All you have to do is use an AI sub that does NOT conflict with the player's sub. Don't use any of the regular playable submarines. You're using v1.4 of the game, correct? I'm not sure if any of the mega-mods' AI subs would work in v1.4, but it's worth a try to make certain of the "testing". If it does work, then clone a playable sub following one of the tuts on that, of which I can't find a link for yet... keltos01 & Peabody did one, and I thought ETR3(SS) did one, as well as someone else, but I can't find any of them yet. s7rikeback has some files in his collection. I'll look there and see if I can find you a link...
