The "chase down a CV" is pretty much impossible since your top speed surfaced is only 20 knots and the CV is at 33+.
I have to agree, WWII subs typically tried to attack from within 3,000 yds to realisticaly expect hits. Unless merchant shipping is added subs are not going to be utilised much. They WOULD add great targets for planes doing anti sub patrols and for PTs which ? if I recall already include (empty) Depth Charge Racks ? Depth charges should be easy, just slow down the rate of descent on a 500 lb ? Existing Radar programing could probably be adapted to SONAR for the destroyers? They'd have to add Negative Altitude to water squares. And keep the subs semi-visible to scouts at costal depths.
All in all an interesting idea, but ? I doubt it will get any priority from HT, given the OTHER options for additions.
