Convoy attack tactics in SH3 vs. tactics of real life U-boats.

[Agiel7]

I've read that most U-boats conducted torpedo attacks during the night while surfaced, since the Allies' ASDIC wasn't as effective on surfaced boats. However, I've never used this tactic since the Brit's destroyer crews have been eating their carrots. I'm not sure if this tactic was properly modeled into the game, so have any of you tried it?