Just as a note, but larger ships tend to do badly against submarines. Especially without a sonar system. The engine noise allows the submarine to target it from a rather long distance, it makes a big hulking target, and doesn't have the speed nor the maneuvrability to pursue. (After all, a depth charge only works when the submarine is under the attacking ship.)
Now, onward with my own suggestion. Depth charge detonation can be fixed in a variety of ways. By adding a parachute, for example. That would defeat the purpose of airdropable depthcharges however. I think we should therefore switch to timedetonated depthcharges, rather than pressure based ones. It's safer(a nearby explosion won't cause them to go off), a bit more versatile, and still just as accurate(Things sink always at about the same speed. It should be fairly easy to set up a depth/time/altitude table). Also allows deeper explosions.
23. Timed Depth chargesSecondly, a destroyer is a lot of work, and not the optimal design against the thread we're facing. I therefore propose to focus work away from it. Ie, keep stuff theoretical for now. We will need to do major redesigns anyway, to make room for hydrophones and other antisub systems that would give it a chance of survival.
18.4 Keep Destroyer design theoretical (or in the fridge)And last for now, as a small suprise for our enemies. Let's take a couple of merchant ships, and equip them with anti subweaponry. They'll think twice before they attack a unguarded merchant again.
24. Develop Q-shipsStuff I vote for: 1.1/1.2 2 and 2.1, 6.1, 9, 13, 14, 15, 16, 18.4, 20, 23, 24.1. Fix Bomb Release and Depth Charge Detonation problems
1.1 Let the factory fix the bomb release
1.2 Bomber name: Wolverine
2. Electronics Engineer
2.1 Acoustic engineers
3. Recon plane camera
4. Fix the K-1, drop SPIA and MIAW
5. Finish the 14mm MG
5.1 Name: GVS-14
6. Scrap the monoplane, single engined biplane fighter
6.1 No, new monoplane
7. Upgrade popular devotion
8. Finish the diesel
9. Ship recovery equipment for the subs
10. Jet engines
11. Production of armored cars, 40mm mortars and depth charges
12. High-velocity 40mm
12.1 Finish projects
13. Small Rocket
14. Hedgehog
15. Take all and every engineer offered
16. Military academy
17. 320mm artillery
18. Destroyer
18.1 More AA
18.2 Drop double hull
18.3 Designate as cruiser
18.4 Theoretical design only
19. Complete BattleBus
20. Continue Airship
21. Diesel into Badgers, Hydras and PT boats
22. Quadlinked 4 autocannon
22.1 Not quadlinked
23. Timed depth charges
24. Q-ships