Recorded with Fraps.

Didn't see any video on Youtube doing this, so here.

Tips:
-Two torps to sink a destroyer or cargo ship
-Recommended distance for head/rear-on charge against destroyers: 0.2
-Play peek-a-boo with the sail to refill air without exposing the whole sub
-Go depth 4 if PTs get too close until they are a decent distance away.
-Don't bother trying to sink the PTs, it's possible but will cost quite a bit of health and doing so will simply spawn some depth charge armed seaplanes.

Original strategy: http://strategywiki.org/wiki/Battlestations:_Midway/Crucial_Cargo