Why Boats Are Shaped The Way They Are

Hi! My name is Rachel. This is my science fair project.

Introduction:My little brother loves everything boats. And

that makes me curious on why do boats have different shapes? What is the best boat out there?

By experimenting with the shapes, I think I can find out the answers to my questions.

Research:I did some study over the

internet and found that there are many kinds of boats with many kinds of shapes.

First let me tell you the meaning of “Hull”. Hull is the body of a boat or ship that is waterproof.

There are 4 main hulls that are commonly known, and they are: round-bottom hull, deep-vee hull, flat-bottom hull, and multi-hull; which mean that it has 2 or more hulls attached together.

Hypothesis:Multi hull boat will be the fastest. Round hull

boat will maneuver easiest because the bottom is round. Flat hull boat will be the most stable because the bottom is flat, it looks like it is very steady.

Materials:Styrofoam and plastic tub

Preparations:My dad helped me by carving the boat

shapes. And then I color them.

Experiment:1. I marked the plastic tub with measurement in

inches. That way I will be able to find out how far each boat moves.

2. I marked the boats with what type of hull they have. The red boat has round-bottom hull, the green boat has deep-vee hull, the yellow boat has flat-bottom hull, and the blue boat has multi-hull; which means that it has 2 or more hulls attached together.

3. I put water in the tub.4. I gave each boat a little push to see which one

can move quickly.

Experiment Cont.:As you can see here, the red round-

bottom boat is moving, but not straight. It maneuvered or changed directions easily and it stopped at 13” mark.

The green deep-vee hull moved very easily and a little bit straighter than the red round-bottom boat. It also moved a lot faster. It reached the 18” mark in no time. 

The yellow flat-bottom hull moved a lot slower and it moved very straight. And it stopped only at the 11” mark.

And the blue multi-hull moved easily and straight. It stopped at the 18” mark.

Experiment Cont.:I then added weight to each

boat to see which type of hull moves best as I added the weight. 

As you can see here, the red round-bottom boat tipped over when I added some weight to it.

The green deep-vee was tipping slightly.

The yellow flat-bottom had no problem carrying the weight, it was very stable, and it moved straight. The same thing happened to the blue multi-hull boat.

Experiment Cont.:I kept track on everything and put the results

in charts:

Conclusions:My hypothesis was correct. However there is no really the

best boat. Each boat’s shape is special and their shapes help them in doing their tasks at best.  

For example: Tugboats have round-bottom hull so that they can move around the water easily. Tugboats help pulling boats and ships that cannot maneuver easily such us barge boats.  

Barge boats have flat-bottom hull, even though they move slow and straight, but they are very stable, perfect for carrying cargos.  

Ski boats have deep-vee hull so that they can move fast easily. A lot of modern day ferryboats have multi-hull, the shape

gives them stability and speed at the same time.  This was a very fun experiment, I enjoyed it and my brother

really enjoyed watching me doing the experiment.

Tugboats have round-bottom hull:

Barge boats have flat-bottom hull:

Ski boats have deep-vee hull:

Catamaran ferryboats have multi-hull: