destroyers are escort vessels for other ships.
destroyers are the logical counter to subs.
however they lack the sonar range to protect themselves most of the time.
a subs sonar range is large and so is their range they can sneak up on destroyers undetected until at launching distance and then turn and run away
the destroyer will barely have time to launch its shots in retaliation before it too must flee from the torpedoes.
1v1 combat the sub(if microed reasonably) will win 8 times out of ten