Favored mode of attack?

[HMCS]

So what is your favored method of attack? Surfaced/night? submerged?

My personal choice is dawn/dusk submerged: I can use both g7a's and e's at whatever range; it also allows me to identify neutrals vs. legit. targets.

I always try to penetrate the outer column, with a view to gaining the interesting targets in the center of the convoy.