With a very Big Stick !
Seriously tho, best results is achived by stealth with an electric (DD dont know your there) or Acustic Homing Torp (so long as the DD's between 10-23Knts, the A-torp speed is 24Knts). Last but not least T1 set for fast at close range with DD at speed (best when he's runing at you ahead or astern).