Most of the time my tactics work.
I'll launch 4 separate torpedoes at 4 separate ships. My trick is that I aim them slightly farther aft
so that they impact the engine room and cripple the ship. I then dive to 175m, reload all tubes,
come back to periscope depth and fire at 4 more ships. Once I get about a dozen disabled enemy ships,
or the destroyer escorts have found out where I am, I go back deep and wait for the convoy to depart.
Then, depending on whether or not the ships I disabled are armed, I will either suface and shell them,
or just put another torpedo into them and watch them go down.
Also, any destroyer escorts that attempt to approach from the rear usually earn a Zaunkonig torpedo
that normally sinks them.
Convoy Attack Priorities:
1)Passenger Liners
2)Tankers
3)Troop Transports
4)Misc. Cargo Ships
And on the rare occasion that I find a convoy with a cruiser or battleship in the center, it usually gets my sole
opening salvo.