well, if the damage model is good (actualy it is, but this cant be done anyway) then i should have had a IIC instead of a VIIC on my last patrol, damn merchant refused to sink, was out of torpedos and weather was to bad for the gun... sollution ? INDEED! i rammed it
unfortunatly it didnt work so well and i lost half the boat's hull %, merchant ? was still floating arround
eventualy waited 2 days for the weather to clear up, surfaced and spend 80 shells in the bugger (he was dead after 5 but what the heck... was angry at it)