What is the minimum pressure required in the SECUMAR bottles?

• A. 1200 psig
• B. 3600 psig
• C. 2400 psig = 35 lbs lift at 50 fsw
• D. 4800 psig

Answer: (C)

The key idea is how a bailout bottle’s buoyant lift depends on how much gas is inside the bottle at a given depth. A fixed-volume bottle displaces the same amount of water, but the weight of the gas inside changes with pressure. As you descend, ambient pressure compresses the gas, increasing its mass and total weight, which reduces the net lift the bottle provides. The minimum pressure is the level at which the SECUMAR bottle still delivers the required amount of lift at the test depth, according to the manufacturer’s data. So the correct option is the one that matches that published lift-for-depth specification. Lower pressures would not meet the needed lift, while higher pressures would exceed the minimum but are not the value defined as the minimum.