The Most Efficient Boat Hull at Varying Water Speeds

Lauren Casulli

Question

Which boat hull is the most efficient at different water speeds?

Purpose

The purpose of this experiment was to determine the most efficient boat hull.

Background Information

There are five main hull shapes in use today: Flat Bottom Catamaran V Bottom Tri Hull Pontoon

Hypothesis

The most efficient boat hull at any speed is the tri-hull because the air tunnels reduce drag.

Materials Wood (3.6m) Water pump Dual Force Sensor Trough Band saw, table saw, drill, sander Eye hooks (4) String Copper pipe Tygon tubing Ball valve Pipe clamps

Procedure

1. Draw outlines of top view and side view of boat 2. Cut wood3. Sand and finalize shape4. Attach force sensor to one end of trough5. Attach eye hooks to bow of boat, connect string from

boat to sensor6. Fill trough with water, situating pump.7. Turn pump on and allow water speed to reach 0.0318

m/sec, place first boat in trough and record sensor reading for ten seconds. Repeat two more times.

8. Repeat with other three boats, do not change water speed

9. Change the water speed to 0.0477 m/sec and measure the force on all four boats with sensor

10. Repeat at 0.0636 m/sec

Photographs – Pump Configuration

Trough Set Up

Hull Bottoms

Boat Hull TopsBoat Hull Tops

VariablesIndependent

Variables Water speed Hull shape

Dependent Variables

Force on hulls

Control RaftConstants Pump Trough Sensor Water speeds

GraphsThe Average Drag of Different Hull Types at a High Speed

Raft Flat Bott. V Bottom Tri Hull0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4 0.3506

0.1841

0.10310.08439

The Average Drag of Different Hull Types at a High Speed

Hull Type

New

tons

The Average Drag of Different Hull Types at a Medium Speed

Raft Flat Bott. V Bottom Tri Hull0

0.05

0.1

0.15

0.2

0.25

0.2146

0.04409 0.03135 0.02061

Average Drag of Different Hull Types at a Medium Speed

Hull Type

New

tons

The Average Drag of Different Hull Types at a Low Speed

Raft Flat Bott. V Bottom Tri Hull0

0.010.020.030.040.050.060.070.080.09

0.10.110.120.130.140.150.16 0.1493

0.02656

0.02259

0.001567

Average Drag of Different Hull Types at a Low Speed

Hull Type

New

tons

High Raft Flat Bottom

V Bottom Tri Hull

Trial 1 0.3698 0.1780 0.1005 0.08993Trial2 0.2785 0.1822 0.1018 0.08416Trial 3 0.4034 0.1922 0.1071 0.07907

Averages 0.3506 0.1841 0.1031 0.08440T-TestsRFB 0.04263 FBVB 0.0007465 VBTH 0.06600RVB 0.001349 FBTH 0.005291RTH 0.01992

Data – High Speed

Medium SpeedMedium Raft

Flat Bottom V Bottom Tri Hull

Trial 1 0.2164 0.04967 0.03168 0.01497Trial 2 0.2177 0.03822 0.03171 0.02297Trial 3 0.2096 0.04439 0.03065 0.02388

Averages 0.2146 0.04409 0.03135 0.02061

TTESTRB 0.0007037 FBVB 0.06268 VBTH 0.07156RVB 0.0001398 FBTH 0.05607RTH 0.0005502

Slow SpeedSlow Raft Flat Bottom V Bottom Tri HullTrial 1 0.1580 0.02000 0.02216 0.0005921Trial 2 0.1523 0.03006 0.02337 0.003039Trial 3 0.1375 0.02963 0.02223 0.001069

Averages 0.1493 0.02656 0.02259 0.001567T-Tests

RFB 0.03970 FBVB 0.3252 VBTH 0.0002997

RVB 0.03557 FBTH 0.01257

RTH 0.02857

Conclusion

The hypothesis was supported as the Tri-Hull consistently had the least amount of resistance at any speed of water.

The V-bottom was a close second as the best hull as it had significantly less resistance than the flat bottom and raft. There is almost no significant difference between the V bottom and Tri-Hull.

Significance of ExperimentThis experiment was significant

because it contributed to the idea that one boat hull is the most efficient at any speed of water. But this experiment did not take into account the activity being performed, such as a war-ship versus a fishing boat, as well as the sea state.

Work CitedKnow Your Boat. (2003). BoatUS Foundation. Retrieved October 19, 2010, from BoatUS

Foundation website: http://www.boatus.org/onlinecourse/reviewpages/boatusf/

project/section1.htm

Zidock Jr, A. (1999, July/August). Boat Hull Design. Retrieved September/ October, 2010,

from Commonwealth of Pennsylvania Fish and Boat Commission website: http://

www.fish.state.pa.us/anglerboater/1999/julaug99/boathull.htm