Hey Wolfram,
I usually follow the same protocol but when I've expended all my torpedos, it's time to bring out the deckgun crew.
I just can't stand to watch them steam away from me without attempting to sink or cripple a few more.
I usually try to engage them from 3500m to 5000m during daylight to lessen the pelting I get from multiple ships firing on me. I also try to attack them from the end that doesn't bristle with heavy guns. And now with the Leigh light mod, it makes it harder to shell them at night looking into the glare of all those searchlights and trying to be inconspicous. No chance.
I still don't see any effect of having or not having a medic on board. None of my wounded ever die on the way home from their wounds. But they definitely earn each and every wounded badge for obeying my sadistic wishes, hehe.