I had great lick with a technique I call "Cutie on a Leash." This is fine when you have three DDs or so ganging up on you. It stopped working with the laterst version of TMO, but should work with stock or RFB.
Fire a cutie out behind you with there is a DD looking for you in the general line. If the DD evades, when the cutie gets about 1800 yards away, give 30 seconds or so of full throttle, enough for the cutie to turn around and come toward you. Hopefully it will pass right over you.
Now, what's the most coveted piece of real estate for a DD hunting for a sub? That's right, he has to look for that overhead spot to drop his CARE Packages. Where's that nice slow Cutie returning to? What a coincidence!
Stand by for booms. Repeat as necessary. I've kept an active Cutie hunting for 20 minutes before. Hit probability, nearly 100%. Heh, heh, heh!