The dit I heard was that one of the lads bought an all singing, all dancing mega expensive bike at a great price in a PX on some US Navy base. As the boat was in AMP, the main access hatch rim had been removed, which meant he could get the bike (wheels) into the boat. The bike was then dismantled and carefully stashed away.
The purchaser knew that he (nor anyone else!) would be able to get the bike off the boat until arrival in the UK and the main access hatch rim was again removed.
However, this being the submarine service, nothing should be taken for granted....... Once at sea, his 'friends' got bored, as you do. So the story goes that they decided to cut the bike into bits and pop them into the gash compactor.
Back alongside in the UK, the luckless purchaser seemingly searched the boat high and low, as it couldn' t have gone anywhere - could it....?
I do hope this is a true dit, or even based on truth, as shows sheer genius!