Anti-Submarine wessels/helicopters?

What about some Anti-Submarine wessels/Sonar helicopters patrolling the sea near the coast of your country, looking for submarines.

In peacetime, plotting them into a map
In wartime, search, attack and sink

I know, not all countries have a coast, but it could be a cool feature

Destroyers are anti-sub.

We will get right on it!

Hi Len, i run a Bill an Mil, on White Giant.
that's a military Contractor. i am in saveing
for a standalone Business School.

Frigates can also hunt subs. But destroyers main purpose in life is to try to hunt subs.