…I did see a film on TV a while ago which showed literally dozens of crated jeeps being shoved off a ship into the sea at the end of the war, and it didn’t look like they were out at sea but in a harbour of sorts…

Not trying to disparage you, this programme or the event (if it happened as described), and stating the right bleedin’ obvious but you just don’t dump stuff in a harbour you might even remotely use again! Quite apart from actually blocking the waterway anyone who falls over the side could be injured, or worse.