To answer a question, dinghies, and lifejackets were, and possibly still are, mandatory when flying in a slow aircraft, Chipmunk, Bulldog etc, within five miles of any large expanse of open water but were often carried anyway because most of the location and survival aids were useful on dry land as well as water. Bit difficult to use flourescine and solar stills in forest but flares, SARAH, SARBE, heliograph etc worked well anywhere.

ROcketeer should have said that when the PSP is released it doesn’t free fall but remains attached and dangles by another cord/tape, the length determines how soon it splashes before the person it’s attached to and gives them time to assume the position.