ciancoloni

I suggest to add an antisom group on aircraft carriers tier VII or higher because we had embarked antisom starting from a dedicated version of Avengers

Another issue abot realism for subs is the use of sonar. Sonar is an active device having a problem witj its use. If you use active pinging you have a very good landscape of target and tactical situation, but you show yjw enemy a clear picture of yourself. So, this is why subs use hydrophonic research and, due to this fact, I suggest you to give subs also the hydrophonic research, at least as a consumable, like surface vessels

Subs may have more realistic operational scenarios. You may think about invertion layers (salinity and water temperature) according to depth. So you can allow commanders to avoid detection using these layers at the best; you may think about night scenarios allowing use of smokestack ship trace. This might allow a sub to navigate in surface with an higher speed maybe necessary a tutorial about subs commands and options

Beware, don't use autopilot between islands with narrow chokes because it's easy to collide against ground