Well lets say you are in bad shape. Your air is FUBAR and the DD is making another run.
Keep your sound profile to a minimum by presenting your arse to his bearing. Come up to 25 meters. Under 2 knots silent running.
Thats right its going to get hairy
Set four forward tubes to contact and shallow. Make sure tdc is clear. no last bearings no position keeper and open the tubes!
Sound battle stations. (maximum crew reaction)
Follow nearest target with sonar.
Put the scope up at minimum zoom at 000. (more hairyness as thats just below destroyer draft.)
Set gun crew to fire at will and target weapons.(only if you have forward firing deck gun. Dont be a pussy!)
When the bearing changes rapidly thats when he is right over your head.
Ie: pinging crazy map showing rapid change in bearing.
Order back emergancy!
Emergency surface!
Watch the gun icon. once it has signaled manned, man the foward AA yourself(not the deck gun) and aim at the depth charges!
Poof!
bye bye destroyer.
now in case it does not work then fire a spread with no bearings at left 2 right 2 left 5 right 5.
PS at slow speed.
This only works if one DD is on top o you.