I once did a torpedo run on a pair of transports, including a liner.
After using external camera to observe the fireworks, I took note that of three torpedo hits on the big one in front, but there was only on visible hole in the ship. There was lots of fireworks also.
Needless to say, one of the life boats was apparently in a bad place when torpedo 3 hit, and got caught in the blast, because 'life boat' showed up in my log right after 'huge european liner'.
I didn't notice it until my patrol report showed I had sunk 4 ships when I had only sunk 3 by that time, causing me to check my logs and notice 'life boat' listed.
As for shooting life boats... waste of ammo...
Let them be rescued and become a waste of enemy time, resources and medical supplies. To easy to bury the dead.
So being humane (sort of) in a war in itself becomes an attack on enemy logistics.
