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!"
"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!"
by AKACroatalin April 10, 2015
I had such a massive turd this morning, i had to crimp off a length to stop it rising too high in the bowl
by Doctor rotcod February 25, 2014
by SusieQ October 4, 2005