Royal Navy slang
dating back before the Second World
War, it means to defecate, crap, shit or take a dump. Nothing
fancy, to crimp off a length you merely have to evacuate your bowels.
"That fat fucker of a stoker is getting
shitty with me again!"
"What'
re you goin' to do?"
"Next time the cunt is down the engine room, I'll
crimp off a length in his best boots!"