A hydrostatic release mechanism for a liferaft __________.

Correct Answer: Option C — must be submerged to a certain depth to release automatically

SOLAS and 46 CFR standards dictate that hydrostatic release units operate via a pressure-sensitive diaphragm. The unit must be submerged to a specific depth, typically between 1.5 and 4 meters, where surrounding water pressure overcomes internal spring tension to activate the cutting blade.