unsure...

[Walter]

scubapunk-17055,

You missed the point. A rigid container will displace X amount of water (22 tons in the example). It must weigh more than 22 tons to sink. It does not matter what it contains. What matters is total density. Of course the contents will determine density, but the container would not become more buoyant after filling it with air (as indicated).

 

[scuba-punk]

right-o. i guess i wasn't clear on what i was trying to say. most people say weight instead of density. if you fill that volume with lead shot, it's density would be different than if filled with air. but this is all assuming that the volume is actually hollow and can be filled with anything. in any way, shape or form; mass per unit volume (or density) is the key.

 

[Big-t-2538]

Walter once bubbled...
Big-t-2538,

"That means that it would have to weight approximately 22 tons to sink with no air trapped inside to act as a bouyant force."

Nope. It does not matter what is inside, air, water, lead - it doesn't matter. If the volume remains the same, it will have the same buoyant force. Putting air inside a rigid container does not increase its buoyant force.

I'm retarded...I do that from time to time....ramble something in there that isn't right. I apologize....I renonce my position as an intelligent engineer...I'll just stick to beer....sweet sweet beer...and turkey

 

[Walter]

Beer, beer, amber and clear
not half as sweet as a woman's lips
but the rest of this poem will surely get me in big trouble.

 

[John C. Ratliff]

As a safety professional, I need to tell you that you really must get an engineer to draw up the design and sign off on it. If you don't, and someone is hurt, you may have problems beyond what you would normally have.

My son is a mechanical engineer, and for an underwater habitat you need to really understand material strengths, interactions with sea water, electrolysis of dis-similar metals/materials in sea water, etc. He or she (there are now more qualified PE's who are women than there used to be) can also help on calculating your displacement problem. However, if the design is at all complex, then you probably need to make a scale model and actually measure the displacement of the model, and calculate the real-sized habitat from that reading.

If you want to really understand some of the problems, read Cousteau's World Without Sun . He describes the trials of putting a habitat into the Red Sea, and some of the other problems this project overcame. At one point, they lost one of their habitats, and it went bumping down the reef to a deeper level. The book should be available in a good used-book store.

SeaRat

 

[BNT77]

I agree and ive read all of Cousteau's books, ive read "Living and Working in the Sea" by Koblick and Miller. And i do plan on having a model built and tested as well as the plans redone by an engineer. Those all ARE in my plans...i just thought id get oen step closer by getting the basic information for displacement and such all ready.