two DDs v 1 DD (me) yet hydrophone says DEs any help on this one
If I remember right there is also a US sub hanging around.
I found my success came from targetting fire on one of the DD's whilst staying at a reasonable distance to not take too much damage.
Once one is finished off, re-target the second and repeat.
The challenge is to stay at a enough distance so your fire makes an impact on them whilst not taking too much damage. If you decide to slide in close use the opportunity to take (many many many) shots with your torps.
If you can do enough damage you may be lucky enough for that sub to help you out.