Air Lift in Water: How Much Does it Lift?

[JP Mikl]

Hi,

One cubic foot of air will lift approx 64 lbs in water (basically). So if you start at a xxx depth with a balloon that is one cf, as it rises and expands the lift capability increases, right? What if the container was an aluminum sphere. Actually, say you have 2 same size spheres, both are one cf in volume, but in one you increase the psi to 10 times that of the other. Neither will be able to actually expand as they rise to the surface, so does this mean that even if one has more air (under pressure) both will have the same exact lift capability?

Thx,

Jeff

 

[JaredJames]

What if the container was an aluminum sphere. Actually, say you have 2 same size spheres, both are one cf in volume, but in one you increase the psi to 10 times that of the other. Neither will be able to actually expand as they rise to the surface, so does this mean that even if one has more air (under pressure) both will have the same exact lift capability?f

If neither container can expand, the internal pressure is irrelevant. However, if the pressure increase comes from injecting more air into the one container than the other, you will have a mass increase which means a higher (all be it slightly) weight, recuding the overall lift capacity.