but how about introducing submarines?
they were mainly surface vessels as the batteries afforded them little time underwater right?
if its impossible to render objects under the surface of the water why not make just the periscope visible in a dive but the whole ship when its surfaced?
or perhaps those small 2 man subs that entered harbours?
we could then add sub pens (new targets) and perhaps after a fleet is respawned they are forced to stay in harbour ports for 10 minutes and thus affording us time to attack them with subs.we really wouldnt need to see the subs just have an indicator for the player in control of them for where they are?.once the bomb is placed you escape.
The PTs and destroyers could have depth charges or we could have a seperate fleet for sub hunting.

I just thought it could be done because the LVs seem to be able to do the partly submerged thing so why not subs?