How do Destroyers kill Subs

[Titan]

Each time i try and attack Subs with destroyers i get the "to close to land" Destroyers seem unable to attack and kill subs

[AlbertN]

Surface ships cannot attack Submarines.
Only air units and carriers can.
Submarines can attack surface ships though or intercept them (They lurk!)

Otherwise the job has to be done by your Escorts that you assign to convoys (and that you can tech up with the appropriate technology).

[Titan]

If my WW2 knowledge serves me correctly i thought Destroyers were the biggest threat to subs? I'm a little bewildered why they have no Anti sub ability? I cant recall reading about HMS Glorius or any other British carrier chasing subs around the ocean..hard to imagine Fairy swordfish being everyday sub killers. Does not sound right to me

[AlbertN]

That is represented by the Escorts you put along convoys lanes.
Otherwise submarines would be dead in 2 turns if regular Surface Ships can find them.

See the naval units as proper big ships with some destroyers attached as their own escort against submarines or so - and sub hunting stuff are escorts.
In the end no naval unit was chasing submarines around. Naval escorts were around convoys, and locally chased submarines -after- the submarines were spotted / detected.

[AlvaroSousa]

Only CV/air can attack subs when they are surrounded by all ocean hexes.

An air unit can catch a sub on the surface and go after it. A ship can't. The sub will spot the ship and dive. By the time the ship gets there it can't find the sub.

Escorts protect convoy lanes in the convoys section.