Submarine escape training as a test of pressure and nerve

Richard Humphreys describes the final stage of submarine training at the hundred-foot escape tank on the Gosport side of Portsmouth Harbour. The account acknowledges that trainees had died there and describes the fear before entering. A pressure chamber first tested whether his ears could tolerate conditions equivalent to one hundred feet of water, with rising temperature during compression and cooling as pressure fell. Four ascents followed: two free ascents from thirty feet, one from sixty feet, and a final ascent from one hundred feet in a pressurised suit through a cramped escape hatch. His remembered childhood fear of water made the experience particularly daunting. The later commentary explains that pressure, disorientation, and confinement helped make training psychologically close to escape from a stricken submarine.