin t-th rough is occurring in the ligh t colors, too, w here there shou ld no t be any heat problem .

Selection o f one o f the h a rd e r epoxy form ulations seems to reduce prin t- th ro u g h , because the h ea t deform ation tem peratu re o f the h a rd e r epoxy is h igher th an th a t o f a m ore flexible system. Using

Figure 6-4A. A stitch-and-glue, bottom, versus a Conventional joint. (Stephen L. Davis)

unnecessary, b u t you shou ld resist every tem ptation to skip this step because doing so will significantly decrease the longevity o f your boat. I use 50-inch-wide fiberglass cloth, and at the stem, keel, and any jo in ts where this sheathing meets, I overlap the edges to gain additional strength . Always make sure at least two layers o f cloth rein ­force the exterior jo in t seams.

For exterior sheathing of the hull and some sections o f the decks, I like to use no heavier th an 6-ounce woven fiberglass cloth. W ith anyth ing heavier, the weave p a tte rn will p r in t th ro u g h the final pa in t finish. Print-through problem s seem to be on the increase lately. In o u r shop we go

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D e v l i n ’ s B o a t b u i l d i n g

Figure 6-5. Cloth sheathing overlaps on a hull, and their sequence of application.

Figure 6-6. Topsides telegraphing— the neme­sis o f a dark painted hidl. Is the dimpled pattern around the porthght a problem with the dark paint? Or is it a problem with the epoxy resin system? Probably it’s a combina­tion o f both factors, and may be related to microscopic air bubbles entrapped in the epoxy resin and glass laminate.

4-ounce fiberglass cloth for sheathing also helps, because the finer weave o f the fabric has less tendency to print-through. Finally, the longer the epoxy has cured before paint­ing, the less noticeable the print-through.

If you insist on a dark hull color, try a sim ple test. Prepare two identical, fiber­glass-sheathed panels m atching your hull surface; paint o n e with your dark paint, the other with white paint. Build the pan­els exactly as you will build your boat, using the identical procedure for preppirtg and painting the surfaces. Set these freshly painted test panels in the sun, and, using an ordinary meat thermometer, check the surface temperatures. O n a good hot day the dark surface may easily rise above 140°. T he light-colored panel on the other hand might be just 120CF. T he heat deformation temperature threshold (the point at which epoxy m olecules begin to migrate and shift in relationship to each other) o f m ost epoxies is ju st above that temperature. If your paint will heat the epoxy to this criti­cal point, you may well be risking not only

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F i b e r g l a s s C l o t h a n d T a p e

the fairness o f the finish surface but also the integrity o f the structure.

To alleviate print-through, use an epoxy system on the exterior sheath ing that has the h igh est possible h eat defor­m ation tem perature. (You m ight get this inform ation from the m anufacturer.) Further^consider m atching it with a light­weight woven fiberglass cloth (4-ounce) to m inim ize the texture, and use white or a lighter color o f paint to reduce the poten­tial surface tem perature o f the hu ll and other fin ished surfaces. W hile not a panacea, these precautions will help.

For exterior sheath ing you do have som e choices other than fiberglass cloth, with synthetic cloths such as Xynole, Dynel, and Kevlar. In my exp erien ce , D ynel is m uch harder to sm ooth out because it stretches easier, but it will give you a very ser­viceable hull sheathing. My main complaint is its lack o f availability. You can only buy it from one source that I know of—Defender Industries. X y n o le ’s availability is even m ore limited. Kevlar is expensive, but it’s a good choice where h igh im pact resistance is required— such as the bottom o f a h igh­speed boat used in shallow, rocky waters. My own shop skiff, a 16-foot garvey with a 40-horsepower outboard, has a Kevlar-

sheathed hull. If you ch o o se Kevlar for sheath ing, be ready for a real jo b — m uch m ore hassle than fiberglass cloth or Dynel or Xynole. Kevlar is difficult to wet out, and unlike fiberglass cloth , it d o e sn ’t go clear when it’s saturated; you can't cut it with nor­m al scissors or razor knives and you must add a layer o f fiberglass c loth before you can sand it. Vacuum bagging works well for Kevlar, but that introduces quite another set o f technologies and hassles.

Som e builders avoid a few o f the has­sles o f Kevlar sheath ing either by putting a layer betw een plies o f plywood cold m old ing (on a big boat) or by sheath ing the b oat’s interior. In each case it hardly seem s worth the effort to gain the impact resistance that Kevlar m ight add— and interior sheathing makes no sense to me.

I d o n ’t know o f a legitimate reason to use carbon-fiber cloth for sheathing. A ply­w ood structure such as a stitch-and-glue boat really doesn’t need carbon-fiber prop­erties to be strong and lightw eight. A nd carbon fiber is extremely expensive.

T he bottom lin e is it’s hard to find fault with good o ld readily available glass cloth for exterior sheathing. Be sure to buy on e o f the finishes that is epoxy-compati- ble. Your supplier will know which is best.

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S c a r f i n g

T he overall length o f the b o a t will d e te r ­m ine the leng th o f the plywood sheets you’ll need . S tandard m arine plywood sheets m easure 4 feet by 8 feet, and metric sheets (most im ported plywood) measure 4 feet 1%. inches by 8 feet 2%. inches. Thus, for boats longer than 7 feet 6 inches (account­ing fo r side cu rvatu re), plywood pieces m ust be scarfed to g e th er with tapered ,

glued joints into the lengths needed.T he scarf jo in ts between pieces need

a m in im um length-to-thickness ratio o f 8:1, and up to 12:1 is acceptable.

The longer the glue line o f the scarf, the stronger the resulting jo in t. A longer scarf also facilitates a m ore uniform bend in the scarfed section o f the panel, mak­ing fo r a sm oo ther hull curvature and

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1

S c a r f i n g

Figure 7-2. Several sheets o f plywood stairstepped prior to scarfing. I f the overlaps o f the panels are equal, the scarfing ratio will remain consistent when the stack is planed.

shape. It’s sometimes possible to purchase longer, pre-scarfed panels from specialty plywood suppliers. This is really no t as expensive an op tion as you m igh t think, because the freight costs will be the same w hether you o rder 4-foot by 8-foot pieces, o r longer, pre-scarfed panels. Plywood freight charges are determ ined by weight, no t by the size o f the bund le. T he down­side o f these panels is th a t the quality o f the scarfs may be questionable; the sup­p lier o ften pays little o r no a tten tio n to m atching grain and color to achieve uni­form panels, an d occasionally even the ir glue-ups are mediocre, bu t if you’re intim­idated by scarfing it’s a good alternative.

T here are basically five m ethods o f scarfing your own panels. The first option

is to buy a scarfing attachm ent that bolts to a circular saw. These attachm ents cut rea­sonably uniform bevels on the edges to be scarfed. T he G ougeon Brothers m arket a jig called the #875 Scarffer that does amaz­ingly well for its simplicity. I t’s easy to use, comes with a simple, descriptive m anual, and costs about $30. T he only drawback to the Scarffer is that when attached to a 7)4- inch c ircu lar saw, it w on’t cu t cleanly th rough m ore than /^-inch-thick plywood. You’ll have to hand-p lane to finish the scarf bevels on panels thicker than %-inch.

The second option works quite well if you have a less-than-extensive collection o f tools. Stack pieces o f plywood in a stair­case fashion, and with a router, h an d , o r power plane, knock off the “stair steps” of

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D e v l i n ’ s B o a t b u i l d i n g

the stack, creating sm ooth and consistent bevels. Place a p iece o f scrap u n d e r the stack o f pieces, so that it acts as the bottom stair step, cu tting your bevels th ro u g h to the scrap piece. I prefer this m ethod when scarfing odd-sized panels o r when I ’m sim­ply too lazy to set u p my large scarfing table. O nce m astered, this is also the best technique for scarfing dim ensional woods to be used in masts, booms, sheer clamps, and rubrails. I consider staircase scarfing a basic m ethod o f boatbuilding, and every boatbuilder should m aster this technique.

T he third option is to build a scarfing m achine. I w ouldn’t recom m end this for the am a teu r o r one-tim e builder, b u t if you’re bu ild ing a lo t o f boats it m ight be w orth th e expense. I had probably bu ilt ab o u t 100 boats with th e G ougeon B ro th ers’ Scarffer w hen I dec ided th a t I was b u rn in g u p too m any circu lar saw motors. So, necessity being the m o ther of invention, I built a scarfing table on which I could cut consistent bevels using a 6-inch- wide M akita #1805B h an d pow er p lan e r ru n n in g o n rails. I t is im p o rtan t to keep the knives on the power p laner as sharp as possible. W hen scarfing, I keep several reserve sets o f sharpened knives on han d so they can be changed quickly.

T he fo u rth alternative fo r c reating long panels, particularly w hen build ing a boat larger than 30 feet, is to buy your ply­w ood in th in sheets an d lam inate two or th ree layers to g e th er with staggered b u tt jo in ts . For instance, th ree lam inations o f J4-inch o r four lam inations o f 4m m would p roduce excellent p lanking stock for the hull o f a large boat. Vacuum bagging is the best way to assure even clam ping pressure while the epoxied layers cure. Lam inating panels works qu ite well, especially for creating long panels wider than 4 feet.

T he fifth m ethod is the brainchild of Jo h n Henry, who has invented a scarfing a ttach m en t that bolts o n to th e base o f a Makita han d power planer. A snap to use, the a ttachm ent can be adjusted to set the p laner’s knives at various angles.

W h e th er you lam inate o r scarf your panels, you will need a level work area with good ventilation. You can use a patio, shop floor, o r even a loft, b u t m ake the surface as absolutely level as possible. If you use sawhorses to support the pieces while scarf­ing, be sure to level them so that the scarf jo in ts a ren ’t twisted o r bent. Before gluing th e scarfs, cover your work surface with

Figure 7-3. Using a hand power plane to straighten o ff the stairsteps o f the plywood panels.

'I

S c a r f i n g

Figure 7-4. Final dressing with a belt sander or a grinder will fin ish o ff the scarf bevels. Note the consistent lines o f veneer layers in the plywood panels. When dressed these lines will be perfectly straight and even.

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D e v l i n ’ s B o a t b u i l d i n g

plastic to prevent excess epoxy from foul­ing it. Have your work area and materials fully p rep a red before you start, because once th e bevels are coated with epoxy, th e re is n o tim e to waste as you position and clam p the panels. I coat the beveled edges with unthickened epoxy a full 15 to 20 m inutes before assem bling th e scarf jo in ts . D oing so allows th e epoxy to soak into the end grain, avoiding the possibility o f a w eakened, epoxy-starved jo in t. Just before final assembly, I recoat the m ating edges with epoxy th ickened slightly with wood flour o r Cabosil.

T he simplest m ethod I have found for applying pressure while clamping and glu­

ing m ultip le pieces is to use weights o r props from an overhead beam. Any kind of weights will work. I have found th a t plac­ing the weights on stiff 2-inch x 6-inch or 2- inch x 8-inch boards spreads the pressure m ore uniformly on the stack o f panels.

I use light nails o r staples to pin the panels in position until clamp pressure can be applied . Be sure to place plastic between the panel layers if you are scarfing several panels a t a tim e to p revent excess epoxy from laminating them together. For good clam p pressure w hen you’re ju s t c lam ping a few pieces, use long drywall screws an d a drill m o to r to screw a stiff piece o f wood over the top o f the panels

Figure 7-5. Weights stacked on pinned and glued scarfs can provide enough pressure to ensure a good scarf lamination. I f you’re gluing the scarfs, be sure to put plastic between plywood layers so excess epoxy will not seep out and glue your panels together.

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S c a r f i n g

Figure 7-6. A nail or staple through a scarf prevents slippage caused by the downward pressure of clamps or weights.

into a wood base o r piece o f stock on the bottom o f the stack. Make certain the dry- wall screws reach all the way th rough the pile. I space the screws about 6 to 10 inches apart in staggered rows. They have to be withdraw n after the scarfs are g lued and cured, and an epoxy-and-wood-flour paste used to patch the holes.

Be sure that the m ating surfaces o f the scarf are flat and smooth by moving a small stick o f wood back an d fo rth across the glue line to check the s c a rfs a lignm ent. Allow a couple o f days fo r the epoxy to cure fully, then sand the excess glue from the scarf joints.

Figure 7-7. A 2-inch sheet metal screw can be used with wood blocks to clamp a joint.

For a stitch-and-glue boat, lofting simply m eans taking the designed pane l shapes and draw ing them , full-size, on sheets o f m arine plywood. As in trad itional boa t­bu ild ing , the lo fting process is the most im portant stage o f building. The final shape o f the boat is dictated by the panel shapes; at stake are a pleasing appearance , efficient hydrodynamics, and overall perform ance. Any unfairness in the u n d erw ater panels will quickly affect the coefficient o f drag and change the way the boat moves through the water. I f the lines o f the hull are in any way crooked, uneven, or unfair, the result will be ungainly appearance and a boat ou t o f pro ­po rtio n . W hile it w ould be possible fo r a designer to provide full-sized patterns for a stitch-and-glue boat, and save you a lofting step, p ap e r patterns are unstable, and the results could be inaccura te an d u n p re ­dictable. The lofting process requires such a sm all am o u n t o f tim e th a t little is to be gained from providing full-sized patterns.

T hink o f a stitch-and-glue boat as if it were a banana. If you were to peel a banana, eat the fruit, and then reassemble the peels, you would have a banana shape again. F u rth erm o re , if you traced the

shape o f each fla tten ed segm ent o f peel on to cardboard o r kraft paper, you could then cut o u t and assemble a paper m odel o f the banana. In essence th a t is exactly what a boat designer does with a stitch-and- glue design. He o r she imagines the boat’s shape as a collection o f large peels, o r com­p o n en t parts, with their edges lying on the sheer, chine and, keel lines o f the boat. In lofting the stitch-and-glue boat, all you are doing is taking the designer’s outlines for the peels (panels) and drawing them full- size on flat plywood sheets. If you choose to bu ild a boa t design th a t was n o t origi­nally draw n fo r stitch-and-glue construc­tion, it becomes a little m ore complicated. You’ll have to follow the process described in C hapter 9 to generate your own peels or panel dimensions.

Drawing the full-sized panels is a simple p ro ced u re . For th e sim plest shape, a V- bottom ed hull, there are only two side pan­els, two bottom panels, and a transom. With larger designs, the lofting requires drawing full-sized bulkheads and additional interior m em bers to s tren g th en the hu ll athwart- ships (side-to-side) and longitudinally (fore- and-aft) . Any one o f these m any panels o r

51

Figure 8-1. An exploded view of a stitch-and-ghie boat.

in terior parts can drastically affect the final symmetry and aesthetics o f the hull, so each panel o r p a r t m ust be lo fted an d p roofed as accurately as possible. We will go into proofing in Chapter 13.

W hen lofting, if the boats are small enough to m ake this practical, I p refer to lay the m arine plywood on sawhorses to avoid working on my knees. This m ight no t be practical with bigger boats; lay the ply­wood on some w ooden cleats on the floor and you can cut w ithout your saw blade hit­ting the floor. W hichever m ethod you pre­fer, the panels m ust be level and flat. If the floor is uneven, begin by laying o u t and leveling battens (sticks) every 12 to 18 inches. Accuracy in lofting depends p a r­

tially on how level the panels are while you m ark the station an d d im ension points. Usually, station marks are at 12-inch inter­vals a long the plyw ood’s long edges. It really makes no difference w hat intervals the designer has ind icated , however, as long as you are faithful when determ ining and setting the true dim ension marks.

W hen setting station m arks, I use a drywall T-square with a 50-inch leg to m ark the full width o f the panel; this speeds up the process. If you have only a carpen ter’s fram ing or L-square, simply extend one leg by a ttach ing a batten . Be sure to doub le ­check all station marks for accuracy.

O nce the station m arks are satisfac­tory, begin to project the dim ension marks

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D e v l i n ’ s B o a t b u i l d i n g

Figure 8-2. Mark o ff stations with a drywall square.

o n to the panels. T he rule to rem em ber is feet-inches-eighths— the universal three- numeral designation for boatbuilders locat­ing exact dim ension points by m easuring distances a long given station marks. H ence, 3 -4 -2 on a blueprint translates to 3 feet, 4 inches, 28 inches from the edge o f the plywood panel. T he third num eral is eighths, never fourths, or halves, or any­th ing else. T he only possib le variable m ight be a plus (+) or m inus ( - ) sign; if these shou ld appear, it translates to plus or m inus a sixteenth o f an inch. Thus, 2 -5 -5 + translates to 2 feet 5% inches. The

m ore you use these triple num erals, the more second nature it will becom e.

With all the dim ension points in place, the next step is to place a batten along the points to draw the curved lines (the edges o f our banana p ee ls). D o this by driving small nails on each side o f the batten along its length so that the batten aligns to all the dim en sion marks. Be sure to avoid the tem ptation o f nailing through the batten. N ot only would that ruin a perfectly good batten, but it imm ediately affects the true curvature o f the line by not allowing you to adjust for fairness along the length o f the

2 -5 -5 + = 2 feet—5 inches—Ye inch plus 'At inch 3—4—2 = 3 feet—4 inches—% inch (no sixteenths)

Figure 8-3. Station marks and lofting on plywood.

53

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54

9Mo d e l i n g

T h ough it may seem like a trivial pursuit at first, the m od elin g process is essential to consolidating ideas about form, symme­try, and the details o f the final design. It is helpful to make a m odel o f a design before building the boat, as the steps are similar. In m od elin g , the builder gains under­standing and confidence about the steps o f construction, ideas about the look and feel o f the boat, solid n o tion s about color schem es, and details for all m anner o f m odifications. T he m odeling process can also be used to establish a design’s hydro­statics and power requirem ents, thus giv­in g the designer or builder clues to the full-size w eight, center o f buoyancy, and likely speed o f the design.

A stitch-and-glue project is so radically different from almost any other boatbuild­ing m ethod that going through the steps on a m odel can open a builder’s eyes and help him or her visualize the full-scale project.

What if the boat you really want to build isn’t available through the usual design sources? Well, you can commission a custom design, o f course, but your bud­get may n ot perm it that. A less expensive alternative is to adapt on e o f the many

existing plywood-on-fram e designs for stitch-and-glue construction. Plywood-on- frame designs proliferated for decades g o in g back to World War II and earlier, and a rich stock o f them exists. Most can be adapted with som e tim e and effort to draw up the panel plans and make the structural conversions.

A few years ago I fou n d m yself in a te lep h o n e discussion with Jo h n Ratzen- berger. John, w ho starred as Cliff Claven on the television program Cheers, was interested in a new catboat. After several weeks, we settled on Ted Brewer’s 22-foot Cape Cod catboat. It was designed, how­ever, for traditional sheet-plyw ood con ­struction rather than stitch-and-glue con­struction. Given J o h n ’s lim ited schedule, shuttling betw een H ollyw ood and his hom e in the Northwest, I felt that a con­version o f the Cape Cod design from plywood-on-frame to stitch-and-glue con­struction w ould be appropriate. The stitch-and-glue boat could be built faster and easier, and from Joh n ’s point o f view, it would provide simpler maintenance and better service over the long run. But could it be done? A nd how m uch work w ould

1

M o d e l i n g

Figure 9-1. John Ratzenberger and his Ted Brewer—designed catboat modified for stitch-and-glue construction.

the stitch-and-glue conversion entail?At that tim e, in fou rteen years o f

designing and building boats, I had never built to another design er’s plan. It wasn’t that the option didn’t exist, but simply that I enjoy design in g a boat and then see ing the project through to launching. But this case was an exception. I wanted to build the catboat for John , and I liked the Brewer design, so why reinvent the wheel? After a p h on e call to Ted Brewer to get his thoughts on converting the design to stitch- and-glue construction , and after arriving at an agreed price for the boat with Mr. Ratzenberger, the project was a go.

T he original design called for com pli­cated, heavy framing that would have been extrem ely difficult to seal with epoxy. It

also required many m echanical fasteners that w ould have obstructed and jeop ar ­dized the protective epoxy coating. A com­plicated backbone or b u ild ing setup is required before the b oatbu ild ing cou ld com m ence, and finally, the many parts in the framing dem anded careful layout and lo fting to achieve a fair hull. T h e m ore parts there were, the greater the chances o f com prom ising a h u ll’s fairness and maintainability.

With the endorsem ent o f the designer, w ho was enthusiastic about having the plans revised to appeal to a w ider audi­ence, 1 set myself on the path o f converting the plywood-on-fram e design to a stitch- and-glue design.

Over the years, I have found that the

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D e v l i n ’ s B o a t b u i l d i n g

Figure 9-2. No boxy shapes: Czarinna’s fan ln il stern.

m ost difficult inform ation to obtain for a new or m odified design is the correct shape o f the hull panels. Precise design o f these panels is my greatest concern, since anv com prom ise there may distort the hull shape from its d esign ed specifications. Indeed, any flaws in the panel shapes can be magnified in the final hull shape.

In my own, still-evolving path o f designing, I have used four different meth­ods to generate the shapes and dimensions o f stitch-and-glue panels. T he only real limitation is the degree to which a sheet o f plywood can bend or conform to the shape required. I have always b een con cern ed about achieving a boat that will function well w hile presenting an aesthetically pleasing appearance. T he traditionalist in m e always wants to avoid the stereotypical

plywood box shape at all costs. Just because o n e uses plywood sheets to construct a boat does not mean that the results have to look flat and constrained.

INTUITIVE DESIGN

Early in my career I used an intuitive approach to finding the shapes o f panels. This m ethod depends heavily on previous exp erience with plywood shapes. I would begin by cutting out small-scale hull panels from thin sheets o f balsa, and in a few evenings, several hull shapes could be gen­erated by regulating the outline shapes o f the panels and the depths o f the dart cuts in the bottoms. This kind o f exercise went a long way toward acquainting m e with the m any potentia l com binations o f panel

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M o d e l i n g

shapes and their fo ld ed results, and the finite limits o f plywood bending. The prob­lem was that the shapes o f the panels were generated before the lines o f the fin ished hull. It was difficult to draw an accurate representation o f the m odel’s lines after it was assem bled, even though the panel shapes were accurate. D im ensions that should com e from the drawings had to be taken later from the full-sized boat, after cutting and fitting the hu ll’s many pieces. O nly after several boats were built to the sam e panel d im ensions w ould I arrive at reasonably accurate dimensions o f the fin­ished hull.

Nevertheless, through intuitive m odel­ing, I designed several boats up to 30 feet lon g which, even today, I find interesting and at times m ore com plex than many o f my later designs. This m eth od led m e to the 20-foot scow sloop Lichen a couple o f years ago. T he shape o f that design was u n conventional en o u g h to defy proper sketching, yet som ehow 1 knew the result I wanted. I started that project by cutting out shapes o f thin (J4i-inch) aircraft ply­wood, and quickly came up with the hull I was looking to build.

W hat I had b een unable to sketch I was able to model. I like to think that how you get there is never as im portant as the final expression. Maybe it was a classic right brain—left brain dilemma.

CARVED HALF-MODE1/S

T he second way to get the panel shapes o f a stitch-and-glue design is to carve a chined, solid half-model to small scale (%" or 1" = 1'), then cover the m odel with trac­ing paper and trace the h u ll’s panel out­lines on the paper. W hen these tracings are laid out flat and the outlines faired

with a drafting batten, you get reasonably accurate and acceptable small-scale panel shapes.

U sing solid half-m odels always appealed to my sense o f tradition; it is, after all, close to the tried, true, and tradi­tional approach to design. But what com es first, the m odel or the hull lines drawings? Realistically, the answer is a com plicated com bination o f both, and the end result is usually a m anifestation o f som e vague vision o f what looks m ost pleasing to the designer. I always began by sketching a set o f prelim inary lines in an attem pt to define the rough edges or parameters o f the design. W hen satisfied with those lines, I moved to the workbench and carved the half-model. (The negative side o f the half- m odel approach is the difficulty o f accu­rately representing all the parts o f the full- sized boat.)

In m ost cases, while m aking the half­m od el I w ould revise the initial shape o f the hull to improve its appearance. T hen I would go back to the drawing board and redraw the lines o f the boat to match the half-model. T he danger is that every step from the drawing board to the half-model and back again com p ou n d s the chances for error. T he resulting design was som e­times so far afield from its original intent that I ab andoned (or shou ld have aban­doned) the whole project. But the biggest drawback is the time invested in drawing, m odeling, and redrawing, which tended to sap my inspiration level for the boat.

I n eed ed a quicker and m ore open- en d ed m eth od o f design ing, with less chance for error. A nd in the case o f the Cape Cod catboat conversion project for John , I n eed ed to stay true to the origi­nal Brewer-designed lines. From past exp erience with the half-m odel m ethod,

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I knew its accuracy would be questionable and that any changes w ould be tanta­m ou n t to prod u cin g a new er version o f the design. I was determ ined not to walk that path, both in respect for Ted Brewer’s original lines and because if 1 had wanted to do a full custom design badly enough, I w ould have p rop osed that right from the start.

COMPUTER-ASSISTED

DESIGN (CAD) SYSTEMS

T h e third m eth od for generating panel dim ensions is with com puter-assisted design, or CAD. To my eye, CAD lines on a screen can ’t com pare with a tactile, three-d im ensional half-hull m odel. T he com puter software presently available may be state o f the art, but it leaves a lot to be desired in the accuracy o f the information it generates and its ease o f use. When gen­erating the panel inform ation (plate pro­jection s, in software language), the com ­puter takes a com plicated m athem atical look at the hull with a specific series o f cal­culations. But the math base may n ot like som e part o f the boat’s form — a problem I’ve en co u n tered in two d ifferent CAD program s in the past few years. T he Czarinna series and the Oysta 42 have rounded fantail sterns, and the CAD pro­grams could n ot project the sterns prop­erly. T he only way to get around the math­ematical limitations o f the software was to break the boats in to bow and stern seg­ments, then splice them together with the computer. T he splice had to be extremely accurate and there was alm ost no way to fair betw een the two halves. T he effort involved m uch trial and error, and m ade for som e frustrating moments.

Further, m ost o f the com puter pro­

grams will make the lines conform to d evelop ed conical surfaces, w hile not te lling the designer how— or w here— to alter the original design’s lines. This auto­m atic process creates a problem if one wants to learn intuitively about hull shapes. Every set o f computer-generated hull pan­els I have built from has presented som e small, but irritating, error that required correction and com pensation . A nd with­out a fair bit o f experience under my belt I m ight n o t have spotted the error, and ended up with a real disaster.

O f course, I’m referring to the low- cost CAD packages, not the six- and seven- figure ship-design software programs. Most boatbuilders do n o t have ready access to the necessary hardware and software; even the simplest comprehensive CAD software costs well into five figures. O ne alternative is to locate a designer who regularly uses CAD and subcontract the panel conver­sion work. In fact, I decided to do just that, and through Ted Brewer’s lead, I found Jack B eaton from Coast Yacht D esign in Vancouver, British Columbia, who gener­ated all the panel inform ation for us. But as it turned out, I cou ld n o t obtain Beaton’s computer-generated information fast en ou gh to m eet Joh n Ratzenberger’s contracted construction schedule. Pressed by a tight timetable, I put on my thinking cap and cam e up with a fourth method.

PANELED HALF-MODELS

W hat I cam e up with I call the p an eled half-model, and it’s the simplest, quickest, and m ost accurate m eth od I’ve used. It produces a three-dim ensional m odel that can be quickly understood by som eon e without special skills. The builder can take the lines o ff any ex isting ch in ed design,

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M o d e l i n g

an d by build ing a p an e led half-m odel transla te the design in to stitch-and-glue panel shapes. If needed, the m irror image can be constructed so that scale model test­ing can be done for flotational character­istics such as loading, d isplacem ent, and appearance.

My approach was to reduce the boat to th e fewest, sim plest lines necessary to describe it. T h en I translate those lines in to th e fewest n u m b er o f parts th a t will comprise its three-dimensional shape. The side view, o r profile, o f a sim ple V-bot- tom ed boat w ould show th e sh ee r o f the boat as line #1, th e ch ine as line #2, the fairbody line as line #3, and the transom either as line #4 or the continuation o f the o ther lines, in the case o f a fantail stern or a double-ender. Rem em ber that the fewer the lines used to represent the design, the greater the potential accuracy.

T he profile o f the boat contains only half the inform ation necessary for an accu­ra te scale m odel, though. T he o th e r half is p rovided by th e half-breadth , o r top, view, which is the view a sea gull enjoys just before h e fertilizes your deck. This view gives the deck outline and the width o f the transom a t the sheer; the ch ine outline; and the half-beams from the fore-and-aft centerline to the sheer o r chine at an infi­nite n u m b er o f stations o r points. N ote also the perpend icu lar line from the out­side co rn er o f the transom and ch ine to the centerline.

To bu ild an accurate p lan k ed ha lf m odel, fou r shapes are required : (1) the long itud ina l profile o f th e b o a t w ithout any keel or appendages, showing the chine position; (2) the ou tline o f the half-deck (sheer plane) viewed from the top; (3) the ou tline o f th e half-chine p lane viewed from the top; an d (4) th e shape o f the

Figure 9-3. The simple lines o f a V-bottomed boat in profile and half-breadth views.

transom. Think o f these four basic shapes as th e skeleton over which th e skin is drawn. If your design is m ultichined, you will need the extra chine planes and their positions m arked on the profile.

Using an enlarg ing photocopier, you can enlarge the plans to the desired half­m odel scale, b u t be aware th a t p h o to ­co p ie r en larg ing is never perfectly accu­rate. W hether you are using lines taken off a boat o r the actual blueprints o f a design, if you want extremely accurate lines, go to

Figure 9-4. The four basic shapes o f a boat.

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a p rin ter and have a cam era enlargem ent made. O r you can take the table o f offsets and loft a scaled view of the boat yourself to the larger scale.

I recom m end working to the largest scale practical, and one that can be conve­niently read with an arch itect’s scale rule. At least, try to en d up with a m odel between 20 and 30 inches long. The scale you use may range from % inch to 3 inches to the foot. T he larger the m odel the potentially m ore accurate your half-model and your panel projections will be.

I prefer to use %-inch plywood for the m odel’s profile and %-inch plywood (door- skins) for the sheer and chine lifts. You can also use dimensional solid wood planed to the Vi- o r %-inch thicknesses. T he easiest way to transfer the lines o f the boat to your m odeling stock is using a pounce wheel (toothed wheel) or pinpricks through the paper onto the stock so that you won’t ruin

the original drawings. If you use pinpricks, fair the lines betw een the marks with a small batten. If you prefer, you can use car­bon p ap e r to transfer the drawing on to tracing paper. T hen glue the tracing paper to the stock directly and cut out the parts.

Unless the boat has a perfectly flat sheer o r chine (parallel to the waterline in profile ), the top view o f the boat p lan is n o t showing you the actual, u n b en t o r exp an d ed shape o f the sheer and chine planes. For an accurate half model, you’ll need to do a simple conversion drawing to ob tain the true shape. S tarting with the sheer, bend a light batten along the sheer- line on the profile from the side view. Assuming you began with the plans for a plywood-on-frame boat, the chances are good that the original drawing will include some station lines, so make a small m ark on the ba tten w here each o f the station marks intersects the sheer. If your plan

Figure 9-5. The catboat’s profile is shown on the plywood that will be used for making the model.

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M o d e l i n g

Figure 9-6. Spring a batten to the curve o f the sheer in profile, and mark its intersections with the stations.

does not show station marks, you will need to choose and place your own stations for reference. T he station m arks n eed to be shown on both the profile and the top view o f the design, aligning accurately between the two views. I use a m inim um of ten sta­tions on the two views to give an accurate reading of offsets.

O nce the b en t batten is m arked at each station on the profile drawing, inc lud ing the bow an d stern ends, unspring the batten and lay it ou t on the stock to be cut fo r the sheer lift. Using one straight side o f the stock for the centerline, lay the straightened batten along this edge.

(I f you run the grain o f the 'A-inch plywood perpendicular to the centerline, the plywood will bend to the sheer rocker with greater ease and

accuracy.) M ark each o f th e station m ark intersections along the previously bent bat­ten, as well as the intersections of the stem and transom points, then draw a line per­p en d icu la r to the cen terline on each of these marks. Now you can go back to the original drawing to pick off the next pieces o f needed information.

On the top-view plan, using a pa ir o f dividers o r a p ap e r tick-strip, m easure the half beams o f each station from the center- line to the sheerline. (If your design has a table o f offsets, use this in fo rm ation for half-breadths.) Transfer this information to the stock fo r the sheer lift a t each station, th en co n n ec t those half-beam m arks on the station lines with a flexible ba tten to draw the new outline o f the u n b en t deck

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Figure 9-7. The plywood panel that will become the sheer lift is shown sprung into place over the drawing.

Figure 9-8. Note how the projected spadngs cha?ige when the plywood is straightened.

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M o d e l i n g

Figure 9-9. The sheer lift, the chine lift, profile, skeleton o f the ha lf model.

lift. Unless the boat has a straight sheer par­allel to the waterline, the true, stretched- out sheer lift will be slightly longer than the top view indicated in the design. Repeat this process for the chine lift.

O n ce the sheer and ch in e lifts are drawn, the sheer lift can be overlapped on top o f the profile cutout and the thickness o f the lift cut away from the top o f the pro­file. T he chine lift will n eed the thickness o f the profile cu tout d ed u cted from its width so that it will reflect the true designed half-beam.

I have found that a p an eled half­m odel is best built from hull d im ensions m easured to the inside o f the planking, since the full-sized stitch-and-glue shell is thin en ou gh that the hydrodynamics will

and transom will form the

n ot change significantly. If, however, you make a half-model o f an older design not conceived for stitch-and-glue construction, check w hether the designer in tended for the lines to be on the inside or outside o f the planking. By building to the inside o f the hull design, your interior framework and lifts do not n eed to have the thickness o f the hull p lating subtracted from the edges o f the hull lifts, w hich w ould be arduous to do accurately.

U se a cyanoacrylate (CA) g lue for bonding the parts o f the half-model. Most hobby shops carry cyanoacrylates, an advanced cousin o f the instant glues found in your local hardware and drug stores. 1 like a brand called Zap-a-Gap, which works well with wood and the exacting fits neces-

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D e v l i n ’ s B o a t b u i l d i n g

sary for the half-model. I also use an accel­e ra to r with the Zap-a-Gap, called Zip Kicker. Used in com bination, these p rod ­ucts will set up instantly, helping to assure perfect alignment. If you tend to work on the sloppy side, purchase Z-7 D ebonder to help unglue mistakes. I read recently that accelerators for the cyanoacrylates may be damaging to the ozone layer, so a perfectly good option is to use baking soda. It is noi as fast an accelerator as Zip Ricker, bu t it is k inder to the Earth. I apply glue to the parts to be b o n d ed then sprinkle a p inch o f soda o n to the wet glue. A few seconds later the bond is set.

A nother helpfu l tool for fitting and beveling parts is a simple rasp m ade up of a %-inch x 1-inch x 6-inch block o f wood wrapped in a piece of 80-grit sandpaper.

O nce you have cut ou t all the parts for the profile, deck lift, ch ine lift, and tran ­som, and you have m arked the position of the ch ine line on the profile, you can begin the assembly of the half-model. I use tabs of glue about 14 inch apart to glue the lifts to the profile. Apply three o r four tabs, add the accelerator, and allow it to set up before m oving to the next section. Use reinforced filament strapping (packaging)

y*

Figure 9-11. A wood block wrapped with sandpaper makes a simple rasp for beveling the lifts.

tape to help hold the panels together while gluing. W hen you glue the chine lift to the profile, be sure to place the lift ju s t above the line that defines the chine position.

As you place the two lifts on the pro ­file, they must be exactly perpendicular to the profile. Plywood tends to bend well on only one axis, so the lifts will ho ld their true position b e tte r if the g ra in in the ch ine an d sh ee r lifts is p e rp en d icu la r to the profile. (If your design has a s trong sheer, you should consider using Italian pop lar plywood— or b en d er bo ard —as it will b en d truer to the sheer.) T he profile m ust be perfectly flat— it’s usually easiest to attach it to a thick, flat p la ten (slab o f scrap wood) with a dab or two o f glue. The centerline o f the two lifts musl contact the profile at all points. If you have persistent problem s hold ing the lifts perpend icu lar while gluing, cut o u t small, 90-degree squares from the door skin and glue them

Figure 9-10. Deduct the thickness of the sheer lift and profile to compensate for the thickness of the stock.

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in place to m ain ta in the p erp en d icu la r positions of the lifts.

T he next step is to attach the transom to the profile and the ch ine lift. A fter the parts are g lued together, you are ready to glue the skin over the half-model to achieve the b o a t’s fin ished shape. You’ll n eed to bevel the keel, stem, and deck edges of the profile and the sh ee r lift to accurately attach the hull skin to the half-model later, p roperly com pensa ting for the p lanking angle. Run the san d p ap er back an d forth on the edges. Complete the beveling o f the keel and stern first, and panel th e half- m o d e l’s bo ttom before going on to bevel the deck edge o f the sheer lift.

I like to use m o d e le r’s ^a-inch, three- ply birch aircraft plywood for planking the half-model, because this type o f plywood bends exactly in the scale m odel as the full- sized plywood does in the full-sized boat. An alternative is the J4-inch Formica-type lam inate used by cabinetm akers in the European-style cabinets so popular in con­tem porary house construction. This lami­nate is ha lf the thickness o f the standard Xh-i rich countertop grades, and it’s readily available, economical, and best o f all, pre-

Figure 9-12. Beveling is essential before attach­ing the hull skin.

co lo red—which m eans you can avoid pain ting your half-m odel later. I t cuts cleanly and precisely with good quality scis­sors, and glues well.

To panel the bottom, cut the plywood o r lam inate som ewhat larger th an the panel needed, and put a few drops o f glue on the forw ardm ost section o f bo th the profile and the chine lift. Glue from bow to stern, holding the panel in position with package strapping tape while the glue sets. With the bottom panel glued in place and trim m ed to shape with a single-edge razor b lade o r an X-Acto knife, you can now bevel the sheer lift. Again, work with the sandpaper rasp until the edge o f the lift is properly beveled to receive the side panel. Use the rasp with the san d p ap er only on the upper portion of the block where it will contact ju s t the sheer lift. In that fashion, you will bevel the sheer lift and n o t affect the bottom paneling or chine lift.

You can now cut out a side panel and glue it onto the lifts, working from bow to stern. O nce the glue has set, do the final trimming o f the edges of the panels on the hull.

If you in tend to attach the cabin struc­tures to the hull, this is the time to panel those parts. T he layout o f all cabin struc­tures is m uch easier if they are included in the profile o f the half-model at the begin­ning. Attaching separate pieces is m ore dif­ficult if each alignm ent has to be done sep­arately.

The easiest way to finish the m odel is to prim e the en tire boat with a sandable prim er, available a t the hardw are store. Put two coats o f p rim er on your m odel, then sand using 80-grit sandpaper for the rough spots an d 150-grit for the rest o f the hull after the first application. W hen the second coat o f p rim er has dried , fill

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Figure 9-13. The completed hull model gives three-dimensional life to the two-dimensional drawings.

any rem aining bad spots and use 220-grit sandpaper to sand the en tire hull smooth and fair.

For the finish coat, use a fast-drying spray enamel. The results are very smooth, and you’ll save tim e w hen applying th in m ultip le coats, w ith 15 to 20 m inutes between coats.

Take g reat care in m asking the o th er structures before you paint. Accent colors can be used for the deck anti cabin areas. And, w hen the pa in ting is done, you can use autom otive p in strip ing to show the w aterline, th e deck rails, and window edges. A contrasting color below the boot stripe will realistically accent the model. If i t ’s d o n e carefully, a p lanked half-m odel can becom e a real mantelpiece.

T R A N S F E R R I N G P A N E L I N F O R M A T I O N

W hen th e half-m odel is bu ilt accurately, an d the hull is fair an d true w ithout any twist o r irregularity, you can ex tract the true expanded shapes o f the hull panels. I have found that Mylar, a plastic drafting film available from office supply stores, is the easiest m aterial to use for picking off the panel projections. Mylar is translucent, and if you use a couple o f drops o f cyano­acrylate glue to lightly tack it in place on the m odel, you can trace extrem ely accurate ou tlines o f the panel shapes, th en easily rem ove it. Tracing p ap e r will work, b u t you can ’t glue it to the m odel without its tearing when removed.

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Make a series o f small pencil dots along the panel edges, taking care while marking the chine and sheer panels that the Mylar does not pucker or fold anywhere. It must be flat against each surface with full contact for the entire length o f the panel. This also will be the final check on w hether the design can be fully d evelop ed from ply­w ood, because Mylar, like plywood, only bends well in on e dimension.

After rem oving the Mylar from the half-model and fairing the panel lines with a flexible batten through the pencil dots, you are ready to do the conversions for the full-scale panels. M easure the lofting points on 12-inch scaled stations (e.g ., if your m od el is scaled 1 in ch to the foot, take m easurem ents o ff the Mylar at sta­tions 1 inch apart). U se the “feet-inches- e igh th s” d im ensional indications. After you’ve transferred the panel shapes, the only decision left is what scantlings— thick­ness o f plywood and other structures— to use in the full-scale boat (see Chapter 10).

BUILDING A I'UIili

FLOTATION MODEL

If you plan to tank-test your m odel, use the %" = V scale. At this scale, the m odel’s tow­ing speed will be exactly 25 percent o f the full-size boat’s potential speed. W hen I tow a test m odel, I weight the m odel down to the designed waterline. Pulling it beh ind a skiff at, say, 4 m ph, I use a video camera to record the m o d e l’s response, thereby approxim ating the d es ig n ’s full-size per­form ance at 16 m ph. Later, w atching the video and freezing frames, I can ana­lyze the bow wave and the wake action; som etim es even the effectiveness o f the spray rail or trim tabs can be noted. (See W eston Farm er’s From M y O ld B o a t Shop,

International M arine, 1979, Chapters 12 and 13. This book is out o f print but avail­able from libraries.)

In the M-inch-scale m odel, the weight o f the m odel is related to the full-size boat by the cube o f the linear ratio. Use a vegetable or meat scale to w eigh the m od el. If the linear scale ratio is 16:1, a 1-pound m od el’s weight can be projected to 4,096 pounds for the full-size boat. For ballast weight, a cop p er p en n y in %-inch scale translates to a roughly full-size weight o f 25 pounds. It can be great fun to check out the weights o f engines, fuel tanks, and everything else that m ight affect the cen ­ters o f balance and gravity in the boat.

Building a flotation m odel is most eas­ily done by following the half-model build­ing procedure and simply gluing lifts and planking up both sides o f the b oat’s pro­file. If you’ve already procured your panel- shape inform ation from a half-m odel or you’ve purchased a design made for stitch- and-glue construction, you can build your flotation m odel in scale as you would a full- scale version— simply cutting out the pan­els o f the boat and using nylon-filam ent packing tape (available from any drug or postal store) instead o f wires to stitch the boat. 5 M inute epoxy or CA glue can be used in lieu o f epoxy and glass joints as in the full-sized boat.

Loft and cut out the bottom panels as ou tlin ed in Chapter 8 and lay on e atop the o ther in a mirror im age. Fasten the panels a lon g the keel lin e with 1 ̂ -inch- long strips o f strapping tape, then spread them out to form the bottom shape. If you have trouble h o ld in g the panels apart, cut a small stick to use as a bottom spreader. Tape the side panels to the bot­tom panels, and place small scrapwood sticks as sheer spreaders to spread the top

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o f the m odel open. Assuming you have a stitch-and-glue design, you can go further with your scale boatbuilding and build the whole structure com plete with bulkheads and all. Glue together the keel lines and ch ine lines with 5 M inute epoxy or CA glue, and then cut out and install the bulkheads. Assemble the rest o f the boat by cutting each co m p o n en t until it fits properly, gluing it only w hen you’re sure it is properly shaped and positioned . Wherever you find a need for adjustment, make these changes in co lored ink on your blueprints; these notations may becom e very important information later. This is probably the greatest benefit o f the w hole m o d elin g exercise— it gives you a scale glimpse into the building process.

O nce you have the primary structure fitted and g lu ed into place, turn to the keel, stem , and deck structures. Literally every part o f the actual boat should go on the scale m odel to generate the most pos­sible inform ation from visualization and tow testing. There is an obvious limit to the detailing, but the true m odeling enthusiast will want to work in every last detail possi­ble, including testing out paint colors and schemes.

After painting, or at least sealing, the finished m odel is ready for tow testing. Or, you may simply want to place it on your man­telp iece or keep it near your workbench. [ have many times found a m odel helpful in keep in g m e inspired and m otivated while working on the full-sized version.

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Because it’s capable o f building boats from small dinghies up to 80-footers, the stitch- and-glue m edium obviously has a large am o u n t o f versatility. A stitch-and-glue boat larger th an a dinghy o r skiff will be subject to considerably m ore stress than the sm aller boat, and it will n eed add i­tional structure to de together the strong exterior shell o f the vessel and help keep it rigid.

Two basic types o f structure help with these loads: stringers and bulkheads.

Stringers are longitudinal beams, usu­ally lam inated in place, runn ing from bow to stern in as u n in te rru p te d a m an n e r as possible. Gunwales in small boats and sh ee r clamps in large boats fall in to the stringer category. S tringers usually are m ade from dim ensional stock, though th e re are exceptions w here parts, o r indeed the en tire stringer, m ight be lami­na ted from plywood. My S u rf Scoter, a raised-deck design, has so m uch shape in a po rtio n o f its sh ee r clam p th a t it p re ­cludes using dim ensional stock. I t would simply be too weak. Laminating it from sev­eral layers o f plywood cut to shape, though, is strong and works well.

Figure 10-1. Sawn-to-shape plywood sheer clamp lamination in the cockpit o f the 22-foot Surf Scoter. Note the notch cutout in the bulk­head to let in the sheer clamp. The lower inter­mediate sheer clamp has already been laminat­ed into place, and due to its straighter run, doesn’t need to be sawn to shape.

D e v l i n ’ s B o a t b u i l d i n g

Stringers are always g lu ed in place, then reinforced with mechanical fasteners. In m any instances I’ve used stringers to land o ther structures, which effectively helps spread loads.

Bulkheads, the other basic structure in a stitch-and-glue boat, are cut from large m arine plywood sheets and are set either athwartships, longitudinally, or flat. Think o f the stitch-and-glue boat as an old-fash­ion ed eg g crate, with an outside box, and partitions erected at 90-degree angles to each other to hold the eggs and prevent the crate from being crushed. T he stitch-and- glue boat works in m uch the same manner, distributing stress and loads through a grid- work o f bulkheads while protecting cargo and occupants in the various com part­m ents. Stresses m ust be distributed throughout the structure so no single area carries a disproportionate strain.

Bulkheads provide a defin ition o f space as well as support. A galley compart­m ent, for exam ple, can be created using structural bulkheads. It makes sense to use

the bulkhead system to create n eed ed space and increase the h u ll’s overall strength. By b on d in g each p iece o f ply-

Figure 10-3. Tim structural stringers luith attaching parts.

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Figure 10-4. The 29-foot Means o f Grace design showing a perspective of the bulkheads and fram ing structure o f a large stitch-and-glue boat.

wood and every stick o f dimensional wood with epoxy and fiberglass com posite joints, every com ponent becom es structural.

Bulkheads can double as berth faces, berth flats, cabin soles, cockpit soles, cabin sides, decks, cabintops, galley faces, galley flats, head bulkheads, engine beds, anchor locker bulkheads, and more.

As for the thicknesses o f these bulk­heads, when I first began building boats, I used fir plywood in the hulls. But not b ein g fon d o f fir’s appearance, I always painted it. I wanted the option o f varnish­in g som e interior parts, so I began using %-inch mahogany plywood simply because the local supply was good. W hen my source disappeared, however, I tried %-inch

mahogany bulkheads and was surprised to find such a significant im provem ent in rigidity. D uring the bu ild ing o f the boat, the %-inch bulkheads were comparatively hard to keep straight and square. T he %-

inch plywood was far m ore rigid and fit true— and its additional weight was m ore than com pensated by its stiffness and ease o f use.

Certainly, if I were constructing a m ultihull or racing m on oh u ll, overall w eight w ould be a concern . If k eep in g w eight to a m in im um is im portant, you m ight use bulkheads m ade from o n e o f the balsa-foam-, or honeycom b-core mate­rials. T hese are considerably lighter than solid plywood, but they cost m uch m ore

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per panel. For norm al cruising and inter- mediate-performance designs, 1 use %-inch marine plywood for all major athwartships and longitud inal bulkheads and for any flat surface that can be ju m p ed or walked on or subjected to severe strain. For a com­ponent well supported by a primary fram­ing structure, I use 14-inch plywood.

W hen se lectin g stitch-and-glue skin thickness, always think stiffer, sturdier, and stronger, and consider the service duty o f the boat. For instance, in my Surf Scoter design, the displacem ent scantlings would indicate a skin o f 12mm, or lA inch. But the majority o f the Surf Scoters will be either dry-sailed from a trailer or will live on a

trailer w hile wintering. That extra strain has to be figured into the b oat’s service duty. As a consequence, I selected %-inch thickness for the Surf Scoter’s hull, but with an extra layer o f X-inch plywood cold- m olded to the bottom for a total thickness o f % inch.

Bulkhead placem ent is important, too. Keep the m axim um unreinforced area o f skin betw een bulkheads, stringers, and other primary structures to no m ore than 12 square feet.

In my designs, I use several types o f rigid-clamp support systems at the sheer. T h e sheer clam p provides a strong, stiff, and fair curve up at the edge o f the hull. In

Disftfocement W eight in Pounds

Figure 10-5. Plywood skin thickness varies according to displacement.

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Figure 10-6. External, right, and internal sheer clamp arrangements. The internal sheer clamp arrangement is often used for larger boats.

the initial building stages o f stitch-and-glue construction, the sheerline is defined only by spreaders o r by bulkheads, and it can look a bit: scalloped. A lam inated sheer clam p stiffens and helps ho ld the span betw een the bulkheads fair. Later, the clamp will also serve nicely as the landing and fastening point for athwartships deck beam s and ultim ately for th e deck. By no tch ing the sh ee r clam p m em ber, you can let in the p re lam ina ted o r sawn-to- shape deck beams.

A b e tte r a rran g em en t uses longitud i­nal deck and cabin beams and elim inates the athwartship beams. This makes sense,

since the m iddle o f th e belowdecks area, especially in a small boat, gets the heaviest fore-and-aft traffic flow. If you have minimal headroom , athwartship beams m ean m ore head-knockers. In contrast, a couple o f stiff longitudinal beam s allow you to leave the cen te r 20 to 28 inches unclu ttered , with m axim um headroom . If carefully planned and crafted, longitudinal beams lookjust as p ro p e r in th e ir su p p o rtin g ro le as would athwartships beams. Furtherm ore , fairing the deck o r cab in top lines is m ade easier since there are fewer parts to fit.

In e ith e r construc tion , the sheer clam ps/stringers serve as s trong landing

Figure 10-7. A scalloped sheerline. A strong, stiff laminated sheer stiffener or clamp fairs betiveen hard spots caused by spreaders or bulkheads.

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D e v l i n ’ s B o a t b u i l d i n g

Figure 10-8. Notching o f deck beams into a sheer clamp.

Figure 10-9. A bow view o f Nancy’s China, with longitudinal deck beams let into a breast- hook forward and bulkhead aft.

points fo r th e deck. A sailboat has the additional strain o f its rig to contend with, but in all boats, dock rash, bumps, scrapes, gouges, bashes, and miscellaneous insults all seem to focus on the sheer and hull-to- deck jo in t—ab o u t 70 to 90 p e rcen t o f a b o a t’s wear an d tear, in fact. A strong sh ee r clam p heavily re inforces an d p ro ­tects this area.

Decks an d cabintops are also subject to heavy stress, so d o n ’t be tem p ted to m ake the decks too light. Ju s t im agine a clumsy, overw eight o af ju m p in g from a high fuel dock on to your deck. Lam inate the decks over the deck fram ing with sev­eral layers o f th in plywood. L am inated decks he lp tie th e deck fram ing to the sh ee r clam p, which in tu rn is tied to the sides o f the hull. A lam inated deck acts as a huge breasthook o r knee. I ’ve found that a V- to %-inch lam inate usually is a reason ­able com prom ise betw een adequate stiff­ness and excessive weight.

Stitch-and-glue boats use taped and fil­leted seams to both hold the hull together and bond the rest o f the internal structure. As a rule of thum b, I strive for a jo in t that is

Figure 10-10. A deck laminated from layers of thin plywood over framing.

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Figure 10-11. Approximate fillet dimensions fo r stitch-and-glue joints.

S c a n t l i n g s

as strong as the p ieces it bonds— but n o stronger.

If we could m eet that specification every time it would be perfect engineering. Som e say that L. Francis H erresh off’s design for a tum buckle was so perfect that w hen strength-tested, no on e part failed before the other. Failure occurred virtually sim ultaneously in every part. That is my ideal for a stitch-and-glue boat. Tailor fil­let thicknesses and weights and widths o f glass cloth reinforcing to achieve uniform

strengths. A fillet’s minimum depth should be equal to the thickness— or at least 75 percent o f the thickness— o f the plywood being bonded.

For example, a dinghy or small rowing skiff constructed o f %-inch plywood skin should have a fillet about 'A inch deep. The runout o f the fille t (the B d im en sion in Figure 10-11) should be double the thick­ness o f the plywood, or 'A inch from the jo in t ’s cen ter in this instance. This fillet helps to sm oothly transfer the strength

Figure 10-12. A view o f the forward cabin bulkhead Arctic Tern 23-foot sloop. Biaxial tapes are used in hull seams while woven cloth taping is used where seams will be visible on finished boat.

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D e v l i n ’ s B o a t b u i l d i n g

from one panel to an o th e r w ithout an abrup t interface. Layers o f fiberglass tape over the fillet should be tapered, allowing the fabric to s tren g th en the jo in t while gradually distributing loads and avoiding stress concen tra tions. In the case o f the skiff, 3- and 4-inch-wide, 6-ounce cloth lay­ers would be m ore than adequate. Do your prim ary re in fo rcem en t o f the hull seams and the bu lkhead and hull jo in ts on the interior for easier sm oothing and to avoid unsightly bulging exterior seams.

O n smaller boats, Volan-finished, 6- or 8-ounce fiberglass cloth cut in to tapes make strong, light joints. O n larger boats, I use biaxial fiberglass cloth tapes for jo in t re in fo rcem ent. By p lann ing ahead and knowing which areas will be fin ished b righ t, you can use woven cloth tapes in multiple layers for the visible areas ra ther than the off-colored biaxials. Use biaxial cloths for major hull jo in ts however, since they are significantly stronger, and usually h idden in the finished boat.

A typical fillet in a 30-foot boat with a skin thickness o f 5A inch w ould be %-inch

deep, on top o f which you would align 6-, 8-, and 10 inch-wide laminations o f biaxial cloth tapes. O n top of that, a 12-inch-wide layer o f 6-ounce glass cloth will help sm ooth the roughness o f the biaxial tape and allow you to fair and sand without cut­ting into the biaxial tapes.

Stitch-and-glue construction is differ­ent from traditional plywood construction in the bilge o r keel areas, which require a slight rabbet jo in t in the keel to attach the plywood skin to the b o a t’s backbone and fram ework. In the stitch-and-glue boat, keels, skegs, and all o th e r appendages should be bonded into place over the one- piece glass/epoxy sheathed hull to assure the hull’s integrity.

It is difficult if no t impossible to encap­sulate and seal heavy, thick chunks o f wood effectively with epoxy. I f m oisture is allowed in to the wood, the w ood’s d im en­sions will change as it swells and contracts with varying tem pera tu res an d with changes in the m oisture co n ten t o f the wood. This dim ensional instability results in incred ib le strain in the epoxy jo in ts,

Figure 10-13. Stitch-and-glue chine joints vary according to the size of the boat.

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S c a n t l i n g s

Figure 10-14. A keel o f traditional plywood construction, left, and one of multiple laminations o f Vt-inch material.

which ultim ately can lead to failure. The larger the p iece o f wood, the g rea te r the dim ensional change it undergoes. In gen­eral, I ’d say that no piece o f wood thicker than % inch can be adequately sealed with epoxy. If you have a thick keel to build, lam­inate many layers o f th in stock. If you pre­

fer to use thick dim ensional stock, attach it to the hull so it won’t tear the boat apart if it does change shape. I build a hull so its structural integrity is no t com prom ised by problem s with the stem o r keel. To me, these parts are rep laceable, b u t even so, they must be copiously sealed with epoxy.

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B u i l d i n g Cr a d l e s

In virtually every form o f boatbu ild ing , from trad itional wood to m o d ern fiber­glass, a lum inum , an d steel, th e bu ilder m ust provide som e form o f backbone fram ework o r com plicated m old aro u n d w hich th e boat is bu ilt. Only with stitch- and-glue, Scandinavian lapstrake, and dugout canoe construction can one avoid molds and frameworks.

No true stitch-and-glue design requires any form o f backbone framework or mold.

T here are, however, m any stitch-and- glue variations th a t requ ire some form o f in tegra l b u ild ing m old. Phil Bolger and Dynamite Payson’s tack-and-tape designs, fo r exam ple, use p re cu t bulkheads over which skin panels are assembled. As time passes we’ll probably see o ther quasi stitch- and-glue m ethods th a t use integral bulk­head fram ing over which hulls are assem­b led upside down. T h a t’s ju s t fine, since the m ethod w ould still take advantage o f com posite stitch-and-glue jo in ts—and if a partial mold makes sense o r makes the jo b easier, I ’m all for it. M ost o f my designs d o n ’t req u ire assembly fram eworks and are true stitch-and-glue designs, with the shapes o f the panels d ictating the final

shape o f the hull, assembled rightside up, then rolled over for bottom work when the interior is glassed.

W ith larger designs, the bu ilder m ust provide a cradle, bu t only to help keep the hull level and the panels in proxim ate rela­tionship while they are wired. T he cradle supports th e hu ll when the b u ild er m ust clim b in to install bu lkheads and o th er structures, and it keeps the panels from flexing o u t o f their true relationship with one ano ther. O ne alternative to a cradle is a set o f w ooden blocks, sawhorses, o r boatyard-type jackstands. Jackstands, in particular, are fairly inexpensive and effec­tive, and are what I use in my shop. But if you canno t reach th e cen terlin e o f your boat w ithout climbing into it, it’s easiest to build a simple cradle to efficiendy work in the interior. I f the boat is large enough to require this, it probably also needs support fo r tran sp o rt an d launching , an d if you p refer to no t use a trailer, the cradle could double as support fo r transport as well as m ain ten an ce an d storage. T h e cradle I built for my Arctic Tern is still in fine shape after eight years o f constant use.

A c rad le ’s m ost im p o rtan t purpose ,

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Figure 11-1. Jackstands support the stern of the 29-foot Means o f Grace. The chains pre­vent the jackstands from spreading apart.

Figure 11-2. A simple building cradle, which can be used for launching the boat as well as winter storage.

however, is to keep the b o a t level and square, especially when filleting and glass­ing the in terio r jo in ts. O nce cradled, it is immeasurably easier to level the boat lon­gitudinally and athwartships. During every stage o f bu ild ing, it is im p o rtan t to keep checking the levelness o f the hu ll struc­

ture; failure to keep it level will quickly lead to the m isplacem ent, m isalignm ent, o r even twisting o f in terior structures and a ru ined hull.

I p refer a cradle that uses longitudinal beam s as skids fo r the base, bu ilt up with crossmembers that touch and support the

Figure 11-3. Leveling a building cradle.

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hulls at stations 2, 5, and 8, based on a 10- station plan. If your plan does n o t specify the cradle dim ension details, you can easily figure o u t the cradle points from the sta­tion lines o f your design.

To build a cradle fo r a boat u n d e r 14 feet long, use 2- x 6-inch skids and 2- x 4- inch crossm em bers an d uprights. W hen m aking cradles fo r larger boats (up to 32 feet), I use 4- x 8-inch skids and 2- x 8-inch crossmembers and uprights.

Align the skid m em bers first. D eter­m ine th e w idth o f th e truck o r flatbed trailer you’ll be using to move and launch th e boat. My fla tbed is 5 feet 8 inches betw een th e rails, so the skids on all my cradles are ju s t a b it narrow er th an that. Build up the cross rails at the 2 /5 /8 station intervals an d ap p ro p ria te angles and lengths. T he m etal jo ist brackets available a t lum beryards are p erfec t fo r a ttach ing and stabilizing the crossm em bers, o r you can m ake scrap plywood gussets to re in ­force the cradle.

Place the uprights on top o f the cross rails. If you are building a keel boat, build th e uprigh ts in two sections so they sup­p o rt the hull p o rt an d starboard , leaving

Figure 11-4B. Reverse view.

sufficient room for the keel. O n larger keel boats, you m ight want to build two sets of uprigh ts, one fo r th e hull in a low (keel- less) position, and one for the hull with the keel in place, since m uch o f th e in te rio r w ork is accom plished before th e hull is

Figure 11-5A. End view o f building cradle for a powerboat hull.

Figure 11-5B. Notched building cradle for the keel o f a sailboat.

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ro lled over fo r ex terior glassing and keel attachm ent. The lower uprights will make in te rio r work easier by elim inating the additional clim bing that would otherwise be necessary.

Reinforce all o f the potentially move- able jo in ts in the cradle structure with ply­wood gussets. P ro tect the cradle surfaces that will com e in to con tact with the hull with layers of scrap carpet padding, nailing o r stapling the padding along the sides of o r underneath the uprights to prevent nail

heads from dam aging the boat. Use a good ex terior-grade house p a in t to p ro tec t all exposed cradle surfaces from weathering d u rin g o u td o o r storage. B uilt this way, your cradle can live a long and useful life.

For really big boats— 32 fee t and larger—you will have to increase the sizes o f your cradle tim bers substantially. Use your own ju d g m e n t an d rem em b er it is quite likely this cradle will live alongside the boat for a long time. I t’s worth doing a good jo b building it.

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This stage o f th e construc tion process involves stitching together the boat’s pan ­els using short pieces o f steel wire. Unless you’re building a really big boat, this is usu­ally do n e while th e hull is righ tside up. This is the heart and soul of the stitch-and- glue construction technique, and what sep­arates it from all o th e r m ethods o f build ­ing a w ooden boat. T he stitching process allows us to build a boat with no building molds o r framework, and it permits at least

Figure 12-1. Side panels project down past bottom panels.

a 30 p e rcen t red u ctio n in hu ll construc­tion labor relative to any o ther one-off con­struction m ethod.

T he wire stitches clamp together the large “pee ls” o f the stitch-and-glue boat un til epoxy com posite jo in ts can be app lied , w elding to g e th er th e plywood panels of the boat into its final form.

Since no real forms or building molds are used, the stitching phase is a critical step. We’ll use a simple V-bottomed single­

Figure 12-2. For high-speed powerboats, sides should extend even farther past bottom panels to accommodate chine fla t.

S t i t c h i n g U p t h e H u l l

chine hull to illustrate the process.A couple o f basics: First, I always over­

lap the side panels down past the bottom panels, thus allowing the lofted chine edge or curve o f the bottom panels to define the true chine o f the boat. This m eth o d also allows the side panels to p ro tru d e below the chine o f a high-speed pow erboat that requires a built-in chine strip or flat. I also feel that stitching is easier and the results are m ore fair w hen the sides overlap the bo ttom panels, because the side-panel ends can be sprung in and out and shifted up and down to adjust to the bottom pan ­els as you stitch.

Begin by laying o u t the two bo ttom panels, interior face to interior face, on the floor o r on sawhorses. While these panels are clam ped together, scribe a stitch line that follows their keel edges but is set back by the thickness o f the plywood plus % inch. For example, if the plywood is K-inch thick, the stitch line m ust be Vs inch away from the edges. Using the scribe line along the keel as a sewing line, drill a series o f holes ab o u t 6 inches ap a rt a long the length of the keel edge, through both pan ­els. W ithin 2 to 4 feet o f each end , where the greatest stress occurs on the stitching,

drill the holes every 2 inches. Make sure the holes are p erp en d icu la r to the ply­wood surfaces. Next separate the two pan­els and bevel their inside keel edges sepa­rately, using a block plane or rou ter set at 45 degrees. Bevel only to the halfway point o f the plywood’s thickness. If you were to a ttem p t to align the panels w ithout the bevel, you’d find that the keel edges would overlap o r one pane l m ight ride u p or down alongside the o ther panel. In either case, the resu lting keel line w ould be unfair. T he bevels give us fric tion to the jo in t, allowing us to h o ld p ro p e r align­m ent m ore easily.

P repare your wire stitching kit ahead of time. Use a tray or bucket with com part­m ents fo r pre-cut 6-inch lengths o f steel wire, a sturdy pa ir o f lin em an ’s pliers, a drill with a X-inch bit, and a small hammer. You may want to ask a friend to assist you in the stitching process.

After the panels are drilled, set them on sawhorses with the 45-degree beveled faces meeting and facing inward. If aligned correctly, the d rilled holes will line up since the m ating panels were drilled one on top o f the other. S tarting at the bow end, thread the wires individually through

Figure 12-3. Scribing a stitch line on plywood.

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Figure 12-4. Beveling is essential for proper alignment o f bottom panels.

the holes, twisting them to snug up the panels. Work your way tow ard the stern , stitching the keel line seam. If necessary, use a dowel the same d iam eter as the ply­wood thickness to twist the wires over. After breaking a handful o f wires o r tearing out a few holes you will learn how snug you can

tighten the wires. The wire stitches should have en o u g h slack to allow the bottom panels to spread and still fit snugly. If the

Figure 12-5. The stitching kit: tray, precut wire sutures, lineman’s pliers, and a drill motor.

Figure 12-6. Wire stitches in place on the book- folded bottom panels. Note the bevels on the inboard edges o f the panels and the tautness of the wire twists.

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Figure 12-7. A dowel or pencil the approximate thickness o f the plywood will act as a form around which to twist the wire stitches.

stitches are too tight, the bo ttom panels will n o t spread properly, and if they’re too loose, you’ll get a sloppy and p o o r fitting seam with an unfair keel line.

Move the stitched (bu t still stacked) bottom panels to your assembly area, and sp read them op en like a book. They should open to about 160 degrees. To hold them in the spread position, cut a piece of wood to the w idth o f one b o ttom panel. This is the bottom spreader. K eeping this spreader horizontal, attach it with a loop of rope o r wire a ro u n d its m id p o in t to any wire stitch in the keel line, then tighten the loop by twisting it with a stick to pull down the spreader until the correct bottom posi­tioning is realized. This m ethod is particu­larly useful to som eone working alone.

O nce the bo ttom panels are posi-Figure 12-8. With the bottom panels stitched along the keel line, they can be spread open.

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Figure 12-9. On a larger stitch-and-glue hidl the panels must be spread gently to avoid tearing stitches or plywood edges.

tioned and spread, bevel the outside chine edges with a block plane. This is also the tim e to co n ten d with the transition jo in t, which is unnecessary in fla t-bottom ed o r shallow V-bottomed boats, bu t is required

Figure 12-10. A batten can help spnead the bottom panels prim to stitching the sides.

to sm ooth the bow portion o f the chine of boats in which the V-shape is pronounced.

A short explanation o f this transition jo in t is in order. T he chine, o f course, is the intersection o f the bottom panels with the side panels. During the wiring process, the side panels overlap the edge o f the bot­tom panels. As the panels are pu lled together, they have the freedom to curve fairly into the boat’s profile. But in the bow sections, the deadrise angle o f the bottom panels increases, an d the ch ine angle between bottom and side panels gets pro ­gressively larger, until it is no longer feasi­ble fo r the side panel to overlap the bo t­tom panel. At this p o in t ( just aft o f the s te m /c h in e in tersec tion ), in o rd e r to achieve a fair ch ine curve an d avoid an obvious overbite o f the stem in the profile, we m ake a shift in the seam from a lap

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Figure 12-11. With no transition joint, the stem shows an overbite.

jo in t to a bu tt joint. This is done by cutting a no tch in the forw ard en d o f th e side panel to com pensate fo r the ab ru p t change o f the chine as it fairs up with the side panel into the stem. Your plans should indicate the length o f the transition jo in t fo r th e design you are build ing . I g en er­ally use 12- to 18-inch transition jo in t lengths fo r boats up to 10 feet long, 24 inches for boats 11 to 17 feet long, 36 inches for boats 18 to 25 feet long, and 48 inches for boats 26 to 40 feet long. The only objective of these transition joints is to allow the panels to jo in m ore fairly the entire length o f the boat.

Begin setting up a transition jo in t by marking and cutting a notch the specified transition length from the forward chine o f the side panels. I cu t the no tch deep enough to match the thickness o f the ply­wood bo ttom panels plus % inch, which should allow us enough height to keep the transition jo in t fair.

Next, after the two bottom halves have been stitched along the keel line and spread, bu t before planing the chine edge, go to the forward end of the bottom panels. M easure back from the stem in tersection the length of the notch that was previously cut from the side panels, and m ark it on the bo ttom panels. W ith a handsaw, m ake a small cut on that m ark at the approxim ate angle at which the side panel bears to the bottom panel in the transition area.

Now go to the stern end o f the bottom panels and plane the entire chine edge up to the saw cut, bu t no t past it; this is the point at which the side panel changes from ru n n ing down alongside the bo ttom pan­els to jum ping up and abutting the bottom panels as in the illustrations. Make sure to p lane only to the cut u p p e r edge o f the bottom panels; any farther and you would radically change the design.

Next, lay th e two side panels face to face, making sure they are on a completely flat surface. Scribe a line along the chine edge of the panels ju st as you scribed a line along the keel edge o f the bottom panels, % inch plus the thickness o f the plywood from th e edge. W hile the panels are clam ped together, drill the stitching holes ab o u t 4 inches apart. W ithin 24 to 48 inches o f the panel ends, where the great­est strains will occur, drill th e holes 2 inches apart. I always drill as m any holes as I th ink m ight be necessary in the worst case to stitch up the boat. While stitching the panels you may find th a t you d o n ’t need wire ties in all the holes; even so, the p red rilled holes serve as a gu ide d u ring the stitching process, and i t’s a lot easier to drill holes accurately w hen th e panels are flat. By drilling both side panels simul­taneously, there is symmetry to the stitches. Separate the two side panels, and bevel a 45-degree angle on the inside of the stem edge o f b o th panels to aid a lignm ent

Figure 12-12. Stem profile with an adequate transition joint.

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bow end

Figure 12-13. Transition jo in t details.

there, ju s t as you d id on the keel edges of the bottom panels.

At this p o in t we have p red rilled holes in th e ch ine edges o f th e side panels, b u t n o t in the ch ine edges o f the bo ttom pan ­els. I wait to drill those holes until I am actu­ally s tarting to stitch o n the side panels. T h a t way I can easily align ho le locations and clamp the hull panels m ore accurately. Drill only one o r two holes at a time in the bottom panels, setting them back from the edge by about the thickness o f the plywood. T he easiest way to wire the chine lines is to push the wire into the predrilled side panel ho le from the outside, b en d it in to a U- shape, an d re tu rn it th ro u g h th e freshly d rilled m ating ho le in the bo ttom panel. Drill only a few holes at a time in the bottom panel, directly opposite the side pane l holes, and stitch as you go along each side. Start stitching the side panels from the bow end first. As you move toward the stern, set and tighten the wires, trying to set up each stitch with even tightness and force.

If you are right-handed, start with the s ta rboard side p an e l a t th e bow. L eaning

Figure 12-14. Transition jo in t stitching details.

over th e side, you shou ld be able to drill holes in the bottom panel to ensure that the hole is opposite the predrilled hole in the side panel. If you have a helper, have th a t p erson h o ld th e en d o f the side pane l in

Figure 12-15. Notch height o f transition joint cut in chiTie edge o f side panel.

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alignment. And with simple guidance from the stitcher they can move the panel up or down or in and out to allow for good align­m ent. If you are w orking alone, and the boat is quite large, you may need to suspend the panel from a rafter or clamp a hoard to the end to brace the panel from the floor. E ither way, with adjustm ents to suspension o r to the brace, you should be able to stitch together the panels. Com plete one en tire side before moving to the o ther side. When attach ing the p o rt side panel, again work from stem to stern. You m ight find it help­ful to fasten several wires at the top o f the stem line ju s t to ho ld the two side panels u p righ t an d in p ro p e r a lignm en t while stitching up the rest of the chine.

Constantly check the fairness of the seam throughout the process. All the wires should en te r the side panel flush with the

top edge of the bo ttom panel; if n o t you will have a loose o r unfa ir ch ine line. W hen you twist the wires snug, make them uniformly tight.

After both sides are stitched, fully wire the stem line from bottom to top, making sure to m ain tain side-to-side alignm ent and the symmetry o f the bow. T hen secure the transom, wiring o r using nails or screws to position it. Your hull is now stitched up b u t still in a som ew hat m isshapen form that we’ll cover in the next chapter.

A few no tes ab o u t stitching. I have lea rn ed the h ard way th a t u ltim ately no part o f the wire should be left in the stitch points in the finished boat. As m uch as you m ight th ink it would be easier to simply trim the stitching flush with the panel sur­faces an d glass over, beware! All m etals contract and expand at different rates than

Figure 12-16. Side panel stitching on a larger design. The hull is large enough to allmu the interior boatbuilder to drill and poke wire stitches through to the outside, where they are twisted snug. The worker to the right adjusts the side panel for proper alignment.

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D e v l i n ’ s B o a t b u i l d i n g

Figure 12-17. Proper and improper alignment of side and bottom panels.

wood and epoxy, and sooner or later, these wire rem nan ts will work th e ir way o u t th rough the surface o f your paint and fin­ish. I use m ild steel wire (16 gauge) for my stitch ing because o f that. Steel wire is tough en o u g h to ho ld your panels together, yet can be extracted fairly easily. Baling wire purchased from a local hard ­ware store is cheap, easy to use, and readily available. O n some larger boats, though, I

have found that baling wire is n o t consis­tently strong enough to hold the big, stiffer panels. For those boats, galvanized electric fence wire (12.5 or 14 gauge) is the c h e a p est an d best alternative. You can buy it from a feed store in large spools. Try it; I think it works great.

C onsidering all th e ideas being bandied about, stitching seems to be a fas­cinating process that has captivated many good m inds in search o f ways to m ake it easier. And while any good idea on fasten­ing panels is fine with me, the point is, the stitching process is easy. Go ahead and use m onofilam ent fish line, or nylon cable ties, or staples, nails, or anything else. Just make sure that you can get those stitches ou t of the seam before the boat’s finished.

W ire stitch removal is covered in C h ap ter 16, bu t a h in t o f what to expect will be useful here. T here are two choices for removing the wires from the joints, and I use either depending on my work sched­ule and the size o f the boat. T he first is to place small epoxy fillets between each wire stitch on the interior seams with a fast-cur­ing thickened epoxy resin. W hen those fil­lets cure, pull ou t the bulk o f the wire ties, leaving in ju st a few in the high-stress areas o f the hull.

Your o th er option is to fillet and tape completely all the seams, disregarding the wire stitching. W hen th e epoxy cures, rem ove th e wire stitches by applying enough heat to the wire to cause the epoxy to release its tenacious hold on the metal, an d pull the wire o u t o f the jo in ts with a set o f pliers. E ither way works fine and shouldn’t be a problem .

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B u l k h e a d s , Cl a m p s ,

a n d Fl o o r Ti m b e r s

B U L K H E A D S

Although a stitch-and-glue boat primarily starts with the hull skin and works inward, it m ust also rely on in terio r structures for

add itional hu ll support. T he sim ple dinghy gets su p p o rt from seat thwarts, stern knees, breasthooks, and gunwales. In a large boat, a com plicated grid o f athwartships (sideways, o r p erpend icu lar to the cen terline) an d long itud ina l (lengthwise, o r parallel to the centerline)

Figure 13-1. Perspective view o f a 22-foot catboat built with stitch-and-glue construction. Every component serves a structural function. (Stephen l . Davis)

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Figure 13-1A. View o f the same 22-foot catboat, built using traditional construction methods. Note additional framing. (Stephen l . Davis)

bulkheads provides this critical support. These bu lkheads n eed to be fitted in to place, and b o n d ed with the sam e type o f epoxy fillet/fiberglass tape seams that hold the hull panels together. G reat care must be exercised to ensure that the bulkheads are loca ted with precision and in p ro p e r relationship to the sheerline and waterline o f the boat.

If you are bu ild ing a sizable boat, before you can tu rn the boat upside down fo r ex te rio r shea th ing , you will n ee d to reinforce and stiffen it by installing a few o f th e m ajor athw artships bulkheads. You need not install longitudinal bulkheads yet (see C hap ter 23), nor need you install all the athw artships bu lkheads at this time; you can postpone some of this work if you wish. But the m ajor athw artships bulk­heads should go in now. N ot only do they re in fo rce an d stiffen th e hull, b u t these th ick bu lkheads may receive fastenings

th rough the hull sides, an d you want the heads o f those fastenings to be sealed by the exterior sheathing or by exterior cold- m olding. T he sm aller th e boat, th e less likely are the bulkheads to receive through-hull fastenings, an d the less nec­essary they are to stiffen the hull p rio r to tu rn in g it upside down. So th e re is ju d g ­m en t involved in dec id ing how m uch o f the bulkhead grid you need to install now and how m uch will keep until later. O n my designs, I often label bulkheads according to their recom m ended time o f installation: those necessary to install befo re rollover and those th a t can wait fo r la te r installa­tion. If your plans d o n ’t include this infor­m ation, b e tte r to e rr on the safe side and bond in those m ajor bulkheads nearest to stations #2, #5, and #8 as soon as possible.

Before starting the seams, you’ll need to ad just an d level the stitched-together hull. I f you are correctly aligned to the

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Figure 13-2. Position major support bulkheads as near as possible to stations #2, #5, and #8.

designed w aterline, you will be level in bo th the long itud ina l (fore an d aft) and athwartships (lateral) orientations. If your hull is ou t o f level, the bulkheads may no t contact in the locations shown on the plans.

Most stitch-and-glue plans will show a lengthwise scale o r ruling line m arked with athwartships hull bulkhead positions. Your hull m ust be positioned properly, with

sh ee r beam s o r sp readers in place (see C h ap te r 12) to set up the co rrec t design shape. If your sheer spreaders are too wide o r narrow, your hull will be misshapen. As you spread the hull to its p roper beam the bow will rise o r fall, and as a resu lt the athwartships bulkhead positions, which are m easured aft from the bow, will change. T herefo re , go th ro u g h each m ajor bulk­

8 inches. Measuring from the transom edges and the bow to your shop floor or some other level surface should produce the same difference.

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Figure 13-4. The boatstands under the stern of this 29-foot Black Crown poiverboat can adjust fo r the twist of the large transom. The Black Crcrwn is multichined, and the upper side panel has not yet been attached. Note the spreaders, which will be used at both the intermediate and the upper sheer.

head , sp read ing the hu ll beam to its p ro p e r w idth as you move aft from the stem, to double-check its location and its athwartships beam, o r width.

After sheer spreaders are positioned at each m ajor bulkhead station and the hull has been spread at the sheer to its p roper beam, you are ready to verify the bulkhead inform ation. This is very important: Even i f your designer has given dimensions and sizes for all bulkheads, double-check the bulkhead dimen­sions anyway. T h e characteristics o f ply­wood differ, and hull panels can bend dif­ferently boat to boat. I t’s easy to check, and this will avoid a lot o f grief later on.

For exam ple, my shop has built two

S u rf Scoters side by side, with one hull stitched o f 7-ply, 12mm plywood and the o th e r stitched o f 5-ply, 12mm plywood. T h e b u lkhead dim ensions en d ed up slightly d iffe ren t because the 7-ply hull stock was stiffer, and the re la tionship betw een these hull panels differed from the in teraction o f the m ore flexible 5-ply b o a t and panels. T he d ifferences were m ost noticeable in the bow and stern sec­tions: Stiffer wood means less shape, m ore flexible wood means m ore shaping ability, so you may n eed to adjust the bulkheads accordingly. I f your bu lkhead sizes differ dramatically from the plan, however, you should stop and review all your prior steps

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for accuracy, checking particularly that the hull setup is level and there is no twisting in the hull.

You will also n eed to check your stitched-up hull fo r long itud ina l twisting. T he best check is to m easure back d iago­nally from the tip o f the stem to each top cor­n e r o f the transom . If your transom had been screwed o r stitched in place symmetri­cally, that diagonal m easurem ent should be exactly the same p o r t an d starboard . I f it varies you m ost probably have a hull that is somewhat twisted. I t ’s easy to adjust this by p lacing small legs u n d e r the transom and w edging un til the d iagonal m easu rem en t

is the same. A final check with a Smartlevel, spirit level, o r w ater level will give you the confidence that your hull is true.

If your hull flexes and moves too m uch w hen you are clim bing abou t checking bu lkhead m easurem ents, you can always tab areas o f the ch ine and keel with a bit o f wood flour and epoxy. This stiffens the b o a t and allows you to work with fewer flexing problems. Place the tabs from 8 to 12 inches apart a long the chine lines and keel lines. Be careful n o t to place tabs in the way o f the in tersections o f the bulk­h ead positions, as th a t only makes your m easuring jo b that m uch m ore difficult.

Figure 13-5. Waterhose leveling o f a hull. Use clear vinyl hose.

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To verify each bulkhead position, s tre tch a tape m easure from th e stem along the cen terline o f the boat, then lay a ba tten from sh ee r to sh ee r a t the bulk­head location, perpend icu lar to the tape m easure. Lightly m ark the fro n t edge o f the ba tten w here it in tersects th e sh ee r both port and starboard, along the tops of the plywood side panels w here they in ter­sect the batten. Now hook the end o f your tape m easure over the stem centerline of the hull an d move the tape side to side, m easuring th e diagonals to each o f the m arked bu lkhead ends. These two m ea­surements should match. If they a ren ’t the same and you are sure th a t the w aterline and athwartship alignm ent is correct, your batten wasn’t perpendicular to the center- line tape.

Adjust your b a tten by averaging between the port length and the starboard length. For example, if you measure 10834 inches on th e p o rt d iagonal an d 109% inches on the s tarboard diagonal, you need to move the m ark aft on the port side by half the difference, and forward half of the distance on the starboard side. In this case, the difference is 1 inch, so both sides will have to move Vi inch so they m easure 108% inches on th e d iagonal from the stem. W ith the batten aligned to the new sheer markings, recheck the b a tten ’s half­beam m easurem ent from the centerline to see w he ther it still m atches the design’s bu lkhead sheer d im ensions. If all these m easurem ents check out, rep ea t the process at the next bulkhead station.

W hen build ing a m u ltich ined vessel such as th e Black Crown, you m ust go th rough this m easuring p ro ced u re no t only at the sheer, but also at the tops o f the lower side panels (also known as bilge pan­els). With the Black Crown, you’ll note two

sets o f longitudinal m easurem ents to the bulkhead positions, because the stem rakes forward approxim ately 2 inches from the top o f the bilge pane l to the top o f the u p p e r side panel (the tru e sheer). You’ll also note two sets o f m easurem ents for the beam inside the planking, one for the top o f the sheer panel and one fo r the top of the bilge panel.

O nce all the m ajor bulkhead positions are m arked at th e top o f th e side panels an d th e p ro p e r beam s have b een estab­lished at each b u lkhead station with spreaders tacked in p lace, lay a straight, stiff batten from side to side on top o f the sheer to intersect bo th sheer marks. Drop a p lum b bob down and m ark its intersec­tion with the keel centerline and with each chine line. Then use a smaller straightedge to draw lines on the hull panels from the m ark on the s tarboard sheer, to the star­board chine, and from the starboard chine to the centerline o r keel mark. Repeat on the p o rt side. These lines define the bulk­head placem ent, so you can quickly check your actual bu lkhead dim ensions against the designed dim ensions. Using this easy m ethod o f locating and drawing in the bulkhead placem ents, you have the capa­bility of positioning almost any piece of the boat in th e hull shell, thereby quickly defining its actual shape.

M easure th e bu lk h ead dim ensions

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Figure 13-7. Marking bulkhead locations using a plumb bob and a stiff batten.

from sheer to sheer (the width o f the boat inside the plywood sides), checking d iat it m atches the bu ild ing plans exactly. This width should no t vary from your plans since it was set up by you with spreaders. Next, m easure the inside w idth from ch ine to chine, no ting this dim ension on the bulk­head sheet o f the plans. Now measure down perpendicular from the straightedge to the chine, an d then to the cen te rlin e o f the keel, in each case ensuring th a t you m ea­sure down from w here th e p lum b bob string was held to the batten. Com pare the two widths an d two heights you have ju s t m easured with the designed dimensions on the plans. T hough there may be some small discrepancies due to the stiffness of the hull planking, there should be no change in the width at the sheer, since this d im ension comes from the spreaders you have p u t in place. If the change o f any o f the “B,” “C,” o r “D” m easurem ents is dram atic , on the

order o f 1 inch o r m ore, double-check the bulkhead p lacem en t and the levelness o f the hull to the designed waterline.

O n som e designs you m igh t confron t an angled bu lkhead . T h e app roach fo r

A:Width at sheer(os set by builder from plan dimensions).

B: Width at chine(as measured from stitched hull).

C: Depth from sheer to keel line (as measured from stitched hull).

D: Depth from sheer to chine (measured from stitched hull).

Figure 13-8. Key bulkhead dimensions.

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these is similar, except that you will no t be able to use a plum b bob for picking up the points on the chine and the keel. Instead, make up a large angle-gauge with a couple o f straightedges an d a C-clamp. Set your gauge to the designed bulkhead angle from the building plans, then lay a wide (approx­imately 10-inch) board on the flat from sheer to sheer, and lay your angle-gauge on that. Extending the leg o f the angle-gauge with a clam ped straightedge as necessary, m ark the intersections at the chine and the keel. This locates the bulkhead on the hull panels. C heck the resu ltan t d im ensions against the plans as for vertical bulkheads.

A nother m ethod o f checking is to set up a Smartlevel an d shoo t down to ch ine /keel points at the p roper angle.

W hen you are satisfied with your bulk­head measurements, draw in the bulkheads on your plywood stock. The plans may state the grain orientation and should note— if a bulkhead is wider than 4 feet o r taller than 8 feet—where the bu ttjo in ts should lie. (If your plans d o n ’t show that in form ation , you can work it ou t on your own.) Mark the centerline o f the bu lkhead first, since the half-beam dim ensions are taken from the cen terline outward. Next, m easure verti­cally from the base o f the bulkhead to the heights (on the cen terline) o f the chine, sheer, an d any o th e r p o in t tha t is to be no ted . With a fram ing e r drywall square, draw the necessary horizontal lines. Mark the half-beam at the chine on the horizon­tal chine line (mark both sides if you are lay­ing out the full bu lk h ead ), and repeat the process to locate the sheer half-beams. Now connect the centerline o r keel depth mark to the chine and sheer marks. The bottom panels may have some outward curvature betw een the ch ine an d the keel, particu ­larly in the forward ha lf o f the hull. If so,

Figure 13-9. Bulkhead scribing. For angled bulkheads use a large bevel gauge made from scrap stock and shoot projections o f the angle given in the plans from points at the sheer to the keel and chine.

lay a straightedge in the hull from keel to chine, m easure the d ep th o f the outward curvature, transfer an d draw in that am o u n t o f curve on the bu lkhead stock before you cut out the bulkhead. If you for­get this step, you can fill in the gap later with epoxy resin and fillers. Draw in the deck cam ber between the sheer half-beam marks as described below.

Like the floor tim bers (which we will install la ter), the bulkheads m ust be lim­bered to allow water to drain to a central low po in t in the bilge where it can be pum ped out. I usually resist the tem ptation to com­partmentalize any one area o f the boat, and always give water an easy path to the bilge. The only exception is the engine box, which must be separate since it is neither legal nor environm entally sound to pu m p engine- related petroleum products overboard with bilge water. Isolating the engine com part­m ent will contain fuel oil o r lubricant spills until they can be cleaned up with oil soak rags o r sponges and disposed o f properly.

After cutting out the bulkhead, check for proper fit in the boat. You may want to

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Figure 13-10. With a pencil laid fla t (parallel) to the hull sides on bottom, mark a line on the bulkhead being fitted to produce a much sweeter fit.

scribe it into perfect position with this sim­ple b u t accurate m ethod: With your pen ­cil laid flat on the hull panel and the bulk­head in place, draw a line a ro u n d the perim eter o f the bulkhead. This gives you a scribeline set back about % inch from the bulkhead edge. A bit o f block plane work on th e h igh spots outside the scribe line should allow the bulkhead to fit perfectly.

All the m ajor bulkheads should be carefully m easured and cut ou t before any in te rio r tap ing is do n e on boats longer than 15 feet. Checking m easurem ents for beams and heights and aligning these mea­surem ents to the designated plan d im en­sions will avoid m iscutting o f bulkheads and the ir adjacent parts. Before the bulk­heads are installed, th e ir edges and the contacting areas o f the hull panels should be carefully sealed with epoxy. I usually coat the raw edges o f the bulkheads first, then climb into the hull and coat the con­tacting areas on the hu ll panels. I then recoat the bulkhead edges, since the end grain o f the plywood tends to absorb epoxy m ore readily. I place the bulkheads in the boat while the epoxy is still wet. P in each

bulkhead in place with a few stainless steel sheet-m etal screws (a t least two o r th ree p e r hu ll panel) th ro u g h the panels and in to the b u lkhead edges. T he screws will hold things in place until the epoxy sets up.

T he bulkheads are then b onded into place with the same epoxy fillet and taped seam jo in ts th a t bo n d the hu ll panels together. T he process is the same: First coat the areas to be taped with un th ick ­ened epoxy resin to ensure there will be no resin starvation in the jo in t. Next apply the epoxy /w ood flour fillet, and th en apply the fiberglass tape layers using un th ick ­ened epoxy. I deal m ore extensively with glassing in C hapter 14.

O n a larger boat, an d always on one with a cabin, I fit all the m ajor bulkheads in place before starting any seam taping on the hull panels o r th e bulkheads. It is m uch easier to check th e dim ensions o f the bulkheads w ithout having a filleted taped seam in the way, and your taping or glassing o f the seams can be do n e in shorter, easier-to-handle segments after the m ajor bulkheads are in place. I p re fer to do the majority o f the fitting in one session and the majority o f the epoxy seam taping in one session. This makes less o f a mess, and there is virtually no repeating of steps.

I also attem pt to avoid installing bulk­heads that extend m uch above the sheer of the boat a t this stage. Remember, the ini­tial hu ll stitch-up an d bu lkhead work is being done with the hull right side up. We want to add any in te rio r s tructural m em ­bers that will strengthen the hull p rio r to tu rn in g it over, b u t we d o n ’t want to add structures o r parts th a t will m ake ro lling the boat over m ore difficult to accomplish. Bulkheads th a t ex tend m uch past the sheer certainly do this. A good example is the S urf Scoter’s aft pilothouse bulkhead,

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which extends almost 36 inches above the sheer. T hat m eans the boat would have to be blocked up an ex tra th ree feet while upside down for the exterior work.

The soludon to bulkheads that extend significantly above the sh ee r can be to build th e bu lkhead in two halves— one from keel to sheer, and th e second from the sheer up. A nother solution is to install two bulkheads, one ju s t in fro n t o f the other. In the S urf Scoter, a cockpit bulk­head betw een th e keel and th e sheer

serves as a landing place for th e cockpit sole and cockpit side decks. After rollover, the aft pilothouse bulkhead is added ju st in front o f the cockpit bulkhead, providing a landing for the side decks o f the boat. I fasten the two bulkheads to g e th er with screws, and build an epoxy /tape seam on the after side of the cockpit bulkhead and the forward side o f the aft pilothouse bulk­head. This m ethod is strong and easy, and provides landings fo r structures bo th in front o f and behind the bulkheads.

Figure 13-11. Double bulkheads can be used on boats like the Surf Scoter, whose high bulkheads make rollover and exterior sheathing inconvenient The lower bulkhead (cross hatching) is installed before rollover, the higher section after sheathing.

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STEP-BY-STEP SUMMARY

OF BULKHEAD FITT1JVG

PROCEDURE

Level the stitched hull with the designed waterline.

Level the hull athwartships to the design waterline.

Mark the major bulkhead locations on the top of the sheer on both sides.

Lay a straightedge sideways across the boat, intersecting marks on sheer.

Drop a plum b bob to align vertical bulk­heads and mark the bulkhead posi­tion at the chine o r chines and at the keel centerline.

Measure the vertical distance (heights) from the straightedge to the chine and to the keel centerline at the loca­tions m arked in preceding step.

Measure the sheer and chine beams (widths) to the inside o f planking.

Check these m easurem ents against your plans, and correct the bulkhead dimensions as necessary on your plans.

W hen you are satisfied with your actual dimensions, lay out the plywood stock for the bulkheads.

For each bulkhead, draw in the center- line.

Mark the sheer height on the bulkhead centerline.

Mark the chine heights on the centerline.Draw horizontal lines through the height

marks, and along these m ark off the half-beams at the sheer and chines.

Draw the deck cam ber as described below.Draw in any o ther dimensions o r details

indicated on the plans.Connect the dots and cut out the bulk­

head.

Position the bulkheads in the boat and pencil-scribe to adjust into place as necessary.

Coat the edges o f the bulkheads (and the hull where the bulkheads will land) with epoxy, and d rop the bulk­heads back into the hull, making sure the marks at the sheer, chines, and keel align to the p roper side o f the bulkhead (usually the aft side).

Pin each bulkhead into place with a minim um of two o r three screws per hull panel. Screw holes can be pre­bored from inside the hull before final placement o f the bulkhead to aid the positioning o f the screws.

A fter all m ajor bulkhead pieces are in place and the epoxy has cured , fillet and glass the hull-to-bulkheadjoints.

DECK CAMBER

You will note on your plans that there is usu­ally a deck cam ber called out, indicating the am ount o f crown in the deck. Typically this crown varies in height in relationship to the width of the boat at the point.

W hile the he igh t varies accord ing to w idth, no te that bo th m easurem ents in Figure 13-12 are taken a long the same cam ber ruler. (Som e designs may have com plex cam ber, which varies a long the length o f the boat, but I find this a tedious and no t very necessary detail, on decks in particular.) O n my own designs I generally use a consistent cam ber ruler, o r 1 revert to ano ther m ethod for establishing the cam­ber, for exam ple w hen a cabin to p ’s fo r­ward crown differs from its aft crown.

T h ere is a p ro p e r m ethod to lay o u t for constan t cam ber an d a couple o f eas­ier methods. If you’re a skilled draftsman,

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Figure 13-12. Deck camber ruler. Note the differences in the heights o f the bulkhead, crowns as the width o f the beam changes.

you can loft it— or you can use this “ch e a te r” m ethod . C ut o u t two stiff, straight battens, each abou t 6 inches longer than the width o f the boat. O n a sheet o r sheets o f plywood, lay o u t a grid with a straight line equal to the m axim un beam o f the boat; this is your baseline. Drive a nail at each end o f the baseline. At the baseline’s midpoint, draw a perpendic­u lar line and m ark the overall he ig h t o f the stated cam ber, driving a nail at tha t point. Now lay your two battens against the centerline nail and each baseline nail. Join the battens where they intersect with two

or m ore nails, then pull out the centerline nail. With a pencil in the crotch (see Figure 13-13) and the battens in full con­tact with the baseline nails, you can draw a true camber. Cut ou t the plywood pattern and use it as a tracing p a tte rn on your bu lkhead layouts— m aking sure the pat­te rn ’s m idpoint matches the centerline on the bulkhead.

S H E E R C L A M P S

While the chines, keel line, and bulkheads can be easily bonded together witii epoxy/

Figure 13-14. On a sailboat with forward and aft cabin bulkheads, use longitudinal cabinlop beams to compensate for the differences between the two crowns.

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taped seams, there isn’t a convenient way to fasten the hull-to-deck jo in t (with com­posite g lass/epoxy jo in ts ) . Lam inated sheer clamps provide stiff, fair landings for the decks. In open boats with unprotected sheers that are n o t braced to any o th e r structure, it is im portan t to reinforce that a rea with gunwale sheer clamps. All told th e re are several types o f sheer clamps; we’ll discuss the gunw ale/clam p first.

G lued securely on the sheer o f an open skiff, dinghy, or open rowing boat, a

Figure 13-15B. Spacer blocks on the inwale o f a gunwale/clamp.

gunw ale /c lam p looks good and finishes off the boat nicely. If the open boat is a sail­ing design o r will be subject to a great am oun t o f strain from oarlock fittings, I glue small spacer blocks to th e sheer before fastening an inwale into place. This m akes the inwale act as a g ird e r and fu r­ther stiffens the clamp.

T he second type o f sh ee r clam p is properly term ed an exterior clamp, and it will stiffen and fair the sheer o f a hull that has decks and bulkheads. While the chine is held fair in re la tionsh ip to the bo ttom o f th e boat, th e sheer is not. If th e re are bulkheads for interior structures, the sheer may actually stretch around the bulkheads, creating a somewhat scalloped look when viewed from above (see F igure 10-7). I d o n ’t often use an exterior clamp on boats longer than 24 feet, however, because i t’s hard to m ake a clamp structure with ade­q uate su p p o rt for th e strains o f a larger boat. T he decks m ust fasten over the top ­side p lank ing and the clam p, and w hen decks are shea thed , th e clo th m ust wrap over and down on to the face o f the exte­rior clamp. Unfortunately, because o f the am ount o f glass that needs to be applied to reinforce this edge, it is difficult to bright- finish the sheer of the boat, as can easily be done when a gunwale clamp is used.

I use a variation o f the exterior clamp on my Lichen design th a t incorporates a wider sheer clam p section, 4 inches wide and X inch thick. To this I attach a smaller, %-inch x 1-K-inch teak rubrail at the top of the sheer to finish o ff th e jo in t and p ro ­tect it from chafing wear.

A third type o f clamp, for boats longer than 18 feet, is an in te rio r clam p lam i­na ted from two o r m ore layers o f %-inch d im ensional wood fastened th ro u g h the topsides o f the hull. Fasten the decks

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securely to the in terior clamp and run the sheathing over the deck edge onto the top- sides sheathing. A small hardwood rubrail can then be fastened at the sheer, just below the roundover at the deck edge, pro ­tecting the sh ee r from chafe. If you want toerails, they can be fastened over the deck in to the clam p w ith long, coun te rsunk screws.

Always install both port and starboard sheer clam ps d u rin g the sam e work ses­sion. These clamps are stiff, and can pull a boat ou t o f shape if the work isn’t balanced side to side. Also try to ru n these clamps full leng th a long the sheer, th rough notches in the bulkheads, so they will pull the plywood sheer into a fair curve. Often, I will lam inate one layer at a time to make the clamp easier to handle, using C-clamps and fasteners to ho ld it in place until the epoxy sets up. I glue in a layer to p o rt and one to starboard, clean up the excess glue, and the next day glue in the second layer, port then starboard.

M ultichined vessels like the Surf Scoter use an interm ediate sheer clamp system to pull the edge o f the hull panels into fairness and to help reinforce the rest o f the struc­ture. After the hull bottom and bilge panels are wired, p lace sp readers o r bulkheads inside the hull to push the p ro p e r beam shape into the upper edge of the bilge pan­els. T hen lam inate a sheer clamp into place with half its width extending above the top o f the bilge panel. P lane o ff the excess wood to pick up the new angle of the upper side panel, o r wale, and attach the wale by screwing th rough its bottom edge into the clam p. Unless it is so small as to allow ro lling over by one o r two persons, your hull will n eed the struc tu ra l stiffness and reinforcem ent o f the sheer clamps to avoid straining things when you roll it over.

Figure 13-16A. Exterior gunwale/clamp for a small, decked boat.

Figure 13-16B. Lichen-type exterior gunwale/clamp and guard.

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Figure 13-17B. Finished interior clamp with toerail and guard.

Figure 13-18. Plane o ff the angle o f top o f inter­mediate clamp before attaching upper wale.

FLOOR TIMBERS

[ prefer good, stout floor timbers built o f a du rab le and stable wood— H onduras m ahogany is best, b u t fir and yellow cedar are also good. Choose a wood that seals well with epoxy. (The bilge is going to have water in it som e tim e o r another, and your only recourse is to seal the holy heck out o f it!)

Because o f th e odd shapes and the expense of the dimensional wood, I usually use tem plates m ade from th in scrap ply­wood to cu t the floor tim ber stock. Templates speed up the work and save on materials.

Pick a starting place, usually nex t to the aft cabin bulkhead. Your plans should

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Figure 13-19. Laying out floor timbers using a level, marking along station layouts on the hull bottom.

state the dep th o f the floor tim ber at that po in t. If they d o n ’t, m easure from the plans with an architectural scale rule. After m ark ing the ap p ro p ria te h e ig h t on the bulkhead, use a small spirit level to m ark a horizon ta l line on the b u lkhead parallel with the athwartships waterline. Your floor tim bers will probably have some uniform cen terline-to-centerline spacing, m ost likely 16 to 24 inches on cen te r o r what­ever your p lans specify. M ark the center- line for each floor tim ber forw ard o f the

aft bulkhead, and m ark ano ther set o f lay­o u t points bo th po rt and starboard where each floor tim ber will lie. W ith a pencil, connect the layout marks.

Go back to your orig inal horizontal m arking along the aft cabin bulkhead and tack a small horizontal cleat on th a t line. With a long batten extension hold one end o f the level on the cleat and m ark an inter­section with the edges o f the floor tim ber layouts. Keep an eye on the level’s bubble to pick o ff the ends o f the floor timbers.

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Cut several small battens th e same width as the floor timbers and place them across the hull at the marks. M easure the depth o f th e “V” at th e keel cen terline , n o ting this d im ension on a scrap o f paper. M easure th e beam s (widths) and no te them on your list. Draw in the floor timber widths and the centerline depths onto your pattern stock and cut out the patterns, and check for an accurate fit in the hull.

T he floor tim ber tem plates may no t fit precisely if you have already taped the seam in the keel o f the boat. To com pensate, set vour p a tte rn in place, level athwartships. With your pencil compass held exactly ver­tical and set at about 'A inch, scribe the out­line o f the true bilge o f the boat onto the pat­tern . R epeat this p rocedure fo r all o f your patterns, and cut ou t along the scribed line. Your patterns will fit in place, b u t will be 'A- m ch sh o rt o f th e tru e height. W hen you transfer th e pa tte rn to your floor tim ber stock, add Z> inch to com pensate fo r the extra height. I usually give these patterns lA- inch or so extra height to allow me to scribe down into perfect position and height.

After cutting out the floor timbers, cut a lim ber ho le in each one so that bilge water will be able to flow through and set­tle at the lowest point in the bilge. I prefer to pu t the limber holes to one side because m ost designs have keel bolts going th rough the cen te rlin e o f the floor tim­bers. Cut the limber holes large enough to accom m odate any anticipated bilge pum p hoses and o ther plum bing that m ight run through the bilge.

Preseal the floor timbers with at least two coats o f epoxy. W hen you install the timbers, bo n d them in place with /4-inch- deep wood flour fillets backed up with #14 x 1/4-inch screws from outside th e hull. I often roll an o th e r coat o f epoxy over the whole bilge area— floor tim bers, panels and all— after installation, ju s t to ensure adequate protection from moisture.

For large boats with a lot o f potential keel strain, I often sandwich dim ensional floor tim ber stock between /4-inch m arine plywood. T h en 1 bond in these floor tim ­bers with epoxy and glass seams to in te ­grate them into the hull structure.

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F i l l e t i n g a n d G l a s s i n g

P l y w o o d j o i n t s

Fillets (coved epoxy paste m ixed with fillers) and fiberglass tape re in fo rcem en t are what make stitch-and-glue construction possible. N ot only do epoxied jo in ts weld the plywood panels together, bu t they effec­

tively transfer structural loads from one sur­face to ano ther to help avoid stress concen­tra tions— and this is truly the essence of what makes a sturdy, well-constructed stitch- and-glue boat such a strong and fine vessel.

Figure 14-1 This wood flour/epoxy filleting mixture has the right consis­tency to work well. Note the paddle-type stir stick used to spread the mix­ture into the joint.

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A fter the plywood panels have been stitched o r fastened in to position, the jo in ts and their adjacent surfaces must be coated first with unthickened epoxy. Coat the ad jo in ing surfaces w ider than your final seam w idth so th a t no p o in t o f the fillet-joint area will be epoxy-starved. For extra-strong, heavy-duty jo in ts you can also distress the jo in t areas with a rough cross­grain grinding with a stiff phenolic grind­ing pad and a 36-grit paper. This cuts into the plywood veneers enough to give more effective keying across the join) area.

Once the jo in t areas have been coated, m ix som e wood flo u r an d Cabosil in to epoxy to create the filleting material. I use a mix o f two-thirds wood flour to one-third Cabosil. The m ixture should be thick: nei­ther syrupy no r too stiff to work. To test for the p ro p e r consistency, h o ld the stirring stick vertically with a golfball-sized glob on the en d o f it; if any p a rt o f the m ixture slides, it is still too th in . W hen the wood flour is too stiff, the m ixture will appear a b it dry an d will result in fillets pep p e red with hard-to-remove air holes. We are look­

Figure 14-2. This wood flour/epoxy mixture is almost too dry to apply prop­erly. Note the holes left in thefillet after being/squeegeed into the joint; they could lead to air holes in the laminated composite jo in t and compromise the strength o f the joint. A bit more mixed epoxy added to the wood flom\would correct the dryness.

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ing for the consistency o f a moderately stiff peanut butter.

Apply the th ickened m ix tu re to the jo in ts using a plastic fillet squeegee custom -cut to shape on the jo b , sm ooth ­ing over the lumps o f filleting mixture. An alternative is to m ake a cone o u t o f bu tcher paper, squeeze an even bead of fil­let m aterial into place, then squeegee the bead into a smooth, even, covedjoint. This process is tidier bu t m ore time-consuming. E ither way, you’ll want to get the fillet mix­tu re neatly in to the jo in t and sm oothed o u t to give the boat smooth, even joints.

T he d ep th o f th e hull fillets should equal the thickness o f the thickest piece of plywood being fastened, and should extend outward from the centerline o f the jo in t 1 'A to 2 times its thickness. D epending on the angle o f the jo in t, the fillet m ight be wider. We want a sm ooth, curved transition from one panel to the next (see Figure 10-11).

With the fillets sculpted into shape, the n ex t step is to apply the glass tape re in ­forcem ents. I t is very im p o rtan t th a t the

Figure 14-3. One method for overlapping fiber­glass tape layers. . . .

lam inate he bu ilt up with the narrow er cloth tapes placed over the fillets first, fol­lowed by increm entally w ider layers. This allows the strength o f the jo in t to gradually transit to the plywood panels— these taperedjoints are m uch stronger and result in hull jo ints and seams that when stressed show a strength similar to the plywood pan­els they are bonding together.

P recu t all o f the runs o f glass tape, carefully folding o r draping each near the spo t w here it will be used. If your design uses multiple layers o f glass tape, p recut all the layers and arrange them into sets. Use m asking tape to identify each set and its location. The more organized you are, the m ore professional the jo b will be in the end. Remember, once you mix epoxy you will have to work h ard and fast; in terru p ­tions due to lack o f p repara tion will only cost you m oney in lost epoxy, and will make a stickyjob that m uch less enjoyable.

Work symmetrically in the boat when glassing the seams. For instance, tape the entire keel-and-stem jo in t in a small dinghy

Figure 14-4. . . . and an alternative method with tapes o f the same widths.

F i l l e t i n g a n d G l a s s i n g P l y w o o d J o i n t s

before starting on the chines. W hen you glass the chines, allow enough time, and have die materials ready, to do both chines in one session. I t ’s easier if you keep your raw epoxy m aterials close a t h and ; you’ll waste a lot o f time and energy if you have to climb in an d o u t o f a large boat each time you need to mix a new batch of epoxy, and moving in and out of the hull also risks shifting the boat out o f alignm ent during the critical bonding process.

I rem em ber a small duck hunting boat we once built. After the hull seams were glassed, som ething about die boat seemed odd and out o f place to me, though I couldn’t immediately p u t my finger on it. A couple o f days later, we discovered that the boat was % inch ou t o f square— it was twisted. T hat boat could never be fixed; no m atter how many tries we made, the epoxy seams had perm anen tly locked the twist into the boat. To this day, tha t boat is up in the rafters o f my shop, a total waste of time and money. Moral: Check and dou- ble-check the squareness o f your boat before you glass the seams. Measure care­fully from stem to b o th transom corners to check for squareness and lack o f twist.

A nother trick to help stabilize the boat and stiffen it before a major glassing session is to tab all the seams with small fillets, essentially serving the same function as small weld tabs on a metalworking project. I tab the n ight before, at the least, so the epoxy fillets cure before I s tart go ing in and ou t o f the boat a lot. You can run your regu lar fillet righ t over the tops o f these tabs without a lot o f bother.

I always fillet and glass the seams o f my boats in one con tinuous session, w ithout allowing the fillet o r the individual layers of glass tape to cure. This obviates the need fo r sanding betw een layers to achieve a

good secondary bond , and it is the m ost efficient way to build . Lay th e fiberglass tape over the fillet joint and lightly smooth it into place with your gloved hand. Keep a sharp eye ou t fo r a ir bubbles, as they weaken the lam inate. C onsider getting a small, too thed fiberglass tooling ro ller to sm ooth ou t bubbles. Press the cloth in place, taking care no t to den t excessively or shift the underly ing soft fillet m aterial. Brush additional un th ickened epoxy over the fiberglass tape to com plete the satura­tion. W hen the c lo th is sufficiently satu­rated, its appearance will change from dry, silver-white to translucent. A ir bubbles should be rolled or squeegeed ou t before

Figure 14-5. Close-up o f epoxy tabs in place on hull joints, here a transom/bottom panel joint, before wire stitches have been removed, and before the major hull glassing o f the interior seams.

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Figure 14-6. A toothed roller aids in smoothing out the glass taping on interior hull joints and helps get rid of air bubbles.

Figure 14-7. A glassing box can make tajring the interior seams a much easier job. I t’s imper­ative that all layers o f this laminate be thor­oughly wetted out before applying it to a seam.

the next layer of tape is applied. Repeat the process for each layer of fiberglass tape. Try to avoid applying add itional epoxy as an overcoat to the final layer; it usually absorbs the excess epoxy from previous layers, cre­ating a better resin-to-cloth ratio. After sev­eral m inutes, if it is obvious that there are going to be some dry spots that won’t satu­rate properly, carefully brush a bit of epoxy as needed to com plete the saturation.

For first-class results that require much less sanding fo r a sm ooth seam, apply a layer o f peel ply on top o f your taped seams. Peel ply, a finely woven polyester cloth, is available from your epoxy o r glass cloth supplier, an d epoxy w on’t ad h e re well to it. Just press a strip of it down into the fresh jo in t, an d allow the u n cu red epoxy of th e jo in t to soak in to it. Use a plastic squeegee to smooth the strip over the layers

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of wet-out fiberglass tape, thus sm oothing o u t and rem oving excess epoxy from the lam inate. After the epoxy has cured , you simply peel o ff the strip, leaving a sm ooth jo in t surface. Peel ply is a w onderfu l time saver, alm ost com pletely elim inating the need to sand the surface once it is removed. Polyester dress lining, available from any fabric store, can work as a substitute for peel ply, bu t your best bet is to buy the real stuff.

Some small fillets th a t are n o t struc­tural hull jo in ts will no t require fiberglass tape overlays. For these jo in ts , m ix the same wood flou r fillet m ateria l and use the rounded end o f a tongue depressor to cove the fillet surface. Let the fillet cure un til it reaches the consistency o f stiff modeling clay. At this point, use a piece of tightly woven co tton clo th— soaked in e ither lacquer th in n e r o r isopropyl alco-

F i l l e t i n g a n d C l a s s i n g P l y w o o d J o i n t s

Figure 14-8B. A length of epoxy-saturated laminate ready to be placed on a seam. Note the worker’s Tyvek suit and canister respirator. She should be wearing eye protection .

Figure 14-8A. A glassing box allows the boat- builder to make fin a l adjustments in the length of the seam laminates for more accurate fits.

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Figure 14-9. After the laminate has cured, the top (peel ply) layer can be pulled o ff and removed. Peel ply results in a much smoother laminate and shortens the sanding time.

hoi—over the fingertip o f a solvent-proof glove to smooth the surface. If you avoid d en tin g o r moving th e sem istiff fillet m aterial, the surface will becom e so sm ooth th a t there will be little n eed for sanding later. In the case o f a brightly fin­ished (clear) surface, the cured , wood- colored fillets will b lend with the natural wood color o f the plywood panel.

A nother way to save time and frustra­tion w hen glassing jo in ts is to make up a glassing box, w hich consists simply o f a base o f scrap plywood ab o u t 14 inches wide and abou t 6 to 8 feet long, to which are affixed sides an d ends abou t 1 inch high. If you carefully m easure and p recut your fiberglass clo th strips fo r the jo in ts , you can do a full wet layup o f a glass jo in t away from the boat. In o u r shop, one worker mixes epoxy resin and fillet mater-

Figure 14-10. Wood flour fillets at the edges of the joints offitted members will make joints stronger and more professional looking

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F i l l e t i n g a n d C l a s s i n g P l y w o o d J o i n t s

ial while an o th e r does cloth layups in the glass box an d a th ird works in the hull under construction applying the fillets and the cloth strips.

T he sequence goes like this: T he per­son in the boat coats the plywood around the jo in ts with u n th ick en ed epoxy p ro ­vided by the person doing the mixing; he o r she then is handed some freshly mixed filleting com pound with which to cove the joints. Meanwhile the worker at the glass­ing box is laying u p the fiberglass cloth portions o f the hull seams in reverse order o f application: first a wide layer o f peel ply, th en the widest layer o f fiberglass cloth tape, then the nex t narrower, and finally

the narrowest, saturating all the layers with epoxy resin. W hen all the air bubbles have been ro lled o r squeegeed out, the whole laminate is lifted ou t o f the box and handed to the worker in the boat, who lays it over the fresh fillet m aterial and rolls o r squeegees ou t the last rem aining air bubbles.

Working this way divides the labor into manageable chunks and minimizes confu­sion an d mess. Try it with a coup le o f friends; your glassing day will go by quicker an d m ore enjoyably. D o n ’t fo rget ap p ro ­priate refreshm ents at the end o f the day to celebrate the com pletion o f some good, hard work.

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O nce th e m ajor in te rio r hull jo in ts and bulkheads are glassed, the sheer reinforce­m en t or clamps are in place, and the floor tim bers installed, the hull m ust be ro lled upside down to com plete th e ex te rio r work. I t’s im portant that the in terior struc­tu re is a t a po in t w here the hull can with­stand the strains o f rollover w ithout dam ­age. R em em ber though , th a t too m uch in te rio r work will add w eight and can m ake the rollover m ore difficult, increas­ing the chances o f damage.

If you’re working on a tight budget, a boom crane o r o ther expensive machinery to assist the rollover is probably ou t o f the question . You’ll n eed to roll the hull the old-fashioned way: with m anpower. How m any willing helpers will it take? H ere’s a sim ple form ula: Take the leng th o f the boat, subtract 8, divide the rem ainder by 3, and ro u n d u p to the nearest whole num ­b e r fo r th e optim al req u ired m anpower. For exam ple, if your boat is 22 feet long: (22—8 )/ 3 = 4.75. You’ll n eed at least five people total to help you in the rollover. If you have m echanical aids such asjacks and stands, you m ight get by with fewer people. But there is ano ther rule to keep in mind:

Your rolling party will take as m uch m an­pow er as you have available. If you have five p eop le you’ll th in k you had ju s t enough—if you have eight you’ll think you could never have done the jo b with fewer.

You have two basic m ethods of rolling the b o a t over. You can roll as is w ithout jigs o r ro ller fram es o r you can fabricate a simple wooden rolling fram e with which to hold the boat and cushion the rolling process. I have rolled boats up to 36 feet long w ithout any jigs with little problem . But it is a bit easier on the nerves to have a ro lling fram e. It d o esn ’t cost m uch m ore to build and can m ake for a m uch easier time.

Obviously, the area fo r the rollover m ust be clear o f c lu tte r an d ju n k . Have sawhorses, jacks, and blocks ready. I keep som e o ld tires, m attresses, cushions, and rolls o f ca rp e t handy to cushion the hull a t its contact points with the floor during rollover.

M ake sure th a t one person has been designated as the leader, and talk the rolling process th ro u g h before you start. Who will do what, and in what sequence? You want to avoid finding yourself with sev-

R o l l i n g O v e r t h e H u l l

Figure 15-1. A shof)-made rollover jig can take a lot o f stress out o f the rollover process for a larger stitch-and glue boat.

Figure 15-2A. Small and medium-sized boats can be rolled over with good guidance and the help o f a lot o f friends with strong backs. This 22-foot Surf Scoter powerboat will take the better part o f an hour to roll over.

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D e v l i n ’ s B o a t b u i l d i n g

Figure 15-2B. Rolling the hull in stages, with breaks wherever you can block the hull and not worry about it falling.

Figure 15-2C. Once the hull is rightside up, it ’s fairly easy to hold upright until blocking or shoring can be put into place.

era] thousand pounds o f weight and thou­sands o f dollars o f hu ll midway th rough the rollover, with conflicting opinions on what to do next!

D uring the lifting process, block the hull in to position at intervals, and con­stantly check to make sure that no person is han d lin g too m uch weight. W hen the gunwale is h igh in the air, with the hu ll’s weight ready to pass the balance poin t and shift to the o th er side, move two o r m ore people to the o ther side to catch and slow the hull as it rolls over. With the hull fully on its side, transfer people around to lower an d block th e hu ll in intervals, un til the hull is in the full inverted position.

My shop is wood-framed, and the walls and ceiling canno t support the strains of

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tackles to lift o r lower the hull. But I do occasionally use a block and tackle off the side walls to act as a safety brake, control­ling the speed o f rollover and assisting the rollover crew. W ith a 4:1 tackle an d a scared, s trong operator, the hu ll can be slowed down an d safety assured; come- alongs work well for this also.

If your m anpower stabilizes the hull at stem and stern, lifts and lowers in intervals, blocking for safety as you go, and constantly m onitors w here the weight is shifting, the rollover should go smoothly and safely, and a lot easier than you m ight suspect. But for

hulls bigger than 35 feet you will definitely want a boom crane. For a couple o f h u n ­dred dollars you can safely flip your labor of love and save a lot o f grief.

The use o f rollingjigs aids the rollover process b u t never entirely elim inates the basic jo b o f lifting o r jack in g u p the hull to the balance p o in t then safely lowering it down on the o ther side. But if you think the process th rough and make sure you or your designated rolling leader has the last word and th a t all helpers know this, your rollover will go through without a hitch.

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Wire stitches can n o t be left in the hull because th e norm al hea ting and cooling cycles o f the b o a t may cause the wires to migrate to the surface, m arring the finish. I feel so strongly about this that at times we count the pulled wires to make sure every suture comes out.

In a small boat you can place runs o f fillet m aterial between the sutures, allow these to cure, th en pull o u t the wires before glassing the jo in ts inside and out. But in larger boats, where the hull is going to be walked in and the strains are greater, it may be better to complete all the interior hull seams with the full epoxy/fiberglass cloth composite jo in t, allow to cure, then rem ove the stitches. If you are an experi­enced builder and have full confidence in your hull, go ahead an d tab your seams and pull ou t all stitches early before glass­ing in te rio r seams. But i t ’s n o t that big a deal to pull o u t stitches after the glassing has been done.

T he wires used to stitch the panels together are only left in place until the fil­le ted , tap ed seams have fully cured. Applying h ea t to the wires softens the cured epoxy enough to allow the stitches

to be pulled with a pair o f pliers. Some bu ilders p re fe r to use a fast epoxy and rem ove th e wires im mediately, while the epoxy is still setting, b u t I like to wait overnight and remove the wires when the epoxy is m ore fully cured.

If you have cured epoxy seams over the wires, begin by untwisting the wire suture two o r three turns, then clip the wire ends nex t to the twist so bo th ends can be easily grabbed with pliers. Apply heat, and when the end o f the wire is glowing red-hot, allow a m inu te o r so fo r the hea t to transfer th roughout the wire. Using your pliers, pull the wire toward you with a levering motion against a scrap wood block. The wire should ease ou t nicely. If the wire breaks inside the suture, simply hea t the o th er end and pull that out.

There are two methods o f heating the stitches. T he first is to use a small h an d ­held propane torch, bu t in addition to the obvious fire hazard o f using an open flame in your w orkshop, you m ust be sure to hold the torch par allel to the hull surface to avoid scorching the plywood.

In my shop, the preferred m ethod uti­lizes a 12-volt battery and a set o f ju m p e r

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cables. C onnect a ju m p e r cable from the negative post o f the battery to one o f the wire ends, then connect a second ju m p e r cable between the positive post and the car­bon rod elem ent from the center o f a D-cell flashlight battery. (You will need to dissect a used battery to expose the post.) H old the positive-post rod e lem en t briefly to the su ture wire until it glows (the carbon rod helps eliminate the potential o f arc welding the w ire). Be careful no t to connect the cir­cuit too long, since it generates a lot o f heat quickly. If you apply too m uch electricity the epoxy will flam e o r possibly b u rn the plywood panel. E xperim ent, an d you will soon find how little contact time is needed to adequately heat the wires.

If I ’m n o t using the battery m ethod , I usually h ea t one o r two wires ahead o f myself and then re tu rn to the wires to pull them once the hea t has transferred th roughout the wire. Never leave pieces of wire in the hull. Dig the pieces out and fill in the hole with filleting material if need be.

Figure 16-1. A battery jig will heat the wire stitches to allow their removal from the hull.I t ’s very important to remove the wires— they could work their way out o f the jo in t over time.

D o n ’t ju s t p lug the tops o f the holes with filler; fill them with resin, which is fairly easy to do during the exterior sheath­ing process. (We’ll discuss that later.)

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S t i t c h -a n d -Gl u e H u l l

Larger stitch-and-glue boats might require a final skin thickness th a t limits the flexi­bility o f the panels. A boat larger than 30 feet will require skins of X- to 1-inch thick­ness, but plywood that thick is hard to find and extremely difficult (read, impossible) to ben d into shape. T he solution is to use thinner, more flexible plywood for the ini­tial stitch-up p rocedure to shape the hull. T hen , once the in terio r jo in ts are filleted and taped, some in terior structure assem­bled, and the hull rolled over, layers o f thin plywood can be lam inated on to the hull exterior to build it up to the desired final thickness. I call this process “plywood cold m old ing ,” an d have used it on hulls as sh o rt as 18 feet to achieve the co rrec t shape an d skin thickness, an d as long as 48 feet to give them strength to stand up to their in tended service duty.

This m e th o d o f cold m old ing is easy and fast because you are using the initial stitch-and-glue hu ll as an in tegra l mold, an d it allows th e stitch-and-glue b u ild er access to larger boats that wouldn’t be pos­sible with single-layer skins.

If you have studied cold m olding as it applies to round-b o tto m ed boats, you

lea rn ed to spile (shape) the planks to ensure full contact with the hull’s surface. In stitch-and-glue construction, however, the hull is m ade entirely of developed ply­wood panels, so you can avoid spiling com­pletely. T he only shaping you need to do is rough-cutting your panels to easily place them on the boat.

I d o n ’t scarf the panels (or jo in end to en d in a con tinuous sheet) when cold m olding, and d o n ’t a ttem pt to cold m old add itional hu ll layers with any plywood thicker th a n '% inch. The real cold-molding w orkhorse fo r m e is J4-inch plywood app lied in single layers un til the desired hull thickness is reached.

W hen you know that your hull will require cold m olding to build up its final skin thickness, a good trick is to cut ou t the cold m olded layers when you loft and cut the initial hull panels. Typically, I loft ou t my hull panels on my scarfed plywood sheets, then before cutting them I use the lofted patterns to lay out as many o f the th in n e r cold-m olding plywood panels as I ’ll need for the final laminate. While the initial stitch-and-glue panels n eed to be scarfed full length , these cold-m olding

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Figure 17-1. A 29-foot Means o f Grace hull ready for the reinforcement provided by cold molding additional plywood layers.

layers can be simply butt jo ined— though its im portan t to stagger th e b u tt jo in ts if several layers are to be applied . W ith this layering m ethod it is quite simple to cut out the whole stack at one time, saving a lot o f effort when th e cold m old ing process begins.

T he cold m old ing p ro ced u re is sim­ple. Make sure you are well p rep ared , because once th e epoxy is m ixed it will begin setting up, and you m ust work fast. Take your p recu t panels fo r the first layer and place them in rough position on the boat. Staples o r screws help hold the sheets in position un til you have dry fitted the en tire layer. M ark th e position o f each sheet carefully fo r its fit on the hull, indi­cating which face is up. After all the pan ­

els have been fitted, remove the num bered sheets from the hull.

Next, drill 14- to Xe-inch diam eter holes abou t 6 to 8 inches on center th roughout all th e panels. These small holes he lp to prevent air en trapm ent between the layers. You can stack-drill these holes to help speed up the p rep a ra tio n process. Im probable though it seems, it is very com­m on w hen you fasten a sheet o f plywood around its perim eter, w hether cold m old­ing hull layers o r laminating a deck, to trap large bubbles o f air betw een the layers. T he small holes allow air to escape, and you will know you have good contact betw een layers when you see a small am o u n t o f epoxy resin ooze o u t o f each hole. T he epoxy oozes will also act like

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nails to help bond the two layers together.Mix the epoxy without thickeners and

roll a generous am oun t o n the face-down sides o f the panels to be cold molded. Set these aside while rolling an equally gener­ous coat o n the hull o f the boat. If you notice gouges o r holes in the hull o r the panels, fill them with th ickened epoxy. Make sure every surface an d edge o f the hull and the cold-m olding stock is coated with epoxy before positioning and fasten­ing the plywood to the hull.

I usually use pneum atic , air-powered staplers with stainless steel o r M onel bronze wire staples in a variety o f sizes and lengths to fasten the layers to the hull. If you d o n ’t own a pow er stapler, consider

ren ting one. H an d staplers, bronze ring- shank boat nails, and small screws will also work. Place a fastener at least every 4 to 6 inches to guaran tee con tact between pieces until th e epoxy cures. You should have a good ooze o u t o f the small holes; trapped air produces a hollow sound when you ru n your hand over the panels, and it’s a good idea to check out the whole surface to make sure no air is trapped.

Some designs have so m uch shape in portions o f the boat th a t even 14-inch ply­wood in large sheets w on’t take the bend easily. In these cases, cut 4-inch-wide strips from the %-inch plywood an d apply these diagonally to the hull ju s t as you would the larger sheets. Make sure that you coat the

Figure 17-2. Cold molding the bottom bow sections o f this 29-foot Black Crown powerboat is best accomplished by using smaller 4- to 6-inch-wide strips o f plywood applied diagonally. Note the use o f epoxy and fillers in gaps to eliminate any air voids or entrapment.

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strips with epoxy. D o n ’t spare the fasten­ers, and work fast and organized.

After the epoxy has cured, prepare the final exterior surface for fiberglass sheath­ing. Pull the m echanical fasteners within 4 inches o f the chines, stem, keel, and o ther edges since those areas m ust be rad iused before fiberglass can be applied , and the edge tools used for the rad iusing would quickly dull if they came into contact with fasteners. Also check for fasteners standing proud o f the surface; either set (drive below the surface) o r pull these. I use a large screwdriver and m allet to set staples. G rinding fasteners off is an invitation to trouble, since the bu ried rem nants could

eventually m igrate th rough the fiberglass ju s t as wire stitches will if n o t pulled . It would be best in a perfect world to pull out all fasteners, but that rarely is possible.

Cold m old as m any layers o f th in ply­wood on to the hull as n eed ed to attain designed thickness— even m ore if desir­able to com pensate for rough usage such as ice o r deadheads o r prolonged dry stor­age on a trailer. Additional layers in a local­ized area o f the hull o r deck may be nec­essary to dissipate such stresses and strains as a s ide-m ounted winch for oceano ­graphic work o r commercial fishing. A lit­tle ex tra p ro tec tio n is p re tty easy to add now, but a lot h arder later on.

L26

Ke e l s , R u d d e r s , S k e g s ,

a n d O t h e r Ap p e n d a g e s

Rudders, centerboards, skegs, keels, stem bands, and o th e r appendages can be p re ­built from dim ensional wood o r lam inated plywood stock. Since keels an d skegs are po ten tially h igh wear o r heavily loaded structures, take great care in securing them to the hull and protecting them from mois­tu re penetration . I use bolts and screws in addition to b ed d in g th em in epoxy to assure p roper attachm ent, and also use ade­quate filleting an d glass tape re in fo rce ­m ents to keep the appendage from being wrenched ou t o f position if stressed. O n the bottom o r outerm ost surface o f a keel and stem band, I p re fe r to use ironbark— a du rab le hardw ood—as a shoe fo r a m ore durable, replaceable chafing surface. But a lot o f people prefer a stainless steel o r brass half oval band to help with chafing. Either m e th o d works fine an d is a worthwhile addition to the boat.

S heathe the in te r io r o f the center- board o r daggerboard trunk with the same considerations as the exterior o f the hull. A nd it’s im p o rtan t th a t all plywood sur­faces be fully sealed before the sheathing is applied, since these areas would be almost impossible to service later. A nother alter­

native in the inside o f a centerboard case is to forgo fiberglass sheathing. I sometimes p ro tec t the in te r io r surfaces with a layer o f Xe-inch countertop laminate glued with epoxy resin to th e plywood, thus provid­ing a slick and durable shield against the b o a rd ’s fric tion an d load ing pressures. This elim inates th e n eed fo r additional fiberglass sheathing and makes for quite a durable installation.

W hen using the countertop laminate, stop a coup le o f inches from th e bottom o f the trunk , leaving a sufficient landing fo r the h u ll’s clo th sh ea th ing to wrap around the edges. This also facilitates fair­ing. Glue the laminate in place with epoxy before assembling the case.

Assemble the case or trunk as a stand­alone structure and insert it so as to p ro ­tru d e several inches beyond the hull sur­face, using heavy fillets an d glass cloth laminates to secure it inside the hull. After these fillets have cured , trim the excess flush with the hull. When you later sheathe the exterior (Chapter 19), overlap a t least YA inches o f cloth up in to the in terio r o f the case or trunk. The edge o f the dagger­b o ard case o r cen te rb o a rd tru n k is

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K e e l s , R i ' D D e r s , S k e c s , a n d O t h e r A p p e n d a g e s

Figure 18-1. Typical 30-fool hull bottom/keel stitch-and-glue joint.

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extremely vulnerable, and it’s im portant to use enough cloth to strengthen this area of the hull.

All these structures must be carefully sheathed in fiberglass cloth and epoxy (see C hapter 19), and w hether it’s best to apply them before o r afte r your ex te rio r hull sh ea th ing will vary with the particu lar design you are bu ild ing and with your bu ild ing schedule. C erta in appendages such as a cen terboard tru n k o r a dagger- board trunk are best built up and installed in the boat before the h u ll’s ex terio r sheathing. But the exterior stem and keel on a boat like Surf Scoter are best applied afte r the ex te rio r hull sh ea th ing is com ­pleted and then glassed in place separately.

Figure 18-4. Daggerboard trunk details.

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S h e a t h i n g t h e E x t e r i o r

A durab le o u te r skin o f fiberglass cloth set in epoxy adds a great deal o f strength and abrasion resistance to a stitch-and- glue boat. U nsheathed an d exposed ply­wood is m uch m ore vulnerable to abra ­sion or impact damage, which could lead to m oisture pene tra tion . Sheath ing also assures a tiiick, consisten t epoxy m atrix over the en tire surface o f the structure , and spreads th e stresses o f use over its tough coat. Moreover, the m aintenance of boats sh ea th ed with clo th an d epoxy is greatly reduced , com ing m uch closer to that theoretical ideal, the fiberglass boat. I use e ither 4- o r 6- o r 8-ounce fiberglass cloth, depending on the in tended service. T he 4-ounce cloth will resu lt in a sm oother final surface since the th icker yarn bundles o f the 6-ounce o r 8-ounce cloth tend to print-through (show a cloth pattern in the final pain ted surface over tim e), so I use th e 4-ounce clo th on yachts that are to be finished with a dark paint. For workboats an d o th e r craft anticipating rougher duty, or boats to be p a in ted a cooler, ligh te r color, 6- o r 8- ounce cloth works best.

T he cloth can be applied e ith e r wet

o r dry. T he wet m ethod calls for coating the hull with epoxy before laying the cloth. In th e dry m ethod , th e clo th is d raped over the hull surface, then epoxy is app lied to the cloth. I p re fe r th e dry m ethod because the cloth is m uch easier to manage, and it makes a sticky jo b m uch m ore manageable.

T h ere are o th e r cloths th a t can be used for sheathing, mainly Dynel, X ynole/ polyester, Kevlar, or polypropylene. While I have no particu la r g ripe with using any o f these cloths, I have no evidence th a t would p ro m p t m e to switch from glass cloth. T h e synthetics can be quite a bit h a rd e r to han d le an d work with than glass cloth, they are expensive, and your sources o f supply are m uch m ore limited.

Application techniques for glass and synthetics can be approached in approxi­mately the same manner. Synthetic cloths such as Dynel and Xynole/polyester come in lightw eight 4-ounce an d 4.3 ounce weights, respectively, but they ten d to bulk u p to the equivalen t thickness o f approxim ately 8-ounce glass cloth when wetted out with epoxy.

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A P P L Y I N G C L O T H W I T H T H E I ) R Y M E T H O D

First, with 80-grit san d p ap er sand the w ooden hull surfaces to be shea thed to provide a m echanical tooth for the epoxy. I p refer the wider 50-inch fiberglass cloth to 38-inch cloth because it m ore easily cov­ers the panels. Precut to length the pieces (panels) o f cloth so you w on’t have to make cuts later with sticky hands. And it’s a good idea to add about 10 p ercen t to the length to allow working room . W hen lay­ing out the cloth sections, try to keep the topsides sheathing jo in ts low o r below the waterline. Make sure all hu ll edges have been fa ired an d sm oo thed o r ro u n d e d over, so the cloth will lie sm ooth and flat over the plywood.

C oat all exposed plywood edges with unthickened epoxy, thoroughly saturating the edges to seal them completely with sev­eral coats. A lthough this can be done ju s t p rio r to d rap ing the cloth panels on the hull, i t’ s easier if you coat the edges a day o r two earlie r an d lightly sand the cured epoxy before finally positioning the cloth for sheathing.

I t’s easiest to work with a partner when sheath ing . W ith your partner, grab each en d o f the c lo th panel, pulling gently to keep it off the floor an d suspended ju s t over the hull. Now d ro p the dry cloth in position, sm oothing out wrinkles with your hands; you’ll see it has a natural tendency to sm ooth out. T h en mix and p o u r small quan tities o f u n th ick en ed epoxy on the upperm ost parts o f the cloth panel. With a plastic squeegee, move the epoxy until it uniform ly satura tes the cloth, using a figure-eight m otion to h o ld the resin on

Figure 19-1. Glass cloth sheathing laid out on the. cabin top o f a 29-foot Black Crown power­boat. This step allows the boatbuilder to trim accurately and keep the job as neat as possible.

the cloth. Begin in the m iddle of the piece and work toward the bow and stern; that way the m inor stretch o f the fiberglass panel has somewhere to go. Leave at least a 4-inch overlap on each o f the cloth pan­els, wetting out only one panel at a time. I overlap a t the chines, stems, and transom edges, m aking sure a t least two layers of cloth are on every jo in t o r seam to ensure extra strength.

If your pieces do not overlap on the chines and o ther joints, use an additional layer o f cut fiberglass cloth tape there. In boats expecting rugged service, you might w ant th ree layers o f cloth over all jo in ts. Again, try to keep the mass o f the overlaps below the w aterline to m inim ize the am ount o f fairing you’ll have to do on the visible portions o f the hull; you w on’t always succeed, b u t try anyway.

M ake sure th a t all o f the fabric has been completely saturated with epoxy, bu t

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Figure 19-2. Trimmed and smoothed, the cloth is ivetted out. M ix up large buckets of epoxy, pour over the glass, and with a squeegee, use a figure- eight motion to saturate the cloth and the plywood below. Note the Tyvek gauntlets to protect the worker’s forearms.

d o n ’t leave too m uch epoxy on the cloth, because the cloth can have a tendency to float a round . A fter satura ting the cloth, squeegee ou t excess epoxy. T he cloth sur­face should have a clear, dull appearance, and the weave o f the cloth will still be quite visible and show a cloth texture. If you wait a couple o f hours you can come back and roll an o th e r layer o f u n th ick en ed epoxy over the now-sheathed hull. But if you have to wait overnight, sand lightly before recoating.

After th e epoxy has cured , use a grinder with an 8-inch pad and 80-grit discs to lightly sand the rough edges o f the cloth overlaps. H and-sand the true edges o f the

chines and o ther edges to avoid cutting into o r damaging the cloth. Fair and smooth the surface in preparation for a second coating o f un th ickened epoxy, which m ust be ro lled on evenly. This coat should com ­pletely fill the weave o f the cloth; if not, a th ird coat should be applied , wet on wet over the second coal. If you have waited overn ight o r lo n g er befo re applying the second coat to the sheathing, wash the area with clean water then dry it off. Your sand­paper will no t gum up quite as fast and you will avoid con tam inating the epoxy and glass cloth surface.

To avoid a rough, dim pled epoxy sur­face (roller stipple pa tte rn ), use a heat gun

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Figure 19-3. Overlapping the glass cloth joints provides strength and ensures the integrity o f the hull ’s exterior. The taped-off area of the transom will be finished bright.

to warm the epoxy so it flows o u t and smooths itself. After heating the surface, I often brush the epoxy lightly with one o f

the 4-inch foam throwaway brushes or with a split foam roller to sm ooth the surface.

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S a n d i n g a n d F a i r i n g

Stitch-and-glue boatbu ild ing requires a considerable am oun t o f sanding and fair­ing, a lthough m uch o f the in te rio r hull seams an d bulkhead sand ing can be avoided by using peel ply on the taped composite seams. You m ust take consider­able care to never cu t in to the layers o f fiberglass cloth when you sand; use the sanding surface as a guide: T he ep o x y / cloth lam inate is fairly tran slu cen t and when sanded creates white dust, but when

you sand in to the cloth, the surface will become silvery. Use the color variance as a guide to how deeply you are sanding.

Try to work only one area o f the disc’s surface when using a disc sander. Lift one edge o f the disc slightly to h e lp keep it cool, contro lling the contact a rea to one position in re la tion to the disc. T he g rea te r the fric tion an d heat, the faster the sanding disc will dull. Using light pres­sure also keeps the san d e r from walking

Figure 20-1. Two-handed sanding gives the best control over the sander. When the rear o f the sander is lifted slightly, the sandpaper will throw off dust and run cooler.

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Figure 20-2. The dust collector on the Makita 9207 grinder/polisher makes the nasty job o f san ding much more pleasan t.

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around and getting out o f control. O n the hu ll exterior, never sand corners, tigh t edges, stems, chine o r keel lines, o r tran ­som edges with the disc sander; the epox- ied cloth edges can be quickly sanded th rough , even by the m ost skilled o pera ­tor. Confine the disc sander to open , flat surfaces, sand ing co rners o r jo in ts by hand . M ost work with an 8-inch sander- polisher employs 80-grit discs.

Use epoxy to recoat spots w here the cloth weave has been exposed by sanding. Keep in m ind th a t different epoxy fillers sand with varying degrees o f ease, depend­ing on the density o f the m ixture. W ood flou r is relatively difficult to sand, som e­thing to bear in m ind when you are using that mixture to fill imperfections.

Use m icroballoons m ixed with epoxy for repairs you need to sand ou t smoothly and easily. Use an ep o x y /m icroba lloon m ixture to help even o u t glass cloth over­laps an d any air bubbles th a t show u p in the sheath ing . If no t filled, airholes will cause grief in the final finish.

O ne trick when repairing gouges is to use ce llophane packing tape, som etim es called gator tape, to ho ld the epoxy filler material in the repair area, preventing the m ixture from sagging o u t o f place while curing. T he tape acts as a so rt o f p o o r m an ’s peel ply and m aintains a sm ooth surface th a t requires less final sanding after the patch cures. Sand the repair spot sm ooth and recoat the surface with unthickened epoxy.

After fairing the hull and before paint­ing, apply a final coat o f epoxy. This last step thorough ly an d uniform ly seals the en tire s tructure , provides additional moisture-proofing, and creates a sm ooth, stable base for the paint. Lightly sand this

last coat with 220-grit sandpaper on a ran­dom orbit sander o r a small palm sander.

Many o f these sand ing tools are now available with dust collection systems to aid in removal o f sanding dust. You can stay a lot m ore comfortable and make the sand­ing jo b a lot m ore pleasant if you attem pt to elim inate a lot o f the dust. Fein Power Tools C om pany o f P ittsburgh makes the best state-of-the-art dust rem oval system and tools com patib le with th a t system. If you can afford it, these make fine com pan­ions during those many sanding hours.

Also d o n ’t neglect wearing a respirator, an d by all m eans d o n ’t go skimpy on changing ou t your sandpaper frequently— while dull sandpaper can still cut, it takes a lo t m ore pressure an d is h a rd e r on the sanding tools and the sander than it needs to be. C hanging san d p ap er frequently helps keep you and the jo b efficient.

D on’t forget to wash off the greasy by­products o f the epoxy curing process with clean w ater an d dry the surface before starting your sanding. This cleaning o f the surface will allow your san d p ap er to cu t cleanly and clog u p m uch less than if you had neg lected this step. Simply wipe off with clean water and towel dry with clean shop towels. Washing off the surfaces also helps ensure th a t you d o n ’t contam inate the epoxied surface. (And speaking o f shop towels, check with a local d iaper ser­vice. Most will sell som ewhat ta ttered bu t clean diapers for not too steep a price.)

While most epoxy companies advertise that recoating w ithout sanding is possible u p to 72 hours a fte r the first coal is applied, I feel it’s best to sand between any epoxy coats that have sat m ore th an 24 hours. In most cases I sand even if it’s only been overnight.

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Ma r k i n g t h e Wa t e r l i n e

AND PAINTING THE BOTTOM

M A R K I N G T H E W A T E R L I N E

The smart move is to paint your boat’s bot­tom before tu rn ing the hull rightside up. Before painting, you must locate and mark the waterline, which is m uch easier to do while the hull is still upside-down. Begin by leveling the inverted boat fore-and-aft and athwartships. From your plans, deter­mine the freeboard from the waterline to the top o f the sheer at the stem and at the two transom corners (just as we did origi­nally to true the hull). M easure from the floor (assum ing th a t it’s reasonably flat) up to the stem and add that dimension to the freeboard to determ ine the waterline point. I usually d o n ’t mask to the designed waterline, b u t allow the boat’s antifouling bottom coating to ex tend anything from an inch to a couple o f inches above the designed flo tation w aterline, dep en d in g on th e size o f the boat. This allows for an an tifou ling splash zone and guards against the possibility o f grass growing right at the waterline, and allows for slight

variation in weight o f your finished boat.M easure up from the floor and m ark

the hull stem at that po in t o f intersection, then do same fo r the corners o f the tran ­som. If your shop floor is qu ite level you can m ock up a simple m ark ing j ig with a sawhorse an d som e sticks. Move a ro u n d the inverted hull, m arking as many water­line points as you need.

If your shop floor is n o t level, use a w ater level o r a transit. Clamp a length o f clear hose between the stem and transom corners, with a bight o f hose hanging down betw een those points. Fill the hose with w ater u n til the ends o f the water colum n are at the b o a t’s waterline, then move one end o f the hose along the hull to mark the waterline fore and aft. The m ore marks you make, the easier it will be to mask the line.

T he nex t step is to stretch masking tape along the marks. Pull long stretches o f tape with even pressure, progressing from stem to transom. Keep the tape par­allel to the markings as you apply it. Lightly press the tape in to place; do n o t ru b it firmly until the whole side o f the hull has been masked. W hen you go back to do this, sight along the hull with your eyes at

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M a r k i n g t h e H' a t e r l i n e a n d P a i n t i n g t h e B o t t o m

w aterline height. If the m asking line appears crooked, sight it from as far away as possible to doub le check. If there is a crooked section, do n o t rip off the tape, bu t use it as a reference for a second line o f tape applied over the first.

BOTTOM PAINTING

D epending on where you will use your boat, the best bo ttom coating will be an an tifou ling paint. T h ere are several antifoulants to choose from, including anti­fouling paints and epoxy-copper antifoul­ing coatings. Paints are generally oil-based, a lthough th ere is a tren d toward water- based form ulas to conform to new envi­ronm ental regulations. I have found that you can p a in t any o f these over a sanded epoxy coated bottom (220 grit) with good results. T he p roblem with an tifouling paints is that they m ust be renewed annu ­ally. They are soft and d o n ’t wear well, par­ticularly on a trailered boat th a t is in and ou t o f the water a great deal. Antifouling paints are expensive, too, so there is a sub­stantial investm ent in annua l recoating material and labor costs.

Epoxy-copper antifouling coatings are very expensive, bu t help avoid yearly appli­cation. These coatings are finely g ro u n d copper, co p p e r/n ick e l, o r copper-oxide w ithin an epoxy resin base. They m ust be m ixed with an epoxy system an d can be app lied to the bo ttom with a ro ller o r sprayer The copper is toxic to m arine ani­mal life and wards off m arine p lant growth, so the only yearly m ain tenance is lightly wet-sanding the bo ttom to expose fresh, nonoxidized copper particles. Manufactur­ers recom m end about 20 mils (.02 inch) o f coating thickness to ensure sufficient cov­erage. Since .75 to 1.0 mil will e rode each

year, the life expectancy o f the coating (according to the m anufacturers) is 10 to 15 years. This is optimistic, bu t even if the lifetime is half that, the coating is still eco­nomical. A nother benefit is that if you take the time to carefully sand, smooth, and buff the bottom of the hull after application you can achieve a slick, almost friction-free sur­face, which creates a m uch faster sailboat or m ore efficient pow erboat. I believe these coatings are the closest to being environ ­mentally responsible, and in the long run they can save the boatow nera considerable am o u n t o f money. O n my boats they are becom ing a com m on bottom-coating appli­cation. They can also function as a good base for conventional an tifou ling paints, providing longer-term p ro tec tion for explo ra tions in to areas w here annual haulouts m ight be difficult o r impossible.

Avoid using m arine enam el paint for bottom coatings. Topside enamels are no t designed to withstand constant immersion, an d they blister an d fail rapidly u n d er water. Only for the smallest skiff o r dinghy would I consider applying a topsides paint to underw ater surfaces.

Prepare the faired, sm ooth hull with a final sand ing with 220-grit sandpaper, sanding the corners by hand . Dust the freshly sanded surface and clean areas o f suspected contam ination with water. Apply an tifou ling pa in t directly on the dry, sanded hull, over an epoxy primer. I use a p ro d u c t called Ditzler DP 40, which adheres well to the epoxied hull and pro ­vides a good base for bo ttom paints. (Actually DP 40 works well as a conversion coat for all paints.)

If you use an epoxy-copper antifouling system, roll the coa ting thickly over the freshly sanded hull bo ttom , an d use dis­posable foam brushes to tip it off. It takes

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D e v l i n ’ s B o a t b u i l d i n g

Figure 21-1. Bottom coating in process on a 22-foot Surf Scoter powerboat with inboard diesel engines. The shaft tube has not yet been trimmed. Note the dishes on each side of the stern tube for better water access to the propeller.

a b it o f finesse to get the application both thick and sm ooth, and it may take two or th ree coats to build up the necessary 20- mil thickness. This epoxy an tifou lan t is slow-curing, and may require several days

betw een applications: d o n ’t hurry the process. Between coats, use 220-grit sand­paper to smooth the surface and im part a bit o f tooth for the next coating.

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R i g h t i n g t h e H u l l

W e’ve already rolled the hull once; the p rocedure is fundam entally the same this time around, except that you must be care­ful n o t to dam age the shea th ing o r ex te ­rio r appendages o r m ar th e soon-to-be pain ted topside surfaces. Take ex tra p re ­cautions to pad the floor and clear the area o f anything that m ight damage the hull.

This rollover is always a heady time, m ixing anxiety with enthusiasm . You will experience one o f the finer m om ents o f

boatbuild ing w hen you first see th e true waterline as the hull is positioned rightside up. Take a m o m en t to apprecia te how m uch has been accom plished, an d imag­ine the fin ished boat. Try to keep your rollover slow and well-organized, and d o n ’t le t your en thusiasm get the best o f you. T h ere ’s still a lot o f work ahead, bu t you’ve gone a long way toward breathing life into a pile o f materials.

I

Figure 22-1. This 29-foot Means o f Grace has just been rolled rightside up and is ready for interior finishing and launching.

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I n t e r i o r S t r u c t u r e s

O nce you have savored the exuberance of com pleting the hull, it’s time for a dose o f reality. Climb in to the boat with an arm ­load o f plans, a framing square, tape mea­sure, felt-tipped pen, and a couple of long, stiff battens.

Your hull, now rightside up, should be leveled to the w aterline both fore-and-aft and athwartships. Keep in m ind th a t each step o f the rem aining construction needs to happen in its given order and with sufficient tim e and effort. D on’t be overwhelm ed by the num ber o f projects yet to be completed, and resist m aking a list o f them . Ju s t pick them off o n e by one. G uard against post­ro llover stall-out. W hen 1 was younger, 1 enjoyed long-distance running , which any ru n n e r will tell you involves m ind over mat­ter. S trength and stam ina are secondary to mental resolve, and the key is to stay focused and no t be d istracted by the distance th a t rem ains. F ind your rhythm , keep a steady pace, and go one step at a time.

did n o t do so earlier, before tu rn in g the boat upside down for shea th ing ), a struc­ture that bears the weight o f the mast and w ithstands the com pression loading and strain o f the mast heel. If your design calls for a deck-stepped mast, you’ll need to build a structure from the deck to the keel to d istribu te the com pression loads. Generally, the mast step can be viewed as an ex tension o f the floor tim b er/cab in sole gridwork. I t may be as sim ple as an

M A S T S T E P

If the boat you are bu ild ing is a sailboat, you m ust construc t the m ast step (if you

Figure 23-1. Look at the mast step as an extension o f the floor timber/cabin sole grid- work, though in a larger boat the load must be spread over a greater area.

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I n t e r i o r S t r u c t u r e s

extra longitudinal spanning two floor tim­bers, though in a larger boat, the load m ust be sp read over a g rea ter area. T he com pression forces from a m ast are con ­siderable, so build sufficient strength into the mast step and seal it against m oisture invasion. If your m ast is keel-stepped and the base o f the mast tenons in to the mast step, provide a drain hole from the bottom o f the m ortise in to the bilge. No m atte r what kind o f mast boot you put at the part­ners, some moisture will still run down the mast and into the mortise.

C A B I N S O L E S

Assuming your floor timbers are g lued in the bilge o f the boat, lay out the floor tim­ber lengths an d distances on cen te r (see Chapter 13) on 34- or %-inch plywood stock, and m ark the athwartships centerline and half-widths o f each floor tim ber m easure­m ent. The resultant layout represents your cabin sole, m arked upside down on the cabin sole stock. With a flexible batten, fair the two curved edges. T he nex t step is to provide bilge access through the center o f the sole. I like to have continuous access, 6 to 8 inches wide for the entire length of the sole as in Figure 23-2. Use a polyure­thane adhesive to fasten epoxy-sealed cabin soles to the floor timbers; adhesive caulking is less messy than epoxy and has good gap-filling capability. Place two beads on top o f each floor tim ber and gently lay the cabin sole over the floor tim ber grid. Place at least four fasteners per floor tim­ber, evenly spaced. Provide ventilation to the bilge by d rilling several holes in the bilge access plate. Screwing the sole piece on to the floor tim bers an d glassing the edges on to the hull creates an extrem ely strong floor tim ber/cabin sole gridwork.

Figure 23-2. Bilge access through cabin sole showing glassing at edges.

C O C K P I T S O L E S

C ockpit soles d iffer from cabin soles in that the cockpit sole almost always attaches to cleats fastened to the bulkheads and hull sides fo r the sim ple reason th a t i t ’s usually m uch h igher in the boat. The cock­p it soles m ust be carefully b o n d ed to the structures su rround ing them so th a t they are watertight, an d water must be able to ru n off cleanly w ithout pudd ling . My N ancy’s C hina design p resen ted a dicey p rob lem in th a t the d aggerboard tru n k starts ju s t forw ard o f the re a r bu lkhead , and forward o f the daggerboard trunk the bilge contains 385 pounds o f ballast, nearly filling die en tire space. It w ould be quite difficult to lim ber th rough the rear bulk­h ead an d alongside the daggerboard trunk , an d the bilge is inaccessible and extrem ely h ard to d ra in , ventilate, and m onitor for integrity. T he solution was to fill the bilge below the cockpit sole with two-part polyurethane foam and bond the

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epoxy-sealed sole in place with no o p en ­ings th ro u g h the top. A separate bilge co m partm en t an d access forw ard o f the daggerboard trunk allows the ballast to be cast in place and helps to ventilate that com partm ent. In general, if you can’t ade­quately lim ber and ventilate, fill com ­pletely with two-part po lyurethane foam and bond it solidly to the overlying piece. All parts m ust be scrupulously epoxy sealed before bonding.

L O N G I T U D I N A LB U L K H E A D S

T he longitudinal bulkheads form part o f the fram ing structure o f larger stitch-and-

glue designs, particularly those with decks. These are n o th ing m ore than large bulk­heads tu rned lengthwise in the boat.

The S urf Scoter cockpit has two longi­tudinal bulkheads runn ing from the tran­som to the rea r o f the p ilo thouse bulk­head. These form the sides o f the outboard m otor well, the sides o f the fuel tank com partm ent, and the adjoining side supports for the stern seats, and they pro ­vide bearing and fastening for the cockpit sole. T he th rust o f the o u tb o ard is dis­persed throughout the boat’s structure by these two cockpit longitudinals. All longi­tudinals are bonded into place with taped seam fillet jo in ts with the same care as in the m ajor athwartships bulkheads.

Figure 23-3. Cabin sole and floor timbers in the 29-foot Means o f Grace. Note that the cabin sole is glassed into the hull bottom at its edges, effec­tively tying into the hull the floor timber grid and the ballast keel that will eventually hang from that grid.

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Figure 23-4. The 22-foot Surf Scoter’s cockpit showing the integration o f both athwartships bulkheads and the two longitudinal bulkheads. The latter bulkheads support the outboard in its motcnrwell and define the cock­pit floor height. The fuel tank stows between the longitudinals.

B E R T H F E A T S

Berth flats are like large, horizontal bulk­heads. In m ost stitch-and-glue boats, they are positioned between major athwartships bulkheads. T heir ou tboard edges usually contact the hull, while their inboard edges term inate atop a longitudinal berth bulk­head. The berth flat, if it is fastened to the hull and to athwartships and longitudinal bulkheads, can add a great deal o f strength to the boat. It helps to transfer strains in the boat’s structure to o ther strong points in the hull.

Berth flats can be built o f K- o r %-inch plywood. If the flat is also functioning as a settee in the m ain part o f the cabin, op t for

the heavier stock. If the b e r th flat is in a forw ard V-berth area in a small boa t that will be used only fo r sleeping, /4-inch ply­wood will be m ore than adequate.

T he b e rth flat should be b o n d ed to the surrounding structures with epoxy fil­lets and taped joints to make it an integral part o f the overall boat’s structure. You can gain access fo r stowage and ventilation th ro u g h the longitud inal bu lkhead with pigeon holes o r doors, o r th rough rectan­gular cutouts in the flat. Be sure to provide adequate ventilation.

F I D D L E S

Fiddles re ta in things that are stowed on shelves o r flats, be they cushions, books,

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Figure 23-5. The floor grid o f a Means o f Grace, showing the berth longi­tudinal faces installed and bonded onto the cabin sole. The next step will be bonding the berth fla ts onto this structure, and bonding the outboard edge o f the fla t to the hull sides. Note the cleats at the outboard edges of the hull to support the berth flats.

o r pots and pans— they also trim , finish, and accent a boat’s interior.

I use dark hardwood for fiddles, and I d o n ’t usually epoxy-seal o r varnish them because over time they get scratched and gouged when the boat is used. If you use a b lond-colored wood, deep scratches will generally stain dark an d becom e very noticeable. Finish an d p ro tec t the wood with several coats o f Deks Olje, Seafin, or a similar oil. A few days after applying the last coat o f oil, I apply a coat o f Trewax fur­niture wax and buff the pieces. This finish looks a lo t like h an d-rubbed varnish b u t can be easily touched up with m ore wax. An annual waxing keeps the fiddles look­ing soft, sm ooth, and ship-shape. A nd by' using d arker mahogany-type hardw oods,

Figure 23-6. Bungs should run parallel to the grain o f fiddles.

the inevitable gouges and scratches w on’t be as no ticeab le as they m ight in a light- colored wood.

I attach the fiddles with countersunk

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holes and stainless steel sheet metal screws, 8 to 12 inches apart. Glue the wood bungs with a quick-setting epoxy o r a cyanoacry­late adhesive (instant glue) of the gap-filler type, and m ake sure that the grain in the wood bungs parallels the grain in the fid­dle. Cut the bungs ou t o f rippings o r end cuts from the fiddle stock to m atch the sur­rounding wood color. R unning the bungs with the grain parallel to the grain o f the fiddles looks less distracting to the eye the running it at 90 degrees to the grain.

A C C E S S A N D V E N T I L A T I O N

T he ability to access every section and com partm ent o f the boat is im portan t for inspection, m aintenance, and in the event of hull damage. Complete access also helps in an o th e r critical area: ventilation. As a basic rule, you can never have too m uch ventilation in a boat. The m arine environ­m en t is extrem e and can run from either cool an d m oist to h o t an d hum id , and e ith e r way you are dealing with a lo t o f m oisture. Provide m ultip le openings for ventilation, especially if the openings are sm aller than 12 square inches. For truly efficient ventilation, the access holes should be in the ends o f the com partm ent to establish an air flow pattern, providing fresh air a t one end and flushing stale air at the other, a breathing effect o f sorts.

I use several m ethods to provide ade­quate ventilation an d access. In vertical bulkheads, 1 cut large openings called pigeon holes. T he doorless p igeon holes n o t only provide good ventilation and access, bu t organize gear efficiently. Doors require ventilation slots with small bronze, stainless steel, o r wood covers. Cut from '/- inch plywood, wood covers can be gang-

Figure 23-7. A completed Means o f Grace berth fla t. Note the glassing at the outboard edge; the access liftout exposes the smooth epoxy-sealed interior. A ll components o f the hull must be finished to this extent.

p ro d u ced on a drill press with a sharp, b rad-po in t drill an d screwed over a hole cut in to the d o o r o r bulkhead. Occasion­ally, I cut ou t my bird-shaped logo, partic­ularly if the boat has a painted interior. You can m ake all sorts o f decorative patterns; use your imagination.

For storage access to th e b e r th and sole flats, use a rectangu lar cutout in the plywood with a couple of lK-inch-diameter fingerholes. Bolt a couple o f wood cleats on at least two sides o f the flat to support the cutout lid. Latches are unnecessary, since gravity and the w eight o f the cush­ions keeps the cutout in place. (On an off­shore boat, however, I ’d latch down the cutouts.)

Every cabin should have a t least two sources o f fresh air. In a b o a t as small as o u r 15-foot N ancy’s C hina, they m igh t include one cowl-type ventilator at the bow (which can also be used as a chainfall for

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the anchor rode) and a series o f vent holes drilled in the companionway drop slides. A larger boat like the Surf Scoter might want two cowl vents on the pilothouse roof and one cowl vent in the forw ard hatch . Two solar-powered ventilators w ould be even better; use one as an intake on the forward hatch and the second as an exhaust vent in the pilothouse roof.

D on’t skimp on the ventilation system for your boat; provide fo r worst-case sce­narios u n d e r d ifferen t w eather and wind conditions. A nd rem em ber, a boat is very m uch like a house: A lived in an d used house keeps a lo t b e tte r than one th a t is closed up and stale for long periods.

H A T C H E S

T here is a wide variety o f hatch designs to choose from. I use two basic types, both o f which are easily made. An ideal choice for the waters of the Pacific Northwest is a hard­wood box with finger-jointed o r dovetailed co rn e r jo in ts , fitted with a translucen t Lexan (polycarbonate) or solid wood top.

If you choose a Lexan top, overbore p ilo t holes in the Lexan at least one drill size larger th an the fastener diam eter. Polycarbonate expands and contracts with tem peratu re changes and overboring the pilot holes allows the Lexan to move with­ou t cracking around the fasteners. Bed the Lexan in a po lyurethane b ed d in g com ­p o u n d . Applying a clear p rim er to the Lexan will he lp the caulking com pound adhere to it. Set the screws with hand pres­sure evenly a ro u n d the hatch fram e. Fasteners every 3 inches is the m inim um for b ed d in g %-inch Lexan; %-inch Lexan requ ires a fastener every 4 inches. If you d o n ’t like the look o f the Lexan edge, trim it with a half-round o f hardw ood. If the

Figure 23-8. Hatch section types.

clear hatch does no t ensure sufficient pri­vacy, light sanding with 220-grit sandpaper followed by a scuffing with Scotchbrite pads will frost it, while still allowing plenty o f light below.

For the solid-wood top, bu ild the fram e first and ro u t the perim ete r with a rabbet bit. Set the hatch fram e upside down over a piece o f K- o r %-inch plywood stock an d m ark the outline o f the frame. Cut along the outline, carefully dry fit the piece, and epoxy the top into place.

I like to make a ha tch cover m ore attractive by cu tting a series o f small grooves in the hatch with a table saw and a k e rf o r dado blade. G luing a p iece of contrasting wood in to the grooves creates an inlaid hatch with the w atertight integrity o f solid plywood. Carefully seal the ha tch with epoxy and apply a m ini­m um of six coats o f varnish.

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Figure 23-10. Taco Metals extrusion hatch slides.

W ith m in o r variations, the same scheme can be used to build curved hatch tops. The saw kerfs allow the hatch to bend in an arc. For hatch slides, dado pieces o f d im ensional teak and attach a Taco slid­ing extrusion for a smooth slider.

For hatches on the foredeck and cab- intop, use two sets o f hatch hinges, placed forward and aft, so that the hatch can be raised in either direction, allowing for the best ventilation by acting as a wind scoop.

To reinforce the hatch opening, I use a two-part carlin system. Before the decks are lam inated in to place, beam s are installed to define the p e rim e te r o f the opening . T he deck is th en g lued and fas­

Figure 23-11. Hatch carlin system for a Lexan hatch.

ten ed over the fram ing. After the decks have been sheathed, the hatch open ing is cu t out, a task easily accom plished if you first drill small pilo t holes from below, up th ro u g h the deck at each o f the fo u r cor­ners. Frame the opening with hatch carlins fastened directly in to the framework. The hatch cover overlaps the carlins, and with a b it o f foam -tape w eather stripp ing on its bo ttom edges, it works very well. For off­shore sailing, you might fit another wooden framework around the outside o f the hatch; generously scuppered , this functions as a wave break and protects the hatch.

D O O R S

For stowage areas too large o r too visible for p igeon hole access, you may have to build cabinet doors. Most o f the cabinets in o u r stitch-and-glue boats are built from sheets o f plywood th a t ru n in to co rn er blocks at their edges. This way, the plywood removed from the cutout in the cabinet front can be re tu rn ed to its place o f origin as a cabinet door. If you keep track o f the cutouts, your doors will even m atch the grain o f the sur­ro u n d in g bulkheads. Flal h inges seem to

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work best if they are screwed o r bo lted through the door casing.

For com panionw ay doors, I stick to th ree choices: d ro p slides fo r sailboats, sliding doors for p ilo thouse boats, and hinged doors for boats without room for a sliding door. Each has advantages and dis­advantages. D rop slides for a sailboat com­panionw ay are probably the easiest, strongest, an d safest alternative. Cut the door shape out o f the bulkhead. Frame the o p en in g with hardw ood slides, tapering the sides o f the open ing slightly (about 'A inch narrow er a t the bo ttom than a t the to p ). Be sure to taper the in terior edge of the hardw ood strips to allow the plywood cutouts to slide easily; if you d o n ’t, the drop slides jam and stick.

C ut the d ro p boards into easily h an ­d led sizes, with a 45-degree bevel in the jo in ts betw een boards to keep rainw ater ou t o f the boat. Be sure to scupper the bot­tom gutter so the slides d o n ’t sit in a pool o f water.

O n p ilo thouse boats I m ake sliding doors whenever possible. They work well if the sliding apparatus is a t the top o f the door. W hen a door slides on a bottom track, it always seems to stick an d jam . W ith the sliding mechanism on top, the bottom track simply keeps the bottom o f the d o o r from swinging out. Usually th e re ’s n o t en o u g h beam in the boat to remove the door by slid­ing it ou t at one end, so make the door track rem ovable by rem oving the screws in the

Figure 23-13. Drop slides and drop boards.

upper sliding track. Taco Metals #A52-0037 alum inum extrusion is available in 12-foot lengths and can be cut and shipped by UPS in shorter lengths. I use #40-601 WN nylon slides in the track. Use the bulkhead cutout for the door blank, and frame the door with 1/4-inch-square stock d ad o ed o u t fo r the bulkhead thickness.

I use a similar concept for hinged doors by build ing a hardw ood jam b aro u n d the bulkhead door cutout. You want to be sure the finished door is larger than the cutout, so use a m ite red trim a ro u n d the perim e­ter o f the cu to u tju st as you m ight have for the in terio r cabinet doors. H ang the door with removable hinges to allow unshipping in nice weather.

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My preference for finishing surfaces is to paint all the exterior, except such trim as rubrails and toerails, and varnish all the interior, except for the overheads.

C H O I C E S O F ’ P A I N 'T S Y S T E M S

For a stitch-and-glue boat, you have four basic classes of paints to choose from:

Alkyd enamel paints are all single-compo­nent, oil-based paint systems. You may be familiar with them already, because they’re the enam el paints used in houses for porches and decks.

Epoxy paints are the distant cousins o f the epoxy system with which you assem bled your stitch-and-glue boat.

Acrylic u re thane pain ts are two-part sys­tems. T hey’re very close relatives o f the paint on your new car.

Linear polyurethane (LPU) paints are also two-part systems, but they’re h a rd e r and more durable than the acrylic urethanes.

For your purposes, I would avoid the alkyd enamels, as their compatibility with epoxies is questionable. I do believe you could choose a paint from this family and use it successfully, b u t you’d be lucky to strike il righ t first time. It often appears that there are chemicals in alkvd enamels th a t react badly with the epoxy systems used for the b o a t’s structure . T he m ost com m on com plaint is thal alkyd enamels applied over epoxy take longer than nor­mal to cure— or will not harden at all.

T he best chance o f success comes when you coat the boat with a conversion p rim er coat before pain ting with alkyd enam el. I would use several rolled-on or sprayed coats of epoxy DP prim er for this conversion coating. M ore about this prim er follows later in this chapter.

While the alkyd enam els d o n ’t always like the boatbuild ing epoxy resin system, the epoxy DP prim er seems quite compati­ble. Still, all in all I would avoid the alkyds as they are not a certain path to success.

An additional word o f w arning here. T here is an o th e r class o f paints called sin­gle-pack polyurethane coatings, or oil-mod- ified polyurethane. While the paint m anu­

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facturers may re fer to them as poly­u re thanes, you shou ld be well aware that they are n o t th e sam e th ing as linear polyurethanes, which cure by the interlink­ing of molecules in a chemical reaction. In short, fo r topside paints I ’d advise you to avoid any paint o r clear covering that doesn’t require the mixing of two parts.

Epoxy paints work very well as primers and conversion coats, b u t they’re n o t the best for final coatings. T heir biggest prob­lem is that they chalk quite noticeably out­doors. The surface oxidizes somewhat and if you ru b the w eathered p a in t surface your finger will com e away with a powdery coating o f pigment.

For this reason, I d o n ’t recom m end your using an epoxy-based paint system for your final surface coating— unless you approach the whole concept with your eyes wide open. I add this because, depending on your personal requirem ents, there is a case to be m ade fo r paints th a t chalk. It’s practical, even if it isn ’t very “yachty.” Commercial fisherm en do it, and you can b e t your life they d o n ’t spend any m ore time or m oney on upkeep than they have to—yet they want to protect their boats as well as they can. I ’ll have m ore to say about this in a bit.

T he acrylic u re th an es are h a rd and durable, and quite easy to touch up when dam aged. I use a lo t o f them in my shop, th e two m ost com m on being PPG’s D eltron an d Concept. Both are as easy to spray as any you’ll find, and both give con­sistently good results.

T he downside to Deltron and Concept is that they have to be sprayed. And spray­ing a finish is, in its own way, ju s t as com­plicated as bu ild ing boats. A nd b ea r in m ind that these acrylic urethanes contain isocyanates. T hat means they’re quite dan­

gerous to your h ea lth if you b rea th e the fumes. W hen you’re spraying these paints, organic vapor respirators offer only mini­mal protection. I t’s better to have a piped supply o f pressurized fresh air fo r your face mask.

L inear polyurethanes, o r LPUs, are the highest o rder o f evolution of paint fin­ishes. They can be quite finicky to apply, an d they perfo rm best w hen sprayed, although the best m anufacturers offer spe­cial form ulations fo r ro lling o r b rush ing as well. LPUs work very nicely over epoxy resins, with o r w ithout a conversion coat­ing o f epoxy prim er. You should get very good results if you follow closely the m an­u fac tu re r’s recom m endations an d do all the groundwork necessary.

But they’re th in , h a rd coatings, and they’re so glossy that they’ll show every lit­tle im perfection in the surface they’re cov­ering. However, th a t glossiness translates in to long-term durability, so if you can manage to apply a coating o f LPU satisfac­torily, you’ll have a pa in t system th a t will last as long as any possibly can in a marine environment.

Incidentally, LPUs also con ta in iso­cyanate, an d m ust be h an d led with great care. In my shop, we pipe in fresh air from outside. T he system com prises an oil-less com pressor and hoses from there into the pain t sprayer’s face mask. I t’s very im por­tan t to avoid any contact with the vapors or th e p a in t itself. We use disposable Tyvek suits, d isposable gloves, and a full-face mask air system.

In my shop, we do m ore spraying than hand-pain ting because i t ’s faster if you know what you’re doing. In the case o f a non-professional, though, I d o n ’t believe i t’s worthw hile accum ulating the experi­ence you need to spray paint. So your best

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option is to use a pain t system that allows for application by hand.

T he best way to do this is to roll and brush. Properly done, this takes two peo ­p le working side by side, bo th well p ro ­tec ted with respirators. O ne rolls on the p ain t in sections o f roughly 24 inches to 30 inches square. T he o th er uses a foam, throwaway brush to tip o ff the freshly ro lled p a in t with long even strokes. T he idea is that the ro ller evenly applies paint without runs, and the brush sm oothes ou t the roller stipple pattern.

Apply a thin coat of paint and plan on two coats. T he final result can be very near professional spray quality. You’ll have to work fast and be organized, b u t pain ting this way can be done by persons with very little experience.

O ne o ther possibility when it comes to painting with LPUs is to p repare the boat as com pletely as possible and then h ire a professional p a in te r to finish th e jo b . T here are qu ite a few peop le out th e re with experience o f pain ting cars and trucks who have the eq u ip m en t to do a good jo b fo r you. In the long ru n , it will be money well spent.

E X T E R IO R S U R F A C E S

T he ex te rio r o f the boat is the m ain sur­face that is going to take the b ru n t o f the abuse from weather and docking. W hat we need h e re is an easy-to-manage surface th a t will be h a rd and du rab le enough to absorb the knocks o f daily use an d still look good.

Painting is, o f course, one o f th e last stages of building a boat and I find myself developing a love-hate re la tionsh ip with the boat. I ’m always happy to be done with th e construc tion work, b u t I know from

experience th a t th e re ’s a long road still ahead.

O n a 22-foot b o a t such as o u r S urf Scoter, we’re talking abou t eigh t days o f work, including p rim er coats—and th a t’s when I spray ra ther than using a roller and brush. A nd d u rin g th a t session I will almost always run into trouble that calls for a re-spray.

W hat I need is a paint system with reli­able, pred ic tab le characteristics, so I can use it w he ther i t ’s 32° o r 90°F outside. It should set up o r cure quickly, to avoid hav­ing the shop sh u t down any lo n g er than necessary. It should be good and durable, and it should look like a million dollars.

But w hat I n eed isn ’t always what I get. I t’s not easy to com bine all these fine qualities in o n e pa in t system. W hat it boils down to in the en d is e ith e r acrylic ure thanes o r linear polyurethanes (LPUs). For roller-and-brush application, as stated above, choose LPUs. You may be acquainted with the nam es o f a couple of LPUs. Awlgrip and Sterling are two o f the best-known. Both o f them have fo rm ula­tions for application by hand as well as by spray gun.

If you’re feeling adventurous, you can always experim ent. I fin ished one o f my beach cruisers with an epoxy p rim er that norm ally acts as an u n d e rco a t fo r o th e r paint systems. It’s m ade by the Ditzler Paint Company, a division o f PPG Paint. Called DP Primer, it comes in black, white, gray, green- gray, and red oxide. I t ’s a two-part system and cures in any weather. You can spray it, brush it, o r roll it on.

These DP Prim er paints are classed as “non-topcoat type,” because they d o n ’t necessarily have to be covered with a top­coat for a durable finish. T heir own finish is h a rd and durab le , an d can easily be

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Figure 24-1. Paint work underway on Czarinna, a 35-foot, twin-screw powerboat. Most of the woodwork has been finished, and all the freshly painted areas have been masked off. Pilothouse windows will be cut out once painting is completed.

pa in ted over la ter on if necessary. DP Prim ers give a sm art satin surface that doesn’t emphasize m inor imperfections as a glossy finish does.

The beach cruiser was 28 feet long and6 feet wide, powered by a 10-horse inboard diesel. I p a in ted the hull DP white. T he decks and cockpit were DP gray. If you’re p rep a red to forgo the trad itional glossy yacht finish, you could use a DP system like the beach cruiser’s and save yourself a lot of preparation and finishing time.

My confidence in the DP P rim er sys­tem has increased over the years. I t’s the base pain t that has gone on my duckboats

for m ore than 10 years. DP P rim er will chalk a b it as it ages— a tendency o f all epoxy-based paints—but it doesn’t seem to compromise their durability.

However, having said that, 1 realize th a t the urge to p u t a perfectly sm ooth, glossy surface on your boat can be quite overwhelming. So I guess we’d better dis­cuss how to accomplish that goal.

Protecting your Epoxy

O ne o f the best reasons to pain t as m uch of the exterior of your boat as possible is to p ro tec t the epoxy sealing and shea th ing

P a i n t i n g

of the wood from degradation by ultravio­le t rays from the sun. T he epoxy with which your boat is built, and which it relies u p o n fo r its streng th , does n o t have any natural protection from the sun’s rays.

For th a t m atter, if we co n tin u e to dep le te the ozone layer, h u m an beings won’t have any protection from ultraviolet rays either. Ju s t as we m ust p ro tec t o u r­selves with sunscreens, so we must protect the epoxy. T he best way to do this is to cover it with paint, which is opaque. But if you want a clear, varnish-like finish, you m ust cover the epoxy-sealed wood with a varnish o r o ther clear coating that contains ultraviolet filters. And, because no clear finish can block ultraviolet rays as effi­ciently as paint, all clear coatings must be renewed annually to provide adequate pro ­tection for the epoxy.

I f this sounds like a lo t o f work, it is. So be very careful w hen you consider fin­ishing a part o f your boat as brightwork. You can spend an awful lot of time keeping that finish up.

Epoxy is such a m agic m aterial that people sometimes find it difficult to believe how susceptible it is to sunlight. But degra­dation is fast and deadly. You can see this for yourself in a simple experiment.

Coat a p iece o f plywood with epoxy resin and allow it to cure. Place it outside where sunlight can reach it. Place another piece of plywood over at least a half o f the coated piece. After ju s t a couple o f days, have a look at your sample. T he part that was covered will be quite a different color from the part that was exposed to the sun.

The Effect o f Paint Color

A n o th er good reason why you p u t finish coatings on your boat is to p ro tec t the

epoxy from heat damage. If you paint your b oat a dark color, such as b lue, g reen , o r black, you can actually sh o rten its life. Epoxy resins can be quite heat-sensitive and it’s best to keep them as cool as possible.

I d o n ’t come across this problem m uch h ere in the Pacific Northwest, bu t I still find th a t a dark-pain ted b o a t requ ires a t least twice as m uch a tten tio n to stay looking good as its lighter-colored sistership.

T he co lor o f the pa in t makes a differ­ence in surface tem perature o f as m uch as 40°F on a sunny day. My own boat, an Arctic Tern, 22-foot 8-inch sailboat, was originally a light gray. A fter fo u r years, the original pain t was in good condition, bu t my curios­ity got the better o f me and I painted h e r a dark blue. Very smart, b u t . . . .

A year later, d u rin g h e r annual hau lou t, 1 looked closely a t th e hull sur­face. W hen she was gray, the hull was fair and sm ooth. Now I could see the pattern o f the fiberglass sh ea th in g showing through, o r telegraphing, in the topsides. The only difference was the color, and one year o f being heated by the sun.

So I co n d u c ted an ex p e rim en t on a 92°F day. I p laced a th e rm o m ete r on the dark-blue topsides and got a recording o f 142°. I then placed the therm om eter on a nearby surface pain ted off-white. It regis­tered 113 degrees. Quite a difference.

Now epoxy resin can have a h ea t deflection tem p era tu re o f ab o u t 125°F. T h a t’s the tem p era tu re at w hich cu red epoxy begins to deflect, o r move, u n d e r stress. It can also have a glass transition tem p era tu re— the tem p era tu re a t which cured epoxy begins to behave m ore like a rubber com pound than like hard epoxy— o f ab o u t 150°F. So an epoxy-built boat painted in dark colors is very m uch oper­ating in a range o f tem peratures that could

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have ra ther frightening consequences.My experience with boats with dark

exteriors is th a t they exhib it, to various degrees, the following traits:

First, they have a noticeable tendency to show print-through—the pattern o f the fiberglass cloth underneath . They will also show raised grain in the hull surface.

Second, they will show quite clearly any scarf jo in t in the plywood, an d any in te rru p tio n in th e wood grain o r pat­te rn o f th e various com ponen ts o f the hull. They will em phasize filled fastening holes, co rn er blocks, and any jo in t in the structure.

Let m e m ake it c lear th a t w hat we’re talking about here is looks, n o t structural integrity. I have never seen a to tal s truc­tu ra l failure o f a stitch-and-glue epoxy composite boat caused by the color o f the paint. It s ju s t that if your pain t jo b is dark, it will look in n eed o f a tten tio n at least twice as quickly as a lighter boat will. As a m atter of fact, even light surfaces will show som e o f the symptoms m entioned above, bu t to a far less noticeable degree.

T he m oral is th a t you could be wast­ing your tim e spend ing countless hours sanding and sm oothing if you’re going to p a in t your boat a dark color. You have to decide for yourself.

O f course, th e re are o th e r causes, besides d ark pain t, o f p rin t-th ro u g h o r te legraph ing in the hull surface. My own experience has uncovered the following fairly consisten t causes o f exaggerated telegraphing:

Painting a boat too soon after applying epoxy and glass. T he epoxy should cure for at least a m onth, preferably two months.

Moving the freshly painted boat ou t into

the hot sun too soon. Wait at least a m onth. T he longer the paint cures, and the shorter the initial periods of exposure to sun, the better.

Building and painting in an unheated shop in winter. T he cooler and m ore hum id the weather, the m ore likely it is that the hull will show telegraphing.

Very th in coatings o f prim er and finish coat. Fatter coatings hide joints and patterns better.

Overcoating too soon. Allow a generous cure time between coats.

Using a soft, m ore flexible epoxy for the exterior sheathing. As a general rule, com paring a couple o f well-known epoxy systems, the m ore h ardener in the mix, the m ore flexible the system. It sounds paradoxical, bu t an epoxy with two parts o f resin to one part of h ardener would often be m ore flexi­ble than another with five parts o f resin to one part o f hardener. T he lat­ter, less flexible epoxy system, will hide print-through better.

A nother way to help reduce telegraphing is to post-cure the epoxy. This is an attem pt to simulate the natural processes your boat will be subjected to in use, the heating and cooling cycles th a t h e lp settle the epoxy into its final form.

T hink o f th e en v ironm en t your boat will be subjected to. T h at m ight m ean freezing cold w eather in w inter and hot, h um id w eather in sum m er. I t m ight also m ean sudden changes, w hich can inflict m ore strain th an longer, m ore gradual changes o f tem perature.

Your epoxy has to sh rink and stretch to accom m odate these extrem es, an d if you can m ature it by putting it through its paces before you apply the final coats o f

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paint, your chances o f achieving p erfec ­tion are m uch better.

O n e way to do this is to use in fra red heaters during construction. I use a quartz in frared h ea te r th a t I bought from the Grainger Co., and move it around the boat in 30-minute o r longer sessions. A nother m ethod that I’ve been exploring is to use a black epoxy p rim er on boats small enough to move outside on a moderately sunny day, le tting the sun do ou r heating work for us.

You can buy from your epoxy supplier some small strip therm om eters to tape on to the surface o f the hull. Be careful not to let the tem peratu re exceed 140°F; but anything below that will be helpful in post­curing the epoxy.

Some epoxy m anufacturers make spe­cial epoxy coatings th a t need to be post­cured in ovens, o r perhaps with ou r black prim er in sunshine, up to and in excess o f 140°F. They can be very tough and strong, bu t my feeling is th a t am ateurs h ad best leave them alone.

Secrets o f a Perfect Paint Finish

H ere are the steps y ou’ll n eed to take to ensure perfec tio n — or a t least a sm ooth and fair finish:

Do the best and smoothest jo b you possi­bly can o f glassing the hull.

Sand lightly, and after applying a layer o f epoxy mixed with microballoons on the unfair glass overlaps, sand again.

Now reseal the entire structure with Cabosil-thickened epoxy resin. This layer will serve both to seal and to prime.

Lightly sand the hull with 80-grit sand­paper on a random orbit sander—no

m ore grinding from here on in. Take care no t to sand into the fiberglass cloth. If you do, reseal the area with ano ther rolled-on coat of epoxy.

Now is the time to post-cure the surface with infrared heaters o r sunshine. If you choose not to post-cure, move right along.

Roll on the first conversion coat of DP 40 epoxy prim er and allow it to cure.

Now go around the hull looking for defects in the finish. Fill them with a m ixture o f epoxy resin and microbal­loons or Microlight fillers if they are deep, o r with a lacquer glazing putty if they are shallow. This putty is avail­able at an automotive paint store.

Sand the filled spots smooth with 150- grit sandpaper. If you used Microlight filler, you now need to reseal the sur­face with unthickened epoxy resin to ensure a uniformly sm ooth surface.

Sand the whole hull again to a matte surface with 150-grit paper.

If you’re now happy with surface, and you have m anaged to m aintain the epoxy prim er on most o f the surface, you can sand the entire boat with 220- grit paper and prepare for the final paint coats.

But if you find the surface still needs some work, you’ll have to re-prime. We use an easily sanded prim er called K36 Prima, m ade by PPG. Prima likes to be sprayed, bu t you can use the roll-and- brush technique m entioned earlier.

Sand the surface with 220-grit paper and you should be very close to perfection. Any rem aining flaws should require only m inor filling with glazing putty. Sand the putty smooth with 220-grit paper also.

Now apply a final coat o f DP 40 prim er

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as a sealer and prim er for the final coats T he need here is for a smooth surface devoid o f any areas of poros­ity. If you roll-and-brush this last layer of primer, you will want to allow it to cure at least overnight.

T hen sand it very lightly with 220- or 320-grit paper, depending on how fine a finish you want, and you’re ready to apply the final paint coats.

If you sprayed the DP 40, allow it to cure for at least three hours. Then, with­ou t sanding, go into your final sprayed-finish enamels.

If you’re spraying on the final coats, you’ll need at least three medium-cov- erage coats with at least one hour between each coat. T hat’s time enough for the underlying layers to cure without causing a problem with solvent entrapm ent.

If you’re rolling and brushing your final coats, you’ll need to apply a coat of norm al thickness and let it cure—at least overnight. Then scuff it lightly with a 3M Scotchbrite pad, and apply another coat the next day.

Som e U sefu l Rules

In my shop I have set some rules for the application o f all tw o-com ponent epoxy, acrylic, o r polyurethane paints. T he first is to use exactly the p ro p e r ratio o f paint to catalyst. Always follow the pain t m an­u fa c tu re r’s recom m endations in every respect.

T he second rule is th a t you canno t overstir the paint-and-catalyst m ixture. After stirring adequately, as instructed by the m anufactu rer, le t the m ix ture sit, o r induct, and then stir it again after several minutes. D on’t let the instructions on the

can m islead you in to th ink ing th a t no induction time is needed. It is.

T he th ird ru le is always to strain the mixed and inducted paint before using it. You’d be surprised what will show up in the strainer sometimes. Fourth, always “push,” o r accelerate, the p a in t to the lim it sug­gested by the m anufacturer. T he faster it sets up, the b e tte r for the project and the less chance for contamination.

T he fifth rule is to avoid any contact with LPU. D on’t breathe it, d o n ’t touch it. I’ve m entioned it before, and I m ean it. I use solvent-proof gloves, Tyvek spray suits, barrier cream on my face and particularly around my eyes, a spray sock over my head, and a separate fresh-air system blowing in filtered air from outside the shop. Goggles are im portan t, o r som e kind o f safety glasses, to prevent sprayback getting into your eyes. A full-face mask unit for a fresh air system is a good idea, too. LPUs and acrylics contain isocyanates. T hat’s part of what makes them beautifu l and durable. T hat’s also what makes them killers.

The sixth rule is n o t to use sandpaper th a t’s too sm ooth. Most tw o-com ponent paints need a little “to o th ” to hang on to. I have found it best to stop at 320-grit sand­p ap er for most pain t systems, and in a lot of cases 220-grit will suffice.

Rule seven is to use tack cloths before painting to remove every last trace o f dust from the sanded surface.

Finally, som e food for thought. T he adhesion o f the coat o f paint you’re apply­ing is only as good as the adhesion of the undercoats. It may seem red undan t even to m en tion this, b u t I ’ve seen painters who believed that tw o-com ponent paints were some magic form o f glue that would help flaking undercoats stick themselves to the boat. Forget it. All you’ll have is a

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coat o f paint over loose layers o f marginal undercoats, ready to peel off at th e first decent bump.

A P P L Y I N G N O N -S K ID S U R F A C E S

You can apply non-skid finishes by han d or by spray gun. L et’s first look a t how to do it by hand.

You apply non-skid after you’ve do n e the smooth painting on the deck and cock­pit surfaces. Let the pain t cure for at least two days. T hen define th e perim eters o f your non-skid areas with masking tape.

Lightly sand the non-skid areas with 220-grit san d p ap er un til you have a un i­formly m atte surface with no glossy spots showing. For best p a in t adhesion you should always sand between layers, and for the final finish coat you can S cotchbrite between layers.

Now mix up the non-skid paint o f your choice. Make quite sure you’ve mixed both com ponen ts thoroughly befo re you add the recom m ended percentage o f non-skid com pound. I f you’re like me, you’ll stir in an extra 25 percent of non-skid. T hat gives you a slightly h igher profile non-skid.

You can roll this pain t m ixture on, bu t keep rem inding yourself to stir it very fre­quently to ensure even coverage. Apply at least two coats to get the right texture, and d o n ’t b o th e r to b ru sh o u t th e stipple in this case. Wait for about two hours between coats. Remove your masking tape as soon as you can do so and leave a nea t edge. If you forget, an d leave it to bake on overnight, you’ll be very, very sorry, as the p a in t will creep u n d e r the m asking tape- and leave a rough edge.

You can also sprinkle non-skid additive over a freshly rolled-on coat o f paint to cre­

ate non-skid. Be sure to vacuum o ff the excess non-skid m aterial before rolling on add itional coats o f p a in t to seal the non- skid com pound.

O r you can m ix up a p a in t an d non- skid additive m ixture and spray it on your surfaces. Several light coats done in multi­ple passes can yield the best results o f all the non-skid application techniques.

IN T E R IO R F I N I S H E S

My preference for interiors is an all-bright Finish (th a t is, an all-clear finish) with a painted overhead. Painting the overhead a light color goes a long way toward reflecting light back into the interior. It keeps things feeling b rig h t an d airy. If you d o n ’t pa in t the overhead, the boat’s in terior can some­times look pretty dark and oppressive.

I p a in t in advance the undersides o f the cabin top and decks with the same type o f system I ’ll be using on th e rest o f the interior before fastening them to the deck fram ing structure.

W hen painting in advance, I first seal th e panels o f plywood with epoxy resin. W hen that has set up, I sand with 220-grit p ap e r an d apply the coats o f paint. T he roll-and-brush m e th o d works well here , bu t it always takes two coats to give m e the coverage I want.

A fter th e p a in t has cured , I sand it lightly with 320-grit paper. The pre-pain ted panels are then cu t to shape, and ready to apply. Incidentally, d o n ’t neglect to th ink the process through thoroughly—you need to have all plywood jo in ts and seams in the fin ished overhead land ing on structu ra l framing.

For gluing on these pre-painted panels I use a white polyurethane bedd ing com­pound such as Sikaflex or 3M’s 5200 com­

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pound. I fasten the overheads with screws into the deck framing and quickly clean off the squeezed-out bedding com pound with clean rags and m inera l spirits, an d th en continue with the balance o f the deck and overhead layers, lam inating with epoxy and screw-fastening into the framing.

Finally, I have surfaces th a t are painted, sanded, and at the same stage of finish as the rest o f th e in terior. For the final finish I now spray several coats o f clear acrylic ure thane over the entire inte­rior, bo th the epoxy-sealed brightwork and the painted overheads.

In one good day o f spraying I can apply four to six coats o f clear finish. I p re ­fe r to use a flatting ag en t m ixed in to a clear finish to create a satin appearance. I th in k a sm ooth glossy finish looks quite

garish down below. It certainly doesn’t suit my tastes.

I apply the flatted clear finish on every surface, includ ing the p re-pain ted over­heads. T he result is a uniform, satin finish.

If you’re applying your finishes by hand , you’ll find you can achieve similar results with th e roll-and-brush m ethod , although it will take you m uch longer.

As with so many aspects o f boatbuild ­ing, p repara tion is everything to the final result. Make sure your surfaces are clean and dust-free. Lightly wet down the shop floor to help pull excess floating dust from the air. Use a tack rag ju st before painting o r varnishing, and use clean, fresh rollers, brushes, paint-mixing tubs, and tools. The only o th e r things you need are a lo t of patience, and a similar am ount of luck.

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E X T E R I O R T R I M

Toerails, rubrails, caprails, and o ther trim can make or break the appearance and fin­ish o f a boat. If the trim is ou t o f scale, the boat will appear ou t o f p roportion . If the trim work is sloppy, the cosmetic effect will cheapen the overall quality o f the boat.

All the trim on my boats shares one thing: It is all added after the basic boat is completed and painted. There are two rea­sons fo r delaying the trim un til afte r the final painting. O ne is to achieve a uniform and fully protective paint job; the second is to m inim ize the ted ious jo b o f m asking required before painting.

Each design has its own trim details and scantlings, bu t the basic procedure is the same: p rem ach ine the parts, dry fit them for accuracy, an d finish the final sanding and prefin ish (coatings) before installing them . My goal is to only m ini­mally to u ch the trim afte r I ’ve installed the pieces with screws o r bolts, bunged the fastener holes, and chiseled the bungs off flush with the surface. Most o f that fin­

ish work is to simply apply an o th e r cou­ple o f coats o f oil, Cetol, o r varnish to seal the bungs.

It is becom ing increasingly difficult to buy long lengths o f m ahogany and teak to use for exterior trim, so the alternative is to sca rf the stock to ap p ro p ria te lengths. W hen scarfing, always consider the ru n of the g ra in in the p iece o f trim , an d align the scarfs so they shingle past obstructions instead of catching them (see Figure 25-1).

R ainw ater an d splash will ru n across decks, course over the top edge o f a rub rail, an d shee t down the topsides, d iscoloring the topsides paint. To p reven t this, cu t a d rip groove ab o u t Vs inch wide and % inch deep in the lower edge o f a rubrail.

Place fasteners a t least every 6 inches along the len g th o f the trim , an d always bed the trim in a po lyurethane caulking com pound. T he woods o f choice are teak for varnished, Cetoled, o r oiled trim , and m ahogany fo r trim th a t is m ore cosm etic and e ith er varnished o r epoxied and var­n ished. O ak an d locust are excellent choices, too, if you can find them . W hatever wood you choose, bear in m ind th a t the first pu rpose o f trim is to bear

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Figure 25-1. Align scarfs so they shingle past obstructions instead of catching them.

chafe, so consider how the wood will stand up over the long run : Will it stain dark when damaged o r scuffed? Will those blem­ishes affect the overall appearance o f the boat? I generally shy away from the light b lond oak o r locust woods for that reason, opting for the darker mahogany or teak.

E x terio r trim , such as handrails and steps, shou ld always be m ade o f tough hardw ood. Teak is ideal because it with­stands neglect b e tte r th an m ost o th er woods, and when oiled always looks good. Safety aids such as handrails should be through-bolted whenever possible.

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Figure 25-2. A saw-cut drip groove in the rubrail will prevent topsides discoloration.

H A R D W A R E

T he hardware you install on your boat will have to appeal to your own sense o f aes­thetics above all else. Beyond that, it should be practical and affordable. I prefer to use plain bronze whenever possible, andI d o n ’t polish it because I prefer the light- green patina o f oxidized bronze. However, th e re are som e things th a t ju s t are no t available in bronze, and in such cases I use stainless steel.

W hen you use stainless steel, use the h ighest g rade available. Type 304 (som e­times referred to as 18-8) is good, but type 316 is m uch m ore resistant to crevice cor­rosion. Type 304 will ap p ea r to ru st and

look less th an sh ipshape afte r a while. If you buy stainless steel hardw are, look for sm ooth an d po lished surfaces to reduce the problem s o f crevice corrosion. W hen used underwater, stainless steel is particu­larly vulnerable to crevice corrosion; better to confine its use above th e w aterline o r inside the boat.

All m arine hardw are is frighteningly expensive, b u t th e re is no substitu tion . N onm arine hardware ju s t doesn’t hold up as well. You’ve come this far in the building project, and you owe it to yourself to fin­ish your b o a t o ff with the best hardw are available.

Coat an d seal th e edges o f all h a rd ­ware-fastening holes with epoxy. I keep a supply o f p ipe cleaners to coat the in teri­ors o f the smaller holes. Any breach in the epoxy sealing will later come back to haunt you, so be thorough.

Use dirough-bolts to m ount hardware w henever possible, and m ake sure high- load items such as cleats and m ooring bitts have bronze o r stainless steel backing plates. O ne-eighth-inch silicon bronze plate stock works well for customized back­ing plates. It drills m uch easier than stain­less steel and can be cu t with a jigsaw or bandsaw with a dull w ood-cutting blade. Bed the hardw are with polyurethane bed­ding com pound , and wipe off the excess caulk with a clean rag and m ineral spirits.

I use stainless steel bolts with nylon- insert, aircraft-type nuts for attaching most hardw are. T hese nuts d o n ’t n eed lock washers and w on’t back off the threads as th e b o a t ages. Use large flat washers o r backing plates to help spread the load over as large a surface as possible, and bed the hardware meticulously. If you’ve got room, use the larger-diam eter fender washers to help through-bolt backup loads.

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How you power a boat has everything to do with the u ltim ate enjoym ent o f the craft. G one are the days when boats were either hum an-pow ered o r sail-powered. Today, even if you are building a sailboat you can­n o t ignore the need for mechanical propul­sion as a backup system.

Do you n eed re d u n d a n t o r spare pow er fo r your boat? I th in k the answer will have to be addressed by each individ­ual. In my own sailboat, a 23-foot Arctic Tern, I have a 10-hp diesel inboard auxil­iary. W ith the sails, the diesel, and a good anchor, I can probably deal with m ost problem s that m ight com e up. Insist on a good, re liable pow er p lan t, adequate g ro u n d tackle, an d a VHF radio to help you if the worst comes to pass. A nd m ain­tain the engine religiously. If you neglect eng ine m ain tenance, expect bad karm a; she will in d eed let you down w hen you might need her most.

Although stitch-and-glue designs have no special in b o ard o r o u tb o ard pow er requ irem ents, I have developed som e m ethods that make inboard engine instal­lation a little easier. E ngine beds are the first issue. You will need to do a b it o f lay­

o u t work to accom m odate th e shaft and eng ine bed angles. Generally, m odern m arine engines require the m otor m ounts to be in line (parallel) with the propeller shaft angle. Cut an oblong hole in the keel o f the boat at the expected position o f the packing box; the hole will help locate the shaft line. S tretch a string from the posi­tion o f the aftm ost strut o r shaft bearing to he lp m easure th e shaft angle. T he en g in e m an u fac tu re r will ind icate the m axim um allowable shaft angle, usually n o t m ore than 15 degrees from the level waterline. Inside the engine room , attach the string along the centerline of the shaft to the fro n t o f the eng ine room . If your string canno t stretch straight, you’ll need to redrill the hole cut in the bilge. Be care­ful no t to overbore this hole.

Make a cross-frame jig and attach it to the forward engine box wall or a bulkhead forward of where the engine is going to be m ounted. Adjust thejigs and the string until the shaft angle is correct and the stern bear­ing is in p roper relationship to the hull. (A Smartlevel is a real time-saver, electronically showing angles as held up to the string.)

Vernay Products Inc. o f Thomasville,

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Georgia, m anufactures an excellen t p re ­m ade fiberglass shaft tube. Made by a fila­m en t w inding process, these strong fiber­glass tubes can be easily b o n d ed in to a stitch-and-glue boat. After determ ining the appropriate tube size for your engine instal­lation, enlarge the hole in the bilge so you can slip the tube through the bottom of the boat a t the p ro p e r shaft angle. B ond the tube in place with high-density epoxy fillets, m aking sure the shaft is cen te red a t each en d and aligned with the string. O n a fin- keeled sailboat, y ou ’ll want the tube to extend slightly past the bottom o f the boat. Glass the in terio r and exterior with epoxy and several layers o f biaxial tape. I f your boat has a w ooden full keel, like the S urf Scoter, install the shaft tube by glassing w here it exits in to the inside o f the boat

only. T he outside o f the tube will ex tend th ro u g h the keel in a no tch cu tout. T he Surf Scoter calls for a tube of 2-inch outside diam eter and 114-inch inside diameter.

O nce the shaft tube has been glassed in place, the engine beds can be installed. For small diesel engines, the engine m ounts are usually parallel to the shaft, a lthough on certain m odels they may be as m uch as 1 inch above or below the shaft line. With X-inch plywood tem plate stock, m ake a p a tte rn fo r the eng ine m ounts. Then, taking careful m easurem ents o f the angle from the b o a t’s bottom , lam inate the engine beds from four layers o f high- quality J4-inch marine plywood. D epending on the shape of the hull and configuration of the m otor box, the bed may decrease in h e ig h t un til it runs ou t aft or, in some

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cases, ru n up to the cockpit longitudinals once clear o f the engine. T he Surf Scoter bed has a %-inch bridge at the top, extend­ing over to the sides o f the engine box and becom ing part of the cockpit longitudinal supports. This design allows several parts to serve double-duty and creates an extremely strong engine bed grid.

Sometimes, to avoid setting the flexi­ble engine m ounts directly on the wooden beds, I fabricate two slightly larger beds of stainless steel angle iron with nuts welded on th e bottom . T he eng ine m o u n t bolts will screw down into these nuts, thus hold­ing the engine securely onto the bed. The stainless steel beds fasten down over the inside edge o f th e w ooden eng ine beds,

and they allow you one m ore opportunity fo r ad justm en t to p ro p e r a lignm ent between the engine bed and shaft. If nec­essary, th e stainless steel beds can be shimmed before being bolted solidly to the wooden engine beds.

A nother helpful item toward a proper in b o ard installation is a flexible shaft log such as the type m ade by th e Buck- Algonquin Company. T he Surf Scoter uses an SL-125 FG fo r a lM-inch shaft. It looks like a b ronze packing box connected to a heavy, thick piece o f rad ia to r hose These packing boxes can be fastened to the end of the fiberglass stern tube with hose clamps, and are somewhat self-aligning because of the flexible nature o f the radiator hose.

Figure 26-2. A proper set of engine beds in the 29-foot Means o f Grace design. A horizontal f la t will be bonded, onto this bed port and starboard to complete the engine package. The whole area has received several coats of epoxy to seal it. Note the large round holes to access through-bolts on the engine mounts and to eliminate dead-air spaces.

1«5

La u n c h i n g

M uch like ch ildb irth , launch day mixes pain with joy. It m ight seem th a t this boat you've invested so m uch time and m oney on is unwilling to start its life off the cradle. My m ost vivid m ental im age o f a launch includes th e bu ild er chasing the boat down the ways with a p a in t b rush to get that last coat o f paint on the hull before it hits the water. No m atter how hard I try to get all the p re lau n ch jo b s done, a few always seem to slip through the cracks and pop up on launch day. At some point, the b u ilder m ust say: “No m ore paint! No m ore varnish! No m ore woodwork!” O ther­wise, even the smallest and simplest boat could be worked on forever. L aunch day usually occurs ju s t after my m ood has bot­tom ed ou t and is on its way up again. The corner is turned when I finally resolve not to do that extra work, bu t to shove the boat through the shop door. We’ve got a saying that goes, ‘You’ve got to hate ’em to finish ’em .” That is, you need some sort of moti­vation to finish the boat, and that motiva­tion may be a m om entary type o f loathing.

L aunch celebrations ru n the gam ut from large parties with h ired bands to low- key splashes with barely a few words o f ded­

ication. I like th e story ab o u t how some African boatbuilders used to launch their dugout canoes. The boatbuilder would not actually a tten d the launch , b u t instead would conceal h im self nearby, w ithin earshot. T h e re he would wait fo r the crow d’s response to th e launch. If he heard cries o f joy he would go and jo in the party, bu t if he heard groans and curses of sorrow and derision h e w ould bolt to a good h ead start on his angry pursuers, knowing th a t afte r a few weeks h e could re tu rn to less im passioned feelings, and start the next boat.

If you are going to have a formal party, launch th e boat twice, the first tim e as a dress rehearsal (a builder’s launch) without spectators. Crank the engines, rig the sails, and work through the boat’s systems. Satisfy yourself that everything’s in working order. T h e re ’s p lenty o f stress at a launch party; you d o n ’t n eed to add to it by having to troub leshoo t th e boat a t the last m inute. Then when you’re satisfied she is no t going to em barrass you, go th ro u g h th e form al launch— this o n e ’s fo r the owner now and you can give it the full attention it deserves.

Some peo p le w ant long dedications,

i e e

D e v l i n ’ s B o a t b u i l d i n g

o thers d o n ’t. My only consisten t rem ark for every boat is, “Over the land and into the drink, please God, d o n ’t let it sink!” It m ight be that I’ll say it ou t loud o r I might m u tte r it u n d e r my brea th . T he p o in t is,

the work ends only when the launch is suc­cessfully over, the b o a t’s tied up securely to a m ooring o r a dock, an d I’m back hom e with my feet up hoisting a few to the m em ories o f the others that preceded it.

167

1

R e p a i r s

Stitch-and-glue boats are remarkably tough and resilient. I have seen only one boat come back for a major repair in all my years o f boa t construction. It was a 22-foot Surf Scoter pow erboat, and I was aware o f the problem even before the owner called me.

T he winter o f 1990-91 was unusually tough in the Pacific Northwest, marked by m ore rain than anyone could rem em ber. In ju s t two days, we received over 16 inches, accompanied by several huge wind storms. O n one o f those evenings after work, I was w atching the news and saw a story ab o u t a m arina tha t was being assaulted by a particularly fierce no rth wind. The wave action was so intense that the m arin a ’s breakw ater was destroyed. Television cam eras p an n e d the watery chaos as boats were bounced about, some thrown onto the beach. People were trying to hold th e ir boats away from the rocks with their hands and feet. In the midst of this I noticed a flash o f green bouncing in and out o f sight, and recognized it as one o f my Surf Scoters.

The boatowner called a couple o f days la ter to re p o r t the whole story. His boat had been tied to the m ain stem of the dock

leading ou t from shore. Off the m ain dock were a n u m b er o f sm aller finger piers. W hen the breakwater started to fail, debris drifted dow n on the finger piers, which eventually broke away from the m ain trunk . All in all, approxim ately 30 boats were sunk, 30 were partially subm erged, and an o th e r 40 were pushed up on to the beach where the su rf took care of them.

O ur poor Surf Scoter rem ained tied to the m ain dock a long with e igh t o th e r boats. B roken cem en t docks with jagged edges and steel rebar projecting at water­line level floated down on to the boats, chewing into the Surf Scoter’s hull. A fish­ing boat had drifted into the S u rf Scoter and g ro u n d away at the topsides. T he resulting damage was a severely chafed and gouged stern , holes p u n ch ed in to the waterline on the p o rt side (thankfully the holes that penetrated went into the ballast water tanks), and a large hole through the p o rt topsides, ju s t above the galley, that looked like a new p o rth o le from the inside. T he stem was badly dam aged ju s t above the w aterline w here the boat had surged against the cem en t dock, chafing through a Xe-inch-thick, K-inch-wide brass

168

D e v l i n ’ s B o a t b u i l d i n g

Figure 28-2. The side o f tlw same boat. The gillnet fishing boat that did this damage ulti­mately sank in the storm.

Figure 28-1. The stem o f a toitured Surf Scoter after a big Puget Sound storm in 1990. Many of this boat’s neighbors were sunk during the same storm.

half-oval on the stem an d a 2-inch by 6- inch timber chafe strip on the dock.

T he day after th e storm , the ow ner’s wife ran the boat 10 miles across a bay to the nearest h au lo u t facility. A couple o f weeks later I looked the boat over to make an estim ate o f the rep a ir costs, and n o t long afterward towed the boat back to my shop for repairs.

It was a great opportunity to open up a boat to see how it was holding up. T he Surf Scoter was about four years old at the time o f repair, and I could find no evidence of discoloration in the wood to indicate mois­ture invasion; best o f all, the epoxy sealing on both sides o f the hull panels looked as good as new.

T he stem was the easiest to repair. We cu t away the dam aged m ateria l down to good wood, an d th en shaped a wood d u tch m an to fill the cu tout, glu ing it in place with epoxy.

T urn ing to the new port-side “p o rt­

ho le ,” I cut o u t th e dam aged area with a ro u te r to en large the hole in to sound, undam aged wood, then routed the perime­ter about halfway through the K-irich-thick hull side, creating a “s tep p ed ” opening. Two %-inch plywood patches were cut: one to fit in to the hole, and a second, slightly larger one to fit in to the ro u ted shelf a round the hole. I glued the largest in first, fastening th rough th e narrow flange a ro u n d th e hole. ^Vfter th e glue dried , I glued and fastened the smaller patch into place, b ring ing th e rep a ir flush with the h u ll’s in te rio r and ex te rio r surfaces. To h ide the rep a ir in th e varnished in te rio r surface, I cu t a long butt-block pane l to cover it. T he galley co u n te rto p was re in ­stalled in its original position, and with the b u tt block in place, the patch looked like part of the original construction.

O n the exterior, the rep a ir an d sur­ro u n d in g p a in ted area o f the hull were sanded until the glass cloth layers were vis­

169

R e p a i r s

ible. T he patch was g ro u n d to Ke-inch below the surrounding surface level o f the original hull. Two pieces o f 6-ounce fiber­glass cloth, one coveringjust the patch and the o th e r cu t la rg er to overlap th e hull 6 inches on all sides o f the patch, were lami­na ted in p lace with epoxy an d peel ply. A light sand ing and a coat o f m icrobal­loon /epoxy fairing com pound leveled the rep a ir surfaces. To save a little tim e and effort, I covered th e fa iring co m pound with 2-inch-wide clear cellophane packing tape, th en sm oothed th e tape with a squeegee. W hen th e tape was la te r rem oved it revealed an extrem ely sm ooth patch. (The tape also holds the filler m ate­rial firmly in place on vertical surfaces, pre ­venting sags.) All th a t rem ained was to prim e and paint the repair. The Surf Scoter was repaired with about 90 hours o f labor, m ost o f which was taken u p in the com ­plete stem-to-stern ex terio r rep a in ting of the boat. T he patches were easy to do and involved no m ore skill than any o ther part o f the stitch-and-glue construction process.

I am periodically asked about design­ing a boat fo r ex ten d ed cruising in cold, hostile waters. This type o f cruising intrigues me. I have always been drawn to

rem ote and desolate places, and my efforts in designing include m aterials th a t will fare well in extrem e conditions.

Steel is resilient, alum inum allows free­dom from p a in t an d co n cern for co rro ­sion, and fiberglass is strong. But, welding patches o f steel does n o t appeal to m e, I detest the cold gray color o f unpainted alu­m inum , an d I c a n ’t see carrying a TIG w elder with me to facilitate patches. A fiberglass boat would need to be epoxied if damaged, and its interior would need to be covered with wood o r fabric ceiling to avoid co ndensa tion problem s in a cold environm ent.

I believe th e w ooden stitch-and-glue boat is the best answer. A wood boat doesn’t sweat, so you could have a hull in which all in te rio r surfaces were visible an d easily accessible. In the event o f hu ll dam age, p recu t plywood patches with w ate rp roo f po lyu rethane caulking a t th e edges and som e bronze ring-shanked b o a t nails o r screws are all you’d need to quickly fasten a temporary patch over most any hole. And with w ood’s relatively light-weight-to-high- strength ratio, a stitch-and-glue hull would rate better than most at being a good ship­mate in extrem e conditions.

170

De v l i n ’s De s i g n s

H ere is a sam pling o f designs available from the Devlin shop. A 100-page catalog detailing 43 stitch-and-glue designs is avail­able for $10 by writing o r calling:

Devlin Designing Boat Builders 2424 Gravelly Beach Loop, N.W. Olympia, WA 98520 (360) 866-0164, FAX (360) 866-4548

C A C K L E R

171

D e v l i n ’ s D e s i g n s

P O L L I W O G

Pollywog Materials List

2 sheets 4 x 8-foot, K-inch plyood12 feet mahogany, 1 x 1 2 inches1 gallon epoxy resinlA gallon epoxy h ardener1 roll (50 yards) 4-inch x 8-ounce

fiberglass cloth7 yards 38-inch x 6-ounce

fiberglass cloth2 pounds wood flour2 quarts prim er1 pint varnish1 quart enam el2 #4482 Wilcox C rittendon

oarlock sockets

POLLIWOG

L.O.A. 7 '6 ”

BEAM 4'1 "

WEIGHT 59 LBS,

172

D e v l i n ' s D e s i g n s

S E A S W I F T

174

175

D e v l i n ’ s D e s i g n s

NANCY’S CHINA DC

NANCY5SCHINA DC

li.O.A. 15 '2 "

BEAM 6'2 "

DRAFT (FP) L O "(DOWN) 2'iJ "

SAIJL 124 SQ.AREA FEET

176

D e v l i n ’ s B o a t b u i l d i n g

D e v l i n ’ s D e s i g n s

178

D e v l i n ’ s B o a t b u i l d i n g

N O D D Y

NODDY

L.O.A. L5 '1 1 "

BEAM 7 ' l O "

DRAFT L3"

179

D e v l i n ' s D e s i g n s

DIPPER

DIPPER

Ti.O.A. 1 6 '4 "

BEAM 7 '

DRAFT 1 >K "

DISPLACEMENT1300 LBS.

ISO

D e v l i n ’ s B o a t b u i l d i n g

M IliL IE H l l i l i

MILLIE HILL

Ij.O.A. 2 0 '0 "

D.W.Tj. 1 7 '5 "

BJEAM 8 f2 ”

DRAFT 12"

181

D e v l i n ’ s D e s i g n s

SURF SCOTER

S l 'E F SCOTER

IEN G TH 22 '0"

D.W.Ii. 20'3 "

BEAM 7'H"

DRAFT I ' l l "

182

D e v l i n ’ s B o a t b u i l d i n g

B L A C K C R O W N 2 9 '

BLACK CROWN 2 9 '

LENGTH 2 9 '2 ' '

BEAM lO '

DRAFT 2 '3 "

DISPLACEMENT8400 LBS.

183

D e v l i n ’ s D e s i g n s

CZAI.’I N X A 3 0 '

fZAEINNA 30

D.O.A. 2 » '1 0 "

D.W.D. 2 5 '3 "

BEAM 8'6 "

DRAFT 2 '4 "

DISPLACEMENT

890 0 DBS.

184

D e v l i n ’ s B o a t b u i l d i n g

BLUE PETEK

B L U E PETER

Li. O.D. 3 0 ' 2 "

L.W .L. 2 4 ’H "

BEAM 9 '3 "

DRAFT l '7 "

185

D e v l i n ’ s D e s i g n s

OYSTA 42'

OYSTA 4 2 '

LENGTH 12 '1 "

BKAM 1 2 '1 "

DRAFT 5 'O "

Ii.W.Ii. 3 7 '0 ”

DISPLAC24

EMENT ,000 LBS.

IiiST o f S u p p l i e r s

T he following is n o t a com plete list, b u t I believe all the suppliers listed to be reliable and dependable. Specialty m arine, lumber, and tool com panies often change hands or go o u t o f business, and new ones are form ed ju s t as often. I include this list in th e h o p e it will be helpfu l. Please d o n ’t ho ld m e responsib le fo r th e pace o f change in the 1990s. Finally, an im portant source for me in com piling this list was Bob Stew ard’s Boatbuilding M anual, F ourth Edition (IM, 1994). Thanks to Bob and his excellent book.

Boatbuilding Plans

Many o f th e designers listed below offer brochures, catalogs, o r both.

B.C.A./Demco Kit. 505 Via Riccarelli, 21-20148, Milano, Italy.

Ted Brewer Yacht Designs, Box 187, Lyman, WA 98263.

Com plete Guide to Boat Kits & Plans, P.O. Box 540638, M erritt Island, FL 32954.

Devlin Designing Boatbuilders, 2424 Gravelly Beach Loop N.W., Olympia, WA 98502.

Glen-L M arine Designs, 9152 Rosecrans, Bellflower, CA 90706.

H ankinson Associates, P.O. Box 272, Hayden Lake, ID 83835.

IBIS Boatworks (Alan C hin), P.O. Box 65, Glen Huntly, VIC 3163, Australia

Norwalk Island Sharpies, 213 Rowayton Avenue, Rowayton, CT 06853.

H. H. (“Dynamite”) Payson & Company, Pleasant Beach Road, South Thom aston, ME 04858.

Pygmy Kayaks, Jackson Street, Port Townsend, WA 98368.

Databoat In tern a t’l Ltd., Box 1073,8609 Fis­sile Lane, Whistler, B.C., Canada VON 1B0.

Island Boat Plans, 40 Belle Vue Rd.,Cowes, Isle o f Wight, P031 7HJ, England.

Tools and Hardware

Adjustable Clamp Company, 417 N. Ashland, Chicago, IL 60622. Complete line of clamps under the “Jorgensen” and “Pony ” brand names.

Cascade Tools, Inc., P.O. Box 3110, Bellingham, WA 98227. Router bits and drill bits.

Albert Constantine & Sons, Inc., 2050 Eastchester Rd., Bronx, NY 10461, and C onstantine’s Wood Center, 1040 O akland Park Boulevard, Ft.Lauderdale, FL 33334. Distributors of tools, in cluding taper-point drills for wood- screw holes and Japanese hand saws, chis­els, planes, and waterstones; also carries finishing materials, interior joinerwork hardware, and abrasives.

187

L i s t u f S u p p l i e r s

Fein Power Tools, Inc., 5019 W. Carson Street, Pittsburgh, PA 15204.

W.L. Fuller, Inc., 7 Cypress Street, Warwick, RI 02888. Countersinks, counterbores, plug cutters, tapered drills.

Garrett Wade Company, Inc., 161 Avenue o f the Americas, New York,NY 10013. Hardware and tools, includ­ing a large variety of Japanese hand tools.

Gougeon Brothers, Inc., 706 Martin Street, Bay City, MI 48706. An epoxy­supply firm that also sells the Scarffer, an attachment for a portable circular saw.

H ighland Hardware, 1045 N. Highland Avenue N.E., Atlanta, GA 30306. Wide selection of woodworking tools (power and hand).

John H enry Inc., P.O. Box 473, Spanish Fort, AL 36527. The John Henry Planer- Scarffer A ttachment.

Wetzler Clamp Company, Rte. 611, Box 175, Mt. Bethel, PA 18343. Complete line of clamps.

Wilcox-Crittenden, Middletown, CT 06457. Complete line of marine hardware, including navigation lights.

Wood Carver’s Supply, P.O. Box 8928, Norfolk, VA 23508. Cutting tools.

Woodcraft, 210 Wood County Industrial Park, Parkersburg, WV 26102-1686. Japanese chisels, hand saws, waterstones, and slipstones.

Boat Equipment Chandlers

Doc Freem an’s, P.O. Box 300314,Seattle, WA 98103.

Fisheries Supply, 1900 N. Northlake Way, Seattle, WA 98103.

West Marine, 500 Westridge Drive, Watsonville, CA 95076.

Sails

C enter H arbor Sails, Brooklin, ME 04616.Lidgard Sails, 3507 Evanston Avenue N.,

Seatde, WA 98103.Port Townsend Sails, 315 Jackson Street,

Port Townsend, WA 98368.

Bronze Marine Hardware

ABI Industries, 415 Tamal Plaza, Corte Madera. CA 94925.

Bristol Bronze, P.O. Box 101, Bristol, Rl 02878. Specializes in reproductions of Herreshoff Manufacturing Company hardware.

Bronze Star, Inc., 1235 Scott Street, San Diego, CA 92106.

Buck-Algonquin, 1565 Palmyra Bridge Road, Pennsauken, NJ 08110.

Marine Associates, 1651 Hanley Rd., Hudson, WI 54018. Single-arm and V-propeller shaft stmts, rudder ports, tiller arms, shaft logs, and stuffing boxes.

New Found Metals, Inc., 240 West Air­port Road, Port Townsend, WA 98368.

Port Townsend Foundry, 11 Crutcher Road, Port Townsend, WA 98368.

Simpson Lawrence USA, Inc., Box 11210, Bradenton, FL 34282-210. Windlasses, CQR “plow ” anchors, and other products made m Scotland.

Spartan Marine, Hardware Division, Robinhood M arine Center, Robinhood, ME 04530. Bronze and stainless steel hardware.

Lumber, Plywood

Black M ountain Wood Company, P.O. Box 130, South W indham, ME 04082.Hardwoods and pine; manufacturer of wood components.

188

D e v l i n ’ s B o a t b u i l d i n g

Boulter Plywood Corporation, 24 Broadway, Somerville, MA 02145. Douglas fir, quarter-sawn or sliced teak and okoume marine plywood to British standards. Also solid lumber: teak, ash, Honduras mahogany, white oak, khaya, and premium vertical-grain Sitka spruce spar stock.

M. L. Condon Company, Inc., 258 Ferris Avenue, White Plains, NY 10603.Mast- and spar-grade Sitka spruce, Philippine and Honduras mahogany, white cedar, oak, teak, cypress, Alaska yel­low cedar, Douglas fir, and lignum vitae; fir, teak, ash, mahogany, and imported Bruynzeel mahogany plywood.

Albert Constantine & Sons, Inc., 2050 Eastchester Rd., Bronx, NY 10461.Sells a meter for determining the moisture content of wood.

Dean Company, P.O. Box 426, Gresham, OR 97030. 'A"-thick veneer for cold- molded plankings.

Edensaw Woods Ltd., 211 Seton Road, Port Townsend, WA 98368. Teak, iron- bark, mahoganies, Douglas fir, Alaska yel­low cedar, and Western red cedar. Also Kel- brand marine plywood, to British standard 1088. Okoume or sapele faces with okoume core throughout; each panel subject to ultra­sonic testing for ply lamination.

Flounder Bay Boat Lumber, T hird and O Streets, Anacortes, WA 98221;(206) 293-2369. Marine plywood, dimen­sional boatbuilding lumber.

H arbor Sales Company, 1400 Russell Street, Baltimore, MD 21230. Teak, okoume, sapele, fir, lauan, waterproof plywood.

Horsepower Logging Company (Tom H am ilton), RFD 1, Box 192,Cornville, ME 04976.

H udson Marine Panels, Box 58, Ashley,

PA 18706; Box 1184, Elkhart, IN 46515.Lucky G. Farms, Box 5920, Hartland,

ME 04943. Hackmatack kneesNorthwoods Canoe Shop, RFD 3, Box

118-2A, Dover-Foxcroft, ME 04426. Canoe-building material including white cedar; also a VHS video made in their shop that covers wood bending selection and preparation of wood, and construc­tion of a steam box.

Olyve Hardwoods, Wilmington, NC; (919) 686-4611. Teak, marine plywood, mahogany, Atlantic white cedar; no minimum.

Fred Tebb and Sons, Inc., 1906 Marc Street, Tacoma, WA 98421. Sitka spruce specialists: wet or dry, rough or planed, various grades.

West Wind Hardwoods, Inc., Box 2205, 10230 Bowerbank Road, Sidney, B.C. Canada V8L 358; (604) 656-0848. Bruynzeel and domestic marine plywoods, Sitka spruce, fir, red and yellow cedar; dis­tributor for Harbor Sales Company.

Wooden Boat Shop, Seatde, WA; (206) 634-3600. Marine plywood

Fiberglass

Defender Industries, Inc., 255 Main Street, P.O. Box 820, New Rochelle, NY 10802-6544.

Erskine Johns, 4677 Worth Street, Los Angeles, CA 90063.

Metal and Plastic Fasteners

Chesapeake Marine Fasteners, P.O. Box 6521, Annapolis, MD 21401.

C opper Nail, P.O. Box 936, Sacramento, CA 95804. Copper clench nails.

Hamilton Marine, Route 1, Searsport, ME 04974.

189

L i s t o f S u p p l i e r s

Independen t Nail Inc., Bridgewater, MA 02324. Makers o f Anchorfcist nails.

Jamestown Distributors, P.O. Box 348, Jamestown, RI 02835 and Rt. 1, Box 375, Seabrook, SC 29940. A ll types of marine fasteners.

Pacific Fasteners U.S., Inc., 2407 South 200th Street, P.O. Box 58304, Seattle, WA 98188. Flathead silicon bronze wood screws with square socket heads in sizes ranging from #6 x 3A" to #14 x 3" long.

Epoxy

Gougeon Brothers, Inc., P.O. Box 908,Bay City, MI 48707.

Industrial Formulators o f Canada, Ltd., 3824 William Street, Burnaby, B.C., Canada. G2 and Cold Cure epoxies.

SP Systems, Blake’s Marine Paints Ltd., Har­bour Rd., Gosport, Hampshire, P012 1 BQ.

Hankinson Associates, P.O. Box 272, Hayden Lake, ID 83835.

Matrix Adhesive Systems, 1501 Sherman Avenue, Pennsauken, NJ 08110. High- tech epoxies for boatbuilding.

System Three Resins, P.O. Box 70436, Seattle, WA 98107.

Deck and Companionway H atches

Bomar, Inc., Box W, Charlestown, NH 03603.

Go Industries, 20331 Lake Forest Drive, U nit Cl 4, El Toro, CA 92630.

Taco Supply, 1495 N.E. 129th Street,N orth Miami, FL 33161 and 18870 72nd Avenue South, Kent, WA 98032.

Windows

American Marine, 1790 SW 13th Court, Pom pano Beach, FL 33069.

B & J Aluminum Windows, Route 5, Box 4812, St. Martinville, LA 70582.Heavy-duty metal windows.

Noncorrosive Locks

Phoenix Lock Company, 321 Third Avenue, Newark, NJ 07107-2392.

Abrasives

Albert Constantine & Sons, Inc., 2050 Eastchester Rd., Bronx, NY 10461.

T he Sanding Catalog, P.O. Box 3737, Hickory, NC 28603-3737.

O ne-O ff or Production Castings o f Lead

Mars Metal, 4130 Morris Drive,Burlington, ON, Canada L7L 5L6.

Willard, 101 New Bern Street, Charlotte, NC 28203.

Aluminum Alloy Spars

Dwyer Aluminum Mast Company, 21 Com merce Drive, N orth Branford, CT 06471.

Hall Rigging, 17 Peckham Drive, Bristol, R I02829.

Kenyon Marine, New Whitfield Street, Guilford, CT 06437.

Taco Supply, 1495 N.E. 129th Street, N orth Miami, FL 33161, and 18870 72nd Avenue South, Kent, WA 98032.

Spar Tech Co., 5230 N.E. 92nd Street, Redmond, WA 98052-3518

W ooden Yacht Blocks

Bainbridge Blocks, 1481 Shoemakers- ville Rd., Shoemakersville, PA 19555.

190

D e v l i n ’ s B o a t b u i l d i n g

Finished ash shell blocks; also kits for do-it- yourself finishing and assembly.

Pert Lowell Company, Inc., L ane’s End, Newbury, MA 01951.

Hydraulic Steering Com ponents

Hynautic, Inc., 1579 Barber Road, Sarasota, FL 34240.

Teleflex, Inc., 640 N orth Lewis Road, Limerick, PA 19468.

W agner Marine (USA) Inc., 14326102nd Street N.E., Bothell, WA 98011.

Engine Controls

Edson International, 460 Industrial Park Road, New Bedford, MA 02745-1292. Control heads.

Kobell M anufacturing Company, Ltd., 11720 Horseshoe Way, Richmond,BC, Canada V7A 4V5. Control heads.

Morse Controls, 21 Clinton Street, H udson, O H 44236. Control heads; push-full cables.

Teleflex, Inc., 640 N orth Lewis Road, Limerick, PA 19468. Push-full cables.

Circuit Breaker Panels

Heritage Panel Graphics, 5710 200th Street SW, #307, Lynnwood, WA 98036-6257.

Marinetics Corporation, P.O. Box 2676, Newport Beach, CA 92663.

Oars, Paddles, Oarlocks

Barkley Sound Marine, 3073 Vanhorne Road, Qualicum Beach, BC, Canada V9K 1X3.

Shaw & Tenney, 20 Water Street, P.O. Box 213, O rono, ME 04473.

T he W oodenBoat Store, P.O. Box 78, Brooklin, ME 04616. Plans for making oars, as well as a leather-and-button kit ivith instructions and enough leather and fasteners for one pair of oars.

Steering

Edson International, 460 Industrial Park Road, New Bedford, MA 02745-1292.

Water Trap Vent

Nicro Marine, 2065 West Avenue 140th, San Leandro, CA 94577.

Tanks

Tempo Products Company, P.O. Box 39126, Cleveland, O H 44139. Stock metal and nonmetallic tanks.

Vetus Den O uden, Inc., P.O. Box 8712, Baltimore, MD 21240-0712. Stock nonmetallic tanks.

Computer Lofting Services

Aerohydro, Inc., P.O. Box 684, Main Street, Southwest Harbor, ME 04679.

Vacanti Yacht Design Software, 17226 163rd Place SE, Renton, WA 98058.

Specialty M arine Contractors, P.O. Box 1081, Scappoose, OR 97056.

Respirators

3M Occupational H ealth & Safety Products Division, 1-800-328-1300.Extensive line of respirators.

Safety Inform ation

U.S. Coast Guard, Office o f Boating Safety, Washington, DC 20590.

191

I n d e x

Note: Boldface type indicates illustration.

access holes (pigeon holes),144, 146

adhesives,polysulfide/polyurethane, 27-28, 142, 147-148, 159, 160, 162

Sikaflex, 27, 159 3M 5200, 27, 159

air bubblesin epoxy, 36,43,110,112-113,

116 air voids

in plywood, 21-22, 23 between layers o f plywood

(cold m olding), 124-125 Alaskan yellow cedar, 28 alum inum extrusion:

Taco Metals A52-0037, 149 angle gauge, 99 antifouling paint, 137,

138-139 Arctic Tern, 76, 155, 163

ballast, 142-143 for scale m odel, 68 suppliers, 190

balsa: m odeling techniques, 57-58

balsa-core, 72bandsaw, 11-12; Powermatic,

11-12 barrier cream, 158 battens

loflinp/drafting, 18, 53-54, 62-64, 68

as spreaders, 86-87

for verifying bulkhead placem ent, 97

battery: used for softening cured epoxy, 121-122

beambeam /crow n, 103 half-beam marks, 62-64, 99 m easuring/verifying, 94—99 sheer spreaders, 68-69,

94-95, 105 bedding com pound:

polysulfide/polyurethane adhesives, 27-28, 147, 159,

160, 162 belt sander, disc, 18, 48 berth flats, 42, 72, 144-146 bevel gauge, 17 bevels/beveling

of panel edges, m odel, 65-66 o f panel edges, full-size

boat, 84-85, 87, 91 for scarf jo in ts, 46-47

bilgeaccess to, 142construction considerations,

99, 106 foam-filled, 142-143 joints/scantlings, 77-78 ventilation of, 142-143

Black Crown, 5, 95, 125 block and tackle, 120 block plane, low-angle: Stanley

118, 10 blocks, wooden: suppliers,

190-191 Bolger, Phil 79 bottom , painting, 137,

138-139 bottom spreaders, 86-87

bow: transition jo in t (chine), 87-90

breasthook: wood for, 23 Brewer, Ted: Cape Cod 22

Catboat adaptation, 55-56, 58-59, 60-64, 73

building m olds/tooling , 1, 5 bulkheads as (tack-and-tape

construction), 79 bulkheads, as integral fram ­

ing /m olds, 79 bulkheads, structural, 70-73,

92-93 access/cutouts in, 144 angled, 99 athwartship, 42, 144 double, 101 installation, 93-102 locating/verifying, 52,

93-99 longitudinal, 143-144 scantlings for, 72-73 scribing, 15, 99-100 seam s/bonding, 100

bungs, 145-146, 160 bu tt joints: in cold m olding

(additional plywood lay­ers), 124

cabin, in terior structure construction/installation,

141-149 finishes for, 44, 152, 159

cabinsides, 42 cabin sole, 72, 141-143 cabintop, 42, 72

cam ber/crow n, 102 scantlings fo r beams, 74—75

Cabosil, 37, 38, 49, 110, 156

192

D e v l i n ’ s B o a t b u i l d i n g

CAD (computer-assisted design) systems, 59

lofting services, 191 cam ber (crown)

o f deck/cabin top , 102-103 jigs, 103 ruler, 102-103

Cape Cod Catboat: adaptation o f Ted Brewer design, 55-56, 58-59, 60-64, 73

caprails, 160 carbon-fiber cloth, 44 caulking: polyurethane adhe­

sive, 142, 147 See also adhesives, polvsul-

fide/po lyure thane centerboard, 127-129 Cetol teak finish (Sikkens

Com pany), 27, 160 chalkline, 15, 17 cheek blocks: wood for, 23 chine

beveling panel edges at, 87, 91

jo in ts/scantlings, 42, 75, 77 m ultichined boats, 95, 97,

105overlapping o f panels at,

83-84, 91 transition jo in t (approach­

ing bow ), 87-90 ch ine/half-chine p lane/lift,

60-66circuit breaker panels: suppli­

ers, 191 circular saw

scarfing jig for, 46-47 Skilsaw (wormdrive), 11

clamping: scarfjoints, 49-50 clear coat. See epoxy

sealer/coating; varnish cleats, wood: wood for, 27 Coast Yacht Design, 59 cockpit: bulkheads in, 143-144 cockpit sole, 72, 142-144, 143 cold m olding, 1, 44

additional plywood layers over siitch-and-glue hull, 123-126

com pass/dividers, 15, 17, 62 com puter assisted design

CAD systems, 59

com puter lofdng services, 191

cored hull materials, 72 countertop lam inate

for m odeling, 66 for sheathing cen te rb o a rd /

daggerboard trunk, 127 cradle, 79-81

how to build, 81-82 leveling, 80

cyanoacrylate (CA) glue, 64-65, 146

accelerators, 65 debonder, 65

Czarinna, 57, 59, 73

daggerboard trunk, 127-129, 142

deck beams, 74-75 cam ber of, 102-103 lam inated, 75 wood for, 23

decks, 72, 104crow n/cam ber, 102-103 lam inated, 75 wood for, 27

designadapting to stitch-and-glue,

55-56, 58-59, 60-64, 73 CAD (computer-assisted

design) systems, 59 chine p lane/lift, 60-66 half-beam marks, 62-64 intuitive, 57-58 m odeling techniques for,

55-69 profile, 60-66 refinem ents/innovations,

1 -2 ,5 selecting, 19-20 sheer p lane/lift, 60-66 transferring from p la n /p a t­

tern to stock, 62-64 transom plane/lift, 60-66 See also lofting; plans

designs by Sam Devlin,171-186. See also Arctic Tern, Cape Cod Catboat, Czarinna, Egret, H ope of Glory, Means o f Grace, Nancy’s China, Oarling, Oysta 42, Peeper,

Polliwog, Solo Canoe, S urf Scoter, W inter Wren

dim ension m arks/points, 52-54

disc sander, 18operation of, 134-136

displacement. See weight, displacem ent

doorscabinet, 146, 147-149 companionway, 149

dories, coastal, 20 Douglas fir, 24, 25, 28, 106 drift boats, McKenzie River, 20 drill, cordless: Panasonic

EY6205BC, 18 drill bits

brad-point, 12, 146 index, 12, 17

drillingair-escape holes (plywood

cold-m olding), 124 for wire stitches, 84, 88-89

drill press, 146 Delta 11-990, 18

drills: Milwaukee Magnum Holeshooter, 12, 17

drop slides/boards, 149 dust mask. See respirators dust-removal systems: Fein

Power Tools, 136 Dynel, 44, 130

Egret, 73engine beds, 72, 163-165 engine box, 99 engine (inboard) installation

design/construction consid­erations, 139, 143-144

shaft log, 164—165 shaft/ste rn tube, 139, 164,

165engine controls: suppliers, 191 epoxy, 2, 4, 6, 29

air bubbles in, 36, 43, 110, 112-113, 116

cautions/hazards, 30, 32, 33-35

cleaners/solvents, 17, 34, 36 cleanup, 32-33, 34, 36-37 clim ate/w eather and, 30,

35, 156

193

I n d e x

cured, softening, 121 curing, 8, 30, 34, 36, 155 flashing (overheating), 30 hardeners/form ulations,

30, 32, 34, 35, 42 heat dam age, 42-44,

154-156 m ixing/m easuring, 30-33,

35-36 post-curing, 156, 157

protective gear, 17, 32, 33-36, 114

sanding, 34secondary bonding, 29, 112 sensitization (allergic reac­

tion), 33-34 suppliers, 190 storage, 35-36 systems, 30-32, 35, 43-44 tem perature and, 32, 35,

42-44tips for working with, 35-37 tools/m ixing parapherna­

lia, 17, 31-33, 35-36 UV dam age/pro tection , 154

washing cured surface (before sanding), 132,136

epoxy d ispensers/pum ps, 17, 32

cleaning, 32—33, 34 epoxy/fiberglass sheathing

See fiberglass/epoxy sheath­ing

epoxy fillers/filleting mix­tures, 29, 37-38, 109-111

air bubbles in, 110,112-113, 116, 136

Cabosil, 37, 38, 49, 110, 156 microballoons, 37, 38, 136,

156, 157 M icrolight fairing com­

pound (West System 410), 38, 157

m icrospheres, 37 repairs/gouges, 136 sanding, 136 for stitch holes, 12 wood flour, 37, 38, 49,

109-111, 136 epoxy g lues/g lu ing tech­

niques, 29 clam ping/weights, 49-50

preparation o f wood for, 27,28

scarfing, 47-50 epoxy paint, 150-151, 157 epoxy primer, 138, 150-151,

153-154, 157 Ditzler DP 40, 138, 150-151,

153-154, 157 PPG K36 Prima, 157

epoxy sealer/coating , 25-26,28, 36, 132, 136, 156, 157

air bubbles in, 36for hardware, 162 lim itations o f in re thickness

o f wood, 77-78 and plywood longevity, 23 sealing in terior surfaces,

100, 127, 142, 143 staining and, 28, 29 UV protection of, 154 wire stitches/fasteners and,

121, 126

fasteners, m etal/m echanical bungs for, 145-146 and epoxy sheathing, 56 for hardware, f 62 for in terio r woodwork, 28 for keel jo in t, 127-128 used in plywood cold m old­

ing, 125-126 used in scarf joints, 49-50 suppliers, 189-f90

fiberglass boats, 1, 5 fiberglass cloth

alternatives to, 44 for exterior hull sheathing,

130overlapping, 132-133, 156 sanding cautions, 134, 157 suppliers, 189 types of, 39-40 woven vs. knitted (biaxial),

40fiberglass/epoxy sheathing,

29, 39, 156air bubbles in, 43 o f cen terboard /dagger­

board trunk, f27 finishes for, 44 o f hull exterior, 4 f-42 , f29 of interior, 44

m etal fasteners and, 56 and plywood longevity, 23 print-through (telegraph­

ing), 42-44, 155-f56 reinforcem ent, 4f sanding and fairing, 39,

f32, 134-136, 156 fiberglass tape

biaxial vs. woven, 76-77 precu tting your own, 15,

40-41, 77, 111-116 prem ade, 41seam /jo in t scantlings, 75-77 See also seam taping

fiddles, 144-146; wood for, 27, f45

fillers. Seeepoxyfillers/filleting mixtures

fillets (covedjoints), structural,29

scantlings, 75-77 wood flour filleting m ixture,

37, 109-111, 115 See also tabs, seam

fillets, nonstructural, 1 1 4 -fl5 fir: dom estic plywood, 21-22,

72. See also Douglas fir floor tim bers

layout/installation, 106-108, 141-143

wood for, 28 floorboards: wood for, 27 foam, polyurethane, 142—143 Formica. See countertop

lam inate frames: wood for, 28 freeboard, 94

glassing box, 33, 113-116 glazing putty, 157 gloves, 17, 32, 33-36, 158 glues/g lu ing techniques. See

epoxy g lues/g lu ing tech­niques

G ougeon Brothers, 36 Scarffer 875, 46-47

guards. See sheer guards gunwales, 23, 70

bending, 25 wood for, 23, 25, 28

gunwale sheer clamp,104-105

194

D e v l i n ’ s B o a t b u i l d i n g

half-beam marks, 62—64 ham m ers, 12-13, 17

cleaning, 36 Vaughan, 13

handrails, 161 wood for, 27

handsaw, 17 hardware, 162

backing plates for, 162 sources, 187-188

hatches, 147-148carlin system, 149 slides, 149

hea t gun, 132-133 heaters, workshop: 30, 156 Henry, John : scarfing attach­

m ent, 47 H onduras mahogany, 27, 28,

106H ope of Glory, 73hose: for water level, 96, 137hull

leveling, 93-99, 137, 141 repairs/patch ing , 169-170 righting, 140 rollover, 100-101, 105,

117-120 sheathing, 41-42, 129,

130-133 skin thickness/scantlings,

73, 123, 126 hull, color of. See paint, f in ish /

topsides hull, size o f

and cradle scantlings, 82 and hull jo in t scantlings, 77

hull panels, shapes of conversions, 61—64, 68 lofting, 51-54 m odeling techniques for

developing/ designing, 57-67

projecting (from half­m odel) on to Mylar, 67-68

hull seam s/joints, 93 beveling panel edges at,

84-85, 87, 91 chine, 42, 75, 77, 83-84,

87-91 filleting and glassing,

109-116 hull-to-deck jo in t, 104-106

keel jo in t, 84-86, 128-129 layering of fiberglass tape, 41 scantlings for, 75-77 stem, 128-129 tabs for stiffening, 96, 108,

112, 121 transition (bow /chine),

87-90hull-to-deckjoint: reinforced

by sheer clamp, 104—106 hull twist, longitudinal: causes/

prevention, 80, 96,112

inlays, glued: in hatch cover, 147

in terior surfaces epoxy-sheathing, 44 finishes for, 152 pre-painting, 159

ironbark worm shoe, 127

jackstands (boatstands),79-80, 95

jigsaw: Bosch 1581, 11, 17 jitterbug . See sander, vibrating jo in ter, 18 jo in ts

bu tt jo in ts, 124 scarfjoints, 45-50 taped and filleted, 75-77.

See also hull seam s/joints

keel, 127-129accom m odation o f in cradle

construction, 81-82 joint, scantlings/construc­

tion, 77-78,128-129 lam inated, 78 line of, stitching panels

along, 86 solid, 128 wood for, 23, 25

Kevlar, 44, 130 khaya, 22, 27 knife, rigging, 13-14 knife, utility, 15. 18

lam inated w ood/plywood decks/cabintop, 75 sheer clamp, 70-71, 73-75,

105, 108 keel, 78

lauan (Philippine) mahogany, 27

launching, 166-167 cradle for, 79-80

leveling cradle, 80floor timbers, 107-108 hull, 93-99, 137, 141

levels, 15 Smardevel, 15, 17, 96, 99 spirit, 99, 107 water (hose) level, 96, 137

Lexan: hatch top, 147-148 Lichen, 58, 104-105 Lichen, 58, 104-105 lim ber ho les/lim bering

bulkheads, 99 locks: suppliers, 190 locust, 160-161 lofting, 51-54, 68

battens for, 18, 53-54 com puter lofting services.

191dim ension points/m arks,

52-54proofing/verifying bulk­

heads, 52, 94-99 station marks, 52-53, 62

lumber, dimensional air- vs. kiln-dried, 24, 26 bending, 25-26 defects, 25-27 for fiddles, 145 grains, 24-2hardw ood vs. softwood, 24 rot, 28 scarfing, 47 selecting, 23-28 species/types, 25-28

suppliers, 188-189 tw isting/grain runout,

25-26 wind shakes, 27

mahoganydim ensional lumber, 26-27,

145, 160-161 plywood, 22, 72

m asts/sparsalum inum alloy, suppliers,

190wood for, 23, 25-26, 28

195

I n d e x

mast step: building/installing, 141-142

materials, cost of, 19 Means of Grace, 7, 72, 80, 124,

139, 145, 146, 165 m eranti (lauan m ahogany), 27 metal fasteners. See fasteners,

m etal/m echanical m icroballoons, 37, 38, 136,

156, 157 M icrolight fairing com pound

(West System 410), 38,157 m icrospheres, 37 m ixing cups, 17 m odeling techniques

balsa/intuitive, 57-58 flotation m odel/tank-test­

ing, 68-69 glues for, 64-65 half-models, carved, 58-59 half-models, paneled, 59-67

scale, 61 tools for, 65 wood for, 58, 62, 65-66

molds. See building m olds/ tooling

m otor well, 143-144 m ultichined boats, 95, 97, 107 Mylar, 67-68

Nancy’s China, 3, 73, 75, 142,146-147

non-skid, 152, 158-159

oak, 28 Oarling, 4oars, paddles, oarlocks: suppli­

ers, 191 oil finishes: for in terior wood­

w ork/trim , 145, 160 okoume, 22, 27 Oysta 42, 73

paint, bottom : antifouling,137. 138-139

paint, finish/topsidesacrylic urethanes, 150-151,

152-153,157, 159 alkyd enamels, 150 Awlgrip, 153 chalking, 151, 153 color o f in re fabric print-

through, 42-44, 155-156 Deltron & Concept, 151 epoxy, 150-151, 157 epoxy com patible, 44 for exterior, 150-159 for hand application, 152,

153, 157, 158, 159 house (porch /deck) paint,

flat/w hite, 153 for interiors, 152, 159 LPU (linear polyurethanes),

150-152, 153, 157-158 m arine en im el, 138 for m odel, 66-67 non-skid, 152, 158-159 p repara tion /m ix ing /stir­

ring, 157-158 p ro tec tio n /h ea lth cautions,

151, 158 for spraying, 151, 152-153,

159 Sterling, 153wire stitches/fasteners and,

91, 121, 126 See also pain ting techniques

paint, prim eras conversion coating, 150,

157epoxy prim ers, 138,

150-151, 153-154. 157 painting techniques, 150-159

hand application, 152, 153,157, 158

m asking off, 137-138, 158,160

non-skid, 152, 158-159 pre-painting interior, 159 protective gear, 151, 158 rolling-and-brushing (tip­

ping), 138-139, 152, 157, 159

spraying, 151, 152-153, 159 tips/ru les for success,

156-158 panels. See hull panels Payson, Dynamite, 79 peel-ply, 39, 113-116

cellophane tape used as, 136 Peeper, 73plane, block. See block plane planer, power, hand: Makita

1805B, 47

planer, wood: Makita 2012 Power Feed, 18

plank-on-frame construction, 1 adapting to stitch-and-glue,

55plans, 19-20

enlarging, 60-64 sources, 187

pliers, lineman-type, 13, 17 pliers, parrot-peak: Knipex

KN6801, 18 plum b bob, 15, 17, 97-98 plywood, aircraft: for m odel­

ing, 61, 62, 65-66 plywood, m arine, 2

cold m olding, 123-126 domestic vs. im ported,

21-22, 72 bending characteristics/lim ­

itations, 57,58,62,65,6,95 for cabinet doors, 148 glued inlays in, 147 lam inated decks and cabin-

tops, 75 lam inated sheer clamp,

70-71, 73-75, 105, 108 lam inating long panels, 47 mahogany, 22, 27 ro t/m o istu re problem s, 23 scantlings, bulkheads, 72-73

scantlings, skin thickness, 73

scarfing panels, 45-50 sealing in terior surfaces,

100, 127, 143 selecting, 21-23 suppliers, 188-189 testing, 23 voids, 21-22, 23 yellow cedar, 28

plywood-on-frame construc­tion: adapting to stitch- and-glue, 55-56, 58-59, 60-64

Polliwog dinghy, 2, 26 polyester resin: bonding char­

acteristics, 29 polyurethane

adhesive (bedding/caulking com pound), 142,147-148, 159, 160, 162

foam, 142-143

rue

D e v l i n ’ s B o a t b u i l d i n g

P ort O rford cedar (yellow cedar), 28

power plane: Makita 1900B, 18 power saws, 10-12, 17, 18 print-through (telegraphing),

42-44, 155-156 profile, hull, 60-66 propane torch, handheld: for

softening cured epoxy,17, 12]

propeller, 139protective g ea r/sh o p safety, 17,

32 ,33-36,114,151,158 inform ation, 191 See also gloves; respirators;

safety glasses; Tyvek clothing

pum ps, for dispensing epoxy, 17,32

cleaning, 32-33, 34

random -orbit sander. See sander, random -orbit

rasp: for m odeling, 65 red oak, 28 repairs, hull, 169-170 respirators, 15-16, 17, 33, 34,

114, 136, 151, 158 beards and, 34 suppliers, 191 3M 6000, 15-16, 17

roller, 36, 132-133toothed (fiberglass tooling),

112-113 rolling-and-brushing (tipp ing),

132-133,152,157,159 rolling fram e/jig , 117-118,

120rollover, o f hull, 117-120

construction considerations, 100-101, 105

routers, ]6, 18, 169 Makita 3612BR, 16, 17 Porter-Cable 1001, 16

rubrails, 104-105,150,160,162 wood for, 23, 27

rudders, 127See also cheek blocks

safety glasses, 17, 34-35, 114, 158

sailmakers: list of, 188

sander, belt/d isc. See belt sander; disc sander

sander, random -orbit, 157;Porter-Cable 333 9, 16. 17

sander, vibrating: Makita B 04510 palm sander, 9, 16, 17

sander-polisher-grinderM akita9207,9-10,17,18,135 sanding and fairing hull

sheathing, 134-136 for scarf bevels, 48

sanding and fairingo f epoxy (exterior sheath­

ing), 132, 134-136 o f m odel, 66-67

sanding tools: dust collection systems for, 136

sandpaper/scuffing pads, 18, 136

for modeling, 66-67 for painting, 158 Scotchbrite pads, ] 47, 157,

158suppliers, 190 3M Stickit, 10, 17

sapele, 22 saw, cutoff, 18 sawhorses, 17 saws, power, 10-12, 17, 18 scantlings, 68 Scarffer 875 (scarfingjig),

46-47 scarfing

dim ensional lumber, 47, 160-161

jigs for, 46-47 length to-thickness ratios, 45 m arine plywood, 45-50 pre-scarfed panels, 46 stair-stepping (staircase

scarfing), 46-47 scissors, 15, 17Scotchbrite pads, 147,157,158 scribing

bulkheads, 15, 99-100 floor timbers, 108 stitch line (for wire stitches),

84scuppers, 148, 149 seams. See hull seam s/joints seam taping

o f bulkheads, 100 glassing box, use of, 33,

111-116 o f hull seams, 41, 75-77,

109-116tape layers, overlapping of,

111tape layers, prelam inated

sets of, 33, 111-116 See also fiberglass tape

seat thwarts: wood for, 23, 27 secondary bond, 29, 112 shaft log, 164-165

Buck Algonquin SL-125 FG, 165

shaft/ste rn tube, 139, 164 sharpening stones, 13, 17

DMT, 13, 17 lubricants, 13

sheer clamp, 42arrangem ents for, 73-75 lam inated. 70-71,73-75,105 types/installation, 103-106 wood for, 23, 25-26, 28

sheer guard, 104—105 wood for, 27, 28

sheer p lane/lift, 60-66 sheer spreaders, 68-69, 94-95,

105sheerstrakes: wood for, 23 shop. See workshop Sitka spruce, 25, 28 skeg, 77, 127

wood for, 23 sledgehammer, 18 sliding mechanism: for com­

panionway doors, 149 soaps/cleaners

hand cleaners, 17 for recoating (house paint),

153Solo Canoe, 73 solvents: acetone/lacquer

thinner, 34, 36 spreaders

bottom , 86-87 sheer, 68-69, 94-95, 105

spruce, 25-26, 28 square, fram ing/L-, 13, 17

extending (for lofting), 52 squeegee: use of, 17, 33, 36,

110-113,116,131-132

I n d e x

stapler, power (compressed- air), 125

SENCO LN4450, 18 station marks, 52-53, 62 steering: suppliers, 191 stem

installing, 128-129 joints/scantlings, 77-78 repair, 169transition jo in t, 87-90

stem band, 127 steps, 161stern, fantail. 57, 59 stitch-and-glue boatbuilding

advantages of, 1-6 vs. traditional plywood con­

struction, 55-56,77-78,79 stitches. See wire stitches storage

hull interior, access to, 144, 146-147

o f tools, 8-9See also w inter layup/storage

stringers, structural, 70-71, 73-75

wood for, 25 strop, for sharpening, 13 S urf Scoter, 4, 70, 73, 97,

100-101, 105, 118, 139, 143-144, 146-147, 152, 164-165, 168-170

table o f offsets, 61, 62 table saw, 18

blades, 12Rockwell Unisaw, 12

tabs, seam (epoxy filler): for hull stiffening, 96, 108, 112, 121

tack-and-tape construction (Instant Boats), 79

tanks: suppliers, 191 tape, fiberglass. See fiberglass

tape; seam taping tape, packing (strapping), 65,

66 , 68taping, seam. See fiberglass

tape; seam taping tape measure, retracting:

Stanley Powermatic,13-15, 17

teak, 27, 28, 160-161

teak oil, 27, 160-161 templates, 106 ties, wire. See wire stitches tiller: wood for, 23, 28 toerails, 105-106, 150, 160;

wood for, 27 tools, for stitch-and-glue boat­

building, 2, 6, 9-18 cleaning/lubricating , 36 for filleting, 109-111 for painting, 159 power, 9 -12, 17-18 sources, 187-188; sharpen­

ing, 13; for stitching,84—85; storage, 8-9

used /recond itioned , 16-17 towels/rags, 136 track and slides: for com pan­

ionway doors, 149 trailering: design considera­

tions, 73 transom: checking for hull

twist, 96, 112 transom p lane/lift, 60-66 trim, exterior, 16, 160-162

woods for, 23, 27, 28, 160-161

trim, interior, 16 wood for, 27, 28

twisting. See hull twist, longitu­dinal; wood grain

Tyvek clothing, 114, 132, 151, 158

vacuum bagging, 44, 47 varnish, 147, 150, 160

UV filters, 154 ventilation: o f b ilge /hu ll inte­

rior, 142-143, 144, 146-147

ventilators, 146-147 vinegar, white, 36

waterlinedesigned, 93-94 marking, 137-138

wax, furniture: as wood finish, 145

weight, displacem ent and bulkhead scantlings,

72-73 and skin thickness, 73

testing of. using flotation m odel, 68

white oak, 28 windows: suppliers, 190 w inter layup/storage:

design /construction con­siderations, 73, 79-80,126

W inter W ren, 73 wire, steel baling, 17 wire stitches

drilling holes for, 84, 88-89 removal of, 91, 108,

121-122 stitching technique, 84—86,

88-91 wire for, 91

wood. See lumber, dim en­sional; plywood, m arine

w ooden boats: construction techniques for, 1-6

wood finishesforinteriorsurfaces, 152,159 for in terio r w oodw ork/trim ,

145, 160 See also Cetol teak finish;

epoxy sealer/coating; oil finishes; paint, bottom ; paint, finish/topsides; paint, prim er; teak oil; varnish

wood flour: filler/filleting m ixture, 37, 38, 49, 109-111, 115, 136

wood grain, 24—26and bending characteristics,

25-26 for bungs, 145 end grain, epoxy-sealing, 100 tw isting/grain runout,

25-26 workbench, 8-9 workshop, 7-9

heating, 8, 30, 32, 156 size of, 2, 7-8

worm shoe, 127

Xynole, 44, 130

yellow cedar, 28, 106 plywood, 28

198

In t e r n a t i o n a l Ma r i n e

A d i v i s i o n o f T h e Mc G r a w -H i l l , Co m p a n i e s