Convoy kills - do you confirm them?

[MarkShot]

I suppose this should be a poll, but I've never made one before. So, for convoy attacks do you:

(1) Confirm kill - see the torpedo strike from the scope or bridge?

(2) Confirm kill - see the target sink?

(3) Confirm kill - simulate surfacing later and examining the debris field?

(4) Disengage/evade - immediately after the last tube is empty?

I ask, because conventional wisdom in these games has been that #4 lead to the greatest chance of survival. However, from the few sub documentaries/books I have read, confirming kills was important and done.

Thanks.

PS: It would be a first for a sub game to actually require confirming sinkings before crediting them.