Im not really sure if this is true for other people, but in all of my games not many people have used subs. That was with extensive patrolling of the oceans in most of those games. Im not sure if maybe its the damage or costs. I think its because its kind of hard to hide them. Playing as the us It is very easy to get a couple destroyers, Naval patrol aircraft, or even ASW choppers at the main ocean junctions and bam, no subs go your way with out being seen. My idea would be some kind of noise detection. There is sonar already but that is more of an active sonar since that behaves more like radar. Realistically Active sonar would give your position away to what ever your are trying to detect, thats where passive sonar comes in. Sonar equipped vessels (helis and planes should keep the active) should have a choice between switching the two. Ships and subs in rush mode should be easily detected, subs moving normally but for a long distance have medium, and short burst a slightly less chance, and a stopped sub even smaller. The chances of passive sonar detection should rise as you get closer the ship (say as a sub moves closer to a destroyer.) Passive sonar gives both subs and ships a more stealthy approach, and if they switch to active it works like radar but gives their position away to other sonar equipped vessels. This system would give subs the chance to be more stealthy but at the cost of a more careful gameplay, but if the player wants to detect everything, but with no stealth they will have that choice. Im not sure if that is even possible to code that or something similar, but it was an idea.

Please put your ideas down below

Ok thanks for the tip with the frigate. I also did not know that destroyers were supposed to be mainly ASW. I thought they were just cheaper all around ships, and noramlly used them as my main filler ship