Determining Minimum Wing Lift

[RobPNW]

This is probably more of a physics question than anything. Determining weight to achieve neutral buoyancy at the surface is pretty easy. How exactly does one determine added negative buoyancy at deepest depth? In theory would this not determine minimum wing lift needed without ditching weight?

Here’s my example. Let’s make the scenario as simple as possible. Warm water diving with minimal exposure gear and you need 6 pounds to just sink with the wing empty. You don’t plan to exceed the max recreational depth of 130 feet. How do you determine how much additional negative buoyancy you would have at max depth or what your minimum wing lift would be?

Yeah I could get something that is more than enough based on other people’s experience. Just wondering if there was a way to determine a semi accurate answer through tables or calculations etc.

Thanks in advance,
Rob

 

[tbone1004]

wetsuits are roughly 2lbs/mm of positive buoyancy, it's a good rule of thumb. Assume they have 0 residual buoyancy, then add mass of the gas in the tank, and I like to add about 15lbs so you can comfortably float at the surface at the start of the dive. Gets close

 

[RobPNW]

wetsuits are roughly 2lbs/mm of positive buoyancy, it's a good rule of thumb. Assume they have 0 residual buoyancy, then add mass of the gas in the tank, and I like to add about 15lbs so you can comfortably float at the surface at the start of the dive. Gets close

Thanks Tbone. What about a short sleeve shorty in 3mm? Roughly 4 lbs? Plus about 6 lbs gas plus 15 lbs safety gets me to 25 lbs for a travel wing. Sound about right?