Mines in chute.
This is the remains of one of the 18 mines carried by UC-42 on her last mission, still sitting in her launching chute. The mine casing has corroded leaving just the white explosive materials. (Photo courtesy Timmy Carey, Blackwater SAC, Fermoy)
The submarine had 6 tubes to carry 3 mines each. Divers should be very aware that the explosive substance is still considered live.