I have a location for you now!!! The place to hang out and go duck hunting ison the border line of BF12-13, a 1/3 of the way down from the top of the square.
It's there from June 1940 to end of 1942 (I think!:hmm
The liners are moving at a fair rate of knots (21 knts!!), but a torpedo or a couple deck gun rounds slow them down. To find the exact "sweet" spot where they going to pass submerge and do a sound check. Don't worry if you miss one, another will be along soon!
My record for coming home from here (with and IXB) was (wait for it!!) 300,000 tons!!!
Thats the truth!! I used a single torp shot (on mag settings) aiming under the second funnel. It took down about 65% with one shot
Happy hunting!!
Just as long as I'm not there, if so, find somewhere else please!!