I didn't need to see the deadliest catch myth to know you can get yanked overboard by a spool of rope.
My cousin is a lobster fisherman in Nova Scotia and got pulled overboard when he got tangled up in the rope. He was pulled under by the weight of all the lobster pots and they had to winch everything back up to get him out. He wasn't breathing when they pulled him out and only came back after my Uncle performed CPR on him. He was very lucky.