# I am doing a science experience prooving giant ships can float

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1. Feb 20, 2013

### duskwood100

I am trying to prove why ultra large crude carriers and other kinds of ships can float, and why they are stable in water?

The experiments need to be simple and doable at home. I also could use some formula for stability and dead weight and so on. Could someone please help me, maybe point me in the right direction

I have basic background in maritime apprentice motorman. I am doing this however as a physics experiment.

2. Feb 20, 2013

### FlexGunship

No one's going to say anything?!

3. Feb 20, 2013

### ModusPwnd

I guess that floating small models in your bathtub is not what you want?

4. Feb 20, 2013

### Thinker007

With respect to proving the ships float, I was going to suggest simply taking the dimensions of the ship LxWxH and comparing the weight of water to the published weight of the ship - but that also seemed a bit obvious and a bit crude, so perhaps that's also not what was wanted?

5. Feb 20, 2013

### etudiant

Presumably the question relates more to stability in the water, why do they not turn turtle? Given the low density of the VLCC payload, that seems a reasonable question.

Afaik, for lateral stability the answer revolves around the center of gravity vs the center of bouyancy of the ship. If the CG gets too close to or even above the CB, bad things can happen. Longitudinal stability is another question, suggestions from more knowledgeable contributers will be needed.

6. Feb 20, 2013

### SteamKing

Staff Emeritus
As a first attempt, I suggest you familiarize yourself with buoyancy and Archimedes principle.

7. Feb 21, 2013

### duskwood100

ty 4 all the help

8. Feb 21, 2013

### SteamKing

Staff Emeritus
For ships of normal proportions, the CG is often located above the CB. When the CG is located above a point called the metacenter, bad things can happen.

9. Feb 21, 2013

### Khashishi

I think the gist of your experiment is that a larger ship is more stable than a smaller ship, right?

Well, you could build miniature ships of all different sizes and put them in a wave tank and see how they move. Those freight shipping liners are huge, so they aren't really affected by waves. Well, they can still tip over on some bad occasions.

On the science side, you can read up on Reynolds number and see what it says about turbulence which could make for a bumpy ride.