SERENITY PORT MAIN BULKHEAD REPLACEMENT

by Eric Mueller

and Roger Anderson

Starboard Side no moisture on the meter and taps out good

Backing plate removed. The holes here are actually in good shape. No ovaling and the wood is solid .

Port Side No moisture on the meter and taps out good.

Back side looks good too

Bottom needs a little retabbing but not in too bad shape

Backing plate removed shows ovaled holes and rot behind the chain plate.

This is a sign of impending failure

Angled section removed you can see what only a little force did to

the rotted area.

The back side and a closer look at the damage

Bulkhead removed. A slot was cut from the bulkhead to the hole for the sink.

From below

View from the head

The new larger bulkhead next to the original used as a template

The new bulkhead fits well, we intentionally left a gap to the hull to

prevent creating a hard point.

The new bulkhead slid right into the slot

We extended the chainplate and here is the upper backing plate helping hold the

bulkhead in place while we work on it.

We used polyurethane expanding flotation foam to form the filets

The foam was a pain to shape, we did not get it perfect

Upper portion ready to sand and glass

Upper portion is glassed in. We used a Bi-axial glass with a matt sewn on (knytex)

Not the neatest fillet. Glass was laid in place dry and marked for cuts along the curve. The glass was then cut before proceeding.

It is hard to see but the black line is where a cut was made and the fiberglass overlapped.

The neighboring bulkheads below were re-tabbed at the same time

Things are not perfect, but they are functional. The piece for the slot we removed to get the old bulkhead out and the new one in was replaced and epoxied into place as was the gap at the shelf to bulkhead joint. The final

glassing is going to be the shelf to the bulkheads. It is more for rigidity than adding strength.

To lay the glass we used a big plastic mortar tub. This allowed the epoxy to spread out. We mixed multiple smaller batches of slow epoxy and poured them into the tub. We timed the mixing of the batches at 2

minutes of fast stirring once both components were put together. It is not recommended to use the same mixing bucket for multiple batches so we had about a half dozen of the 2 qt plastic paint buckets. We then laid the

glass into the epoxy to just saturate it. We took the saturated glass, put it in place and used a ridged metal fiberglass roller to ensure the fiberglass was flat and there was minimal excess resin. We immediately cleaned up

any excess that did occur. You do not want wet epoxy in the bilge!A couple of notes about safety and clean up. We went through lots of gloves and chemical resistant suits. It is worth the investment. Don’t

forget the hats and glasses. Everything that was not getting glassed got covered in 6 mil plastic

sheeting taped up with blue masking tape.Epoxy can be left to harden in the mixing buckets and will peel away from the sides. We cleaned our plastic stir stick, tools, and tub with alcohol and

rags. To clean ourselves since there does not seem to be any perfect way to keep the epoxy under control we used vinegar. Yes vinegar. It makes a great cleanup solvent. I always take a shower with it after epoxy work

even if I think I have managed to not get any on me. I do not know what the chemical reaction with acetic acid and epoxy is so I did not want to

use it on tools or items that were going to be used for epoxy again, but it sure works great for removal of uncured epoxy on skin.

I will try and get some additional pictures of the epoxy process. It is kind of hard to handle a camera covered in epoxy.

The wood used was BS1088 marine grade plywood from MacBeaths hardwood in Berkley. Make sure the plywood is stamped that it meets the BS1088 standard if you decide to get it from there they also have regular

13 layer marine plywood and the workers really do not know the difference. The advantage of the BS1088 plywood is that it has no voids is

stronger, stiffer, and lighter than the comparable 13 layer marine plywoods I have found.

I eventually replaced the starboard bulkhead as the hidden edges turned out to have some rot. The Starboard bulkhead that the chain plate is

attached to is attached to the liner and not to the hull. The plywood on the hanging locker side is what is attached to the hull. My solution was

two fold. I had already lengthened and offset the chain plate to attach to the glassed in bulkhead as well. When I replaced the upper portion that was originally the only attachment for the chain plate I epoxied it to the

liner essentially creating a single bulkhead sandwich. If someone wants I can post some pictures I have from that operation.