Best thing in the the world- setting up a 6 ship keel shot.
Find the one in the middle, use your gyro angle to send 'em after the others.
Holy crow, the carnage can get bad. If you do it right, you have 6 ships burning (or breaking

) all within 10 seconds of each other.
Drop a decoy, and follow your shots in under the layer.
Change course to match mean course of the convoy.
Fox is in the henhouse, and the dogs are having no luck finding you.
Once you're done reloading a couple of tubes, come to silent run, and drift up to take a peek.
Finish off the old kills with the stern tubes, generate new kills with the bows.
Rinse, repeat