[PavelKirilovich]

I'm all for that. I've got reams of experience sneaking into harbours, even late war - Hartlepool in December of 1944, for example. For some odd reason most people seem to find this challenging.

One technique that requires a bit of testicular fortitude is to wait for the DD, DDE, Angry Fishmonger's Wife, whatever really, to start its attack run on you. At that point punch the engines ahead to Ahead Flank if they're not already there and turn in towards the attacking warship, to the point that you're basically looking for a head-on collision. Take her down as low as you like, though I generally pull this off at 20-25m so I can quickly come back up to periscope depth to engage targets if I have to.

You have three major worries once you've done this. Forwards, the worry are hedgehog launchers, to either flank you're worried about the wabo launchers that chuck them a decent ways off the side of the vessel, and aft you've got your traditional racks to worry about. Coming in hard and fast on the ASW boat - that is also making maximum rotations for flank speed, so generally 25-30 knots - destroys their datum for side-launching wabos. They might give you a taste of hedgehog, but if you're going quick enough you'll be nosing underneath them by the time those hit water's surface and start on their way down. It's a bit like a mortar, that high "hang time" in the air gives you a few moments to react.

Once you're in close like that, kick out a Kobold and execute a hard port/starboard turn, run for ten seconds at flank, and cut it back to silent running. Make another hard turn to keep you well inside the ASW vessel's baffles and go deep if you can. If not hug the bottom and be patient.

I find I can generally break contact with everything short of Heimdallr himself using this method, as risky as it is. I'm also not running GWX at the moment, so it's far less suicidal for me to try this trick than anyone who is running GWX.