We think alike sometimes CB, I too wondered about the same thing. I didn't realise the ships didn't fire torps, but may be that can be changed by adding some of the sub parameters in to the ships parameters then IF it works then you may be half way to changing the sub's AI.
I believe the AI subs fire the deck gun, perhaps the deck gun an AI subs could be made more powerful to compensate no torpedoes, just a thought.
I did have quick play with AI subs, one thing they did do was draw a bit of fire away from the player sub, giving me a better chance of a decent shot.
