At 50 fsw, the SECUMAR minimum pressure of 2400 psig provides how many pounds of lift?

• A. 55 lbs
• B. 35 lbs
• C. 25 lbs
• D. 45 lbs

Answer: (B)

Air in the buoyancy bladder creates the lift, and the amount of air you have in that bladder depends on the pressure you’ve pumped in and the depth you’re at. At depth, external water pressure compresses the air, so the same cylinder pressure yields a specific bladder volume and thus a specific amount of lift. For this SECUMAR unit, at 50 fsw the data shows that inflating the bladder to a cylinder pressure of 2400 psi provides about 35 pounds of lift. That’s the published lift for those conditions, which is why 35 lbs is the correct answer. The other numbers would correspond to different depths or different air volumes/pressures not specified here.