Harbor Raid noob question + cool story

[DuckHunter26]

Hey everyone,

28th december, 1940.

So i am in my 6th patrol, and after sinking two puny trawlers extreme bad weather sets in, the worst you can get (heavy rain, fog, 15 m/hr winds, the whole shabang). So i fiddle around and travel all around ireland, then back up the north sea and close to the english channel until i notice i barely have enough fuel to make it back to Kiel. Not wanting to face humiliation towards my comrades at base with 5000 tons, i take a decision. After opening Nav map, i zoom in and pick the closest port. Someplace called Southend, and herr Kaleun set out to raid it.

Long story short, after a long silent run in shallow waters, in a stormy night, i finally get within 5500 meters of the port. I wait until early morning for more light, because i cant see squat, and i see the outlines of a huge ship before me in the morning sun. Uber Troop transport, 25000 tons just sitting there, along with a few cargos and and destroyers. I set all my torps to hit under, but they all explode prematurely around the same spot. I figure there must be a net or something, so i set them at minimum dept and figured what the hell? and sure enough, it worked. Boom. There goes morning breakfast for the tommies waiting to be shipped off. And leaving i fired the stern tube at a parked destroyer just as a goodbye gift.

Then it was a silent run zig-zag between warships to get out at a nerve racking 15m max depth, poor hydrophone dude was probly going bonkers.

Anyway, as a noob it was a hell of a good time experiencing this for a first time. But now.. i want more muhaha.

Now, sorry for the long intro, noob question time.

I am having a hard time finding info about ports, or harbors, and strategy/techniques to go at them. Also there is a in-game map on certain harbors for mines and nets, but is there a map for the others?

Any hints/tips/pointers are welcome!

p.s sorry for weak english, french is my main language