Welcome aboard mate.
You can go up against DDs and live to tell the tale but only under good circumstances. Namely dark nights and even better heavy weather or fog.
Early war set torpedoes as shallow as they can be set.
Sinking DDs is fun but you aren't going to make a very good living at it.
High risk, little reward and short career.
You are being paid to sink merchant shipping not DDs. I'd go with that.
I'm down there running deep and silent right beside Sailor Steve.
Magic