Did Allied submarines leave Malta at night, and how quickly could they submerge?
Short answerThey could submerge quickly and tended to remain underwater in harbour during daylight to avoid detection by bombers. No precise diving time is given.
NotesSubmarines remaining in Malta during the day tended to submerge in harbour so bombers could not spot them. Grand Harbour provided concealment while the boats waited to operate. They could submerge quickly, although no precise diving time is given.