L.O.M.A.C.(Littoral Operation Multipurpose Auxiliary Craft)

Casey Connor, John Sebastian,Austin Graham, and Scott Naro-Norman

Advisor – Dr. Zborowski Graduate Assistant – Mark Cencer

Purpose

? The purpose of Team LOMAC is to design a double chine monohull vessel to operate in the littoral zone. ? The littoral zone is the area close to the shoreline

characterized by breaking waves.

? The monohull will then be experimentally tested and compared to the catamaran design.

History

? There were 2 Types of Hulls that were chosen:? V-Bottom Catamaran ? Savitsky Double Chine Monohull

? The catamaran was built last year and is going to be compared to the current monohull.

Specifications

? Hull configuration: Double Chine Savitsky Monohull

? LBP: 1.524m (60.35 in.)? LOA: 1.626m (64.39 in.)? Draft: 0.07m (2.77 in.)? Beam: 0.26m (10.30 in.)? Displacement: 160.53N (36 lbs)? Deadrise at Transom: 15° on 1st chine,

45° on 2nd Chine

Requirements

? Vessel must have good sea-keeping properties, particularly in the littoral zone.

? Model must be able to achieve a speed of 13 knots.

? Vessel must have good course-keeping characteristics.

? Model must have good maneuverability and controllability.

How a Double Chine Savitsky Monohullworks. ? A chine is an edge on the hull that separates the

bottom from the sides.? Lower chine is flatter to create as much lift as

possible.? Upper chine is to push water away from the hull to

lower the resistance on the first chine.? Double chine Savitsky monohull is a design that

balances the lift force on the hull against the resistance forces on the hull.

? As the model increases to design speed the hull will lift and plane on the lower chine.

DWG#: 1001-1 Rev: -

Project Title: 3-D HULL DESIGN, FRONT

Project Name: L.O.M.A.C

Draftsman: Brian Biera DATE: 4/12/2004

Florida Institute of Technology

DWG#: 1001-2 Rev: -

Project Title: 3-D HULL DESIGN, SIDE

Project Name: L.O.M.A.C

Draftsman: Brian Biera DATE: 4/12/2004

Florida Institute of Technology

Design

1) Using design specifications given by Dr. Zborowski, a 3D model was rendered in ProSurf.

2) Upper and lower chines added.

3) Entire hull was faired to final design specs.

4) Stations were assigned for manufacturing purposes.

Strongback

1) Import ProSurf design into AutoCAD and print out transverse view of boat stations.

2) Glue station printouts to plywood and cut out.

3) Fasten plywood stations to the strong-back via angle iron.

Fairing Plug

1) Cut polystyrene foam to fit between the plywood stations.

2) Fair the foam until it is even with the plywood stations.

3) Paint the surface of the foam/plywood hull with latex paint.

4) Apply Duratec Sanding Primer on top of the painted surface.

Fiberglassing

1) Cut Fiberglass to fit plug.

2) Coat plug with wax releasing agent.

3) Mix epoxy at a 2 part resin to 1 part hardener.

4) Saturate fiberglass with epoxy mix.

5) Place fiberglass on plug and remove air bubbles.

6) Allow to cure.

Finishing

? Mix microballoons with epoxy until a mayonnaise consistency is achieved.

? Apply mix to areas that need to be built up.

? Sand smooth.

Prototype Design Requirements:

? Length Between Perpendiculars (LBPP): 50 ft? Longitudinal Center of Gravity (LCGP): 16.8 ft? Displacement (? ?P): ~ 36,000 lb? Total Resistance (RT): 4,842 lb? Vessel Speed (VP): 40 knots? Effective Horsepower (EHPP): 594 HP? Shaft Horsepower (SHPP): 1188 HP

Model Design Requirements:

? Scale (? ): 1:10? Displacement (? ?m): 36 lbs? Model Speed (Vm): 13 knots? Effective Horsepower (EHPm): 0.19 HP? Shaft Horsepower (SHPm): 0.38 HP

Propulsion and Maneuvering

21

20

10 x 2x 2 14

30 x 2

32 x 2

x 2 13

19

11

12

? = 2.00"

17

42 x 2

36

High Torque Servo

Electric Motor #1

Electric Motor #2

42 x 2

+- Speed

Controller

+- + -

+-

Ser

vo

ANT.

Receiver

Spe

ed C

ontro

l

Bat

t.

Receiver Battery

Wiring Diagram

Propulsion

? Twin Electric Motors? 700BB Turbo 8.4V 15A

? Dual 3/16” Diameter Stainless Steel Drive Shafts

? Twin 2” Diameter, 3 Blade Brass Propellers

Propulsion: Components Electric Motor Specifications

Nominal Voltage = 8.4VOperating Voltage Range = 4.8V - 12VNo-Load Speed (approx.) = 14,700 rad/minIdle-Current Drain (approx.) = 2.5ACurrent Drain at Max Efficiency (approx.) = 15ABlocking-Current Drain (approx.) = 75AMax. Efficiency (approx.) = 72%RPM at Max. Efficiency = 19,318 rpmWeight = 350g = 0.350 Kg

Propeller Diameter: 2”Number of Blades/Propeller: 3Material: Bronze Cast

Motor Speed: 19,318 Rev/min

Maneuvering

? Twin Spade Rudders? High Torque Servo

Controller? Dual Steering Control

linkage System

Maneuvering: Components

High Torque Control Servo

Output Torque: 92.0 oz-in

Servo Arm Turn Speed (60 degrees): 0.16 seconds

Rudder Blade Height: 2 5/8”

Cooling Fan Assembly

1

2

F1

5V 0.19AFAN

VI3 VO 2

AD

J1

U1LM317L

R1220 Ohm

R2220 Ohm

R3220 Ohm

R4220 Ohm

BAT19V

Model Video:

Bill of MaterialsFind # Resource Matl. Units Std. Rate Total Cost Qty Vendor / Supplier

1 96.5" x 24.5" x 6-3/8" Polystyrene sheet $43.58 $87.16 2 sheet Vector Works2 Latex Paint gal $5.00 $5.00 1 gal Home Depot3 1.25" x 1.25" x 60" Angle Iron Lft $1.45 $14.50 10 Lft Home Depot4 Woven Roven Fiberglass, 18oz weight yd² Donation $0.00 3 yd² Florida Tech5 Resin / Epoxy (Resin & Hardener) gal $35.00 $210.00 6 gal www.E-Boat.net6 Duratec Sanding Primer gal $55.20 $55.20 1 gal Duratec7 1/4" x 48" x 96" Plywood sheet $7.30 $14.60 2 sheet Home Depot8 Bondo All-Purpose Putty Liter $5.95 $17.85 3 Liter Home Depot9 Fiberglass, 9oz weight yd² Donation $0.00 5 yd² E-Boat

10 LC4322 (Traxxas EVX Speed Control E-Maxx) ea $119.99 $119.99 1 ea Tower Hobbies11 KC1265 Peak Performance Power Max Pro 3000mAh E-Maxx ea $52.99 $52.99 1 ea Tower Hobbies12 LXENN0 Futaba 2PL 2CHL AM Transmitter w/2 servos ea $64.99 $64.99 1 ea Tower Hobbies13 LXSP02 (Traxxas 3-Channel Receiver T-Maxx) ea $26.99 $26.99 1 ea Tower Hobbies14 LXJH35 (11" 1/8" dia. Antenna Tube w/ Cap) ea $0.95 $0.95 1 ea Tower Hobbies15 KC1064 DuraTrax IntelliPeak AC/DC Twin Pulse Charger ea $74.99 $74.99 1 ea Tower Hobbies16 3m Respirator Masks ea $4.47 $8.94 2 ea Walmart17 MEKP (Methyl Ethyl Ketone Peroxide) Hardener 4oz tube $3.99 $15.96 4 ea Boaters World18 Hull Labels sheet $15.00 $15.90 1 ea Custom Engraving Co19 Super Glue tubes $1.39 $5.90 4 ea Melbourne Beach Hardware20 Sandpaper (various grit) pk $2.97 $14.86 5 pk Home Depot21 LXERH8 Futaba Receiver Antenna Wire 500mm mm $0.85 $0.85 1 pk Tower Hobbies22 LXDZ48 Ram Bilge Pump Boat Saver 6-12V ea $25.99 $25.99 1 ea Tower Hobbies23 LXJ778 Switch/charge jack mounting set kit $3.29 $3.29 1 kit Tower Hobbies24 LX0947 Airtronics Switch Harness Standard Z ea $6.69 $6.69 1 ea Tower Hobbies25 LXF2X3 Batteries, AA, Fuji 48-pk pk $20.99 $20.99 1 pk Tower Hobbies26 LXK283 CA Glue 20oz. Thin btl $6.99 $6.99 1 btl Tower Hobbies27 Manuevering - $57.37 $57.37 - - 28 Propulsion - $210.43 $210.43 - Tower Hobbies29 Hardware and Supplies - $133.49 133.49 - Home Depot / Lowes

$1,272.86Total Project Expenditures

Gant Chart71 LOMAC PROJECT (Summer Semester Term) Mon 5/10/04 Sat 7/17/04

72 Revise Prosurf Drawings Mon 5/10/04 Fri 5/28/04

77 Export Prosurf Drawings to GHS format and calculate hydrostatic values from GHS Mon 5/10/04 Fri 5/28/04

78 Export Prosurf drawing into .dxf format (maintaining same scale) Mon 5/10/04 Mon 6/14/04

82 Construction of Hull #2 Mon 6/14/04 Wed 6/16/04

90 Assemble Propulsion system (uninstalled) Mon 5/17/04 Fri 6/25/04

91 Assemble propulsion System Mon 5/17/04 Mon 6/7/04

92 Test propulsion system Mon 5/17/04 Mon 6/7/04

93 Make adjustments and changes based on test results Mon 5/17/04 Mon 6/7/04

94 Retest propulsion system Mon 5/17/04 Mon 6/7/04

95 Install into hull Mon 6/21/04 Fri 6/25/04

96 Assemble Manuevering System (Uninstalled) Mon 5/17/04 Wed 7/7/04

97 Assemble manuevering system Mon 5/17/04 Mon 6/7/04

98 Test manuevering system Mon 5/17/04 Mon 6/7/04

99 Make adjustments and changes based on test results Mon 5/17/04 Mon 6/7/04

100 Retest manuevering system Mon 5/17/04 Mon 6/7/04

101 Install into hull Mon 6/28/04 Wed 7/7/04

102 Make sure all seals are watertight Sun 7/11/04 Sun 7/11/04

103 Construction complete Mon 7/12/04 Mon 7/12/04

104 Testing Mon 5/31/04 Sat 7/17/04

105 Generate a list of test parameters for LOMAC Mon 6/28/04 Mon 7/5/04

107 Generate a conceptual schedule for testing LOMAC Fri 7/9/04 Fri 7/9/04

108 Standardize a form for test data entry Mon 5/31/04 Mon 5/31/04

109 Initiate testing Fri 7/9/04 Tue 7/13/04

110 Test Data Analysis Fri 7/9/04 Tue 7/13/04

111 Conduct testing Fri 7/9/04 Mon 7/12/04

112 Determine if test data results are acceptable Tue 7/13/04 Tue 7/13/04

114 Collect all test data: Final Analysis and Draw Conclusions Tue 7/13/04 Tue 7/13/04

115 What went right Tue 7/13/04 Tue 7/13/04

116 What went wrong Tue 7/13/04 Tue 7/13/04

118 Draft Final Report Sat 7/17/04 Sat 7/17/04

119 Present Final Report Thu 7/15/04 Thu 7/15/04

Testing

? Center of Gravities? Rolling Frequency? Displacement? Center of Buoyancy? Speed

Center of Gravities

? Longitudinal center of gravity was found using the Balance experiment.? It was found to be

22.625” from the aft perpendicular.

? Vertical center of gravity was found using the Inclining Experiment. ? It was found to be 2.74“

from the baseline.

Roll Frequency

? The roll frequency is relative to a vessels ability to right itself.

? Model oscillates until it comes to rest.

? Average time per roll is 0.6165 seconds.

? Constant rolling coefficient is 5.2744.

Displacement

? Archimedes Principle states that the dry weight of an object is equal to the weight of the water which it displaces.

? Found by weighing model.? Hull displacement is 16.8 lbs.? Allows 19.2 lbs for instrumentation and

ballasting.

Center of Buoyancy

? Location of where the sum of all the buoyant forces act on the hull.

? Determined from the Hydrostatic Curves generated on GHS.

? Found to be 9.216” aft of amidships.

Speed

? Model velocity was determined by measuring the amount of time elapsed over a known distance.

? Model achieved 2.5 knots.? Model was designed to reach 13 knots.

Monohull vs. Catamaran

? Monohull? Center of gravity located

at 22.625” from aft and 2.74” from the baseline.

? Rolling coefficient is 5.2744.

? Displacement is 16.8 lbs.? Center of buoyancy

located at 9.216” aft from amidships.

? Experimental velocity of 2.5 knots.

? Catamaran? Center of gravity located

at 30.780” from aft and 6.81” from the baseline.

? Rolling coefficient is 0.2170.

? Displacement is 31.8 lbs.? Center of buoyancy

located at 11.610” aft of amidships.

? Experimental velocity of less than 2 knots.

Testing Analysis

? The monohull was lighter than the catamaran therefore it is easier to plane.

? With respect to hull resistance, the monohullis more efficient.

? The low rolling coefficient exhibited by the catamaran suggests greater stability in comparison to the monohull for littoral zone operation.

Conclusion

? A double chine Savitsky monohull was successfully designed, manufactured and fitted with propulsion.

? The vessel’s sea-keeping abilities and static stabilities were determined.

? Tests were compared between the monohulland the catamaran hulls.

Recommendations

? Increased propeller diameter.? Increase depth of propellers.? Improved driveshaft coupling.? Possible gearbox.? Increased freeboard.? Installation of an additional bulkhead.

Acknowledgements

? Dr. Zborowski? Dr. Thosteson? Dr. Wood? Mark Cencer? Brian Biera

References

? Battacharyya, Rameswar. Dynamics of Marine Vehicles. New York: Wiley. 1978.

? Cencer, Mark, et. Al. Littoral-Operation Multipurpose Auxiliary Craft. DMES. Florida Institute of Technolgy. 2003.

? Elliot, Henry. Adventures in Cheap. Professional Boatbuilder. June/July 1999.? Gilmer, Thomas C.and Johnson, Bruce. Introduction to Naval Architecture.

Annapolis, MD: Naval Institute Press. 1982.? Littoral Combat Ship. United States Navy Warfare Development Command.

February 2003.? Polyester Tooling. Cook Composites and Polymers Co. 1997.? Savitsky, Daniel, Roper, John, and Benen, Lawrence. “Hydrodynamic

Development of a High-Speed Planing Hull for Rough Water”. Proceedings of the Ninth ONR Symposium on Naval Hydrodynamics. August, 1972.

? Surfacing Clay Models and Patterns. Hawkeye Industries. April 3, 2003. www.duratec1.com

? Zborowski, Andrew. Study of Ship Dynamics in Littoral Waters. DMES Comprehensive Engineering Project. Melbourne, FL: Florida Institute of Technolgoy. 2002.

Questions?

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