Rachel conducted a science fair experiment to determine which boat hull shape is best by testing models with different hull shapes. She found that round hull boats maneuvered best but were unstable, deep vee hull boats were fastest but tipped, flat hull boats were slow but most stable, and multi-hull boats were both fast and stable. Rachel concluded that each hull shape is suited to different boat purposes, like round hulls for maneuverable tugboats and flat hulls for cargo-carrying barge boats.

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

2. 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.

3. 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.

4. 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.

5. Materials:
 Styrofoam and plastic tub

6. Preparations:
 My dad helped me by carving the boat shapes. And
then I color them.

7. 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.

8. 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.

9. 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.

10. Experiment Cont.:
 I kept track on everything and put the results in
charts:

11. 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.

12.  Tugboats have round-bottom hull:
 Barge boats have flat-bottom hull:

13.  Ski boats have deep-vee hull:
 Catamaran ferryboats have multi-hull: