Got to hand it to you Hubert the changes to naval surprise makes using U-Boots a worth while exercise!
Just finished a game (using the default difficulty settings + FoW +USSR neutral) my U-Boot fleet was blasting the British convoys out of the water, between 20 - 40 MPPs per turn!
Normally I just throw my U-Boots into the fray as soon as I get them, usually get spotted and sunk within a couple of turns
This time I changed tactics and waited till the fall of Netherlands and France before using the points from them to build a fleet of 4 boats (had to wait two turns to get them all built in the French ports in between buying two more aircraft and an HQ 'Rommel') also sent the Kiel boat down the coast of France and out into the Atlantic. Had to repair it enroute though British and French fighters plus a British cruiser knocked it down to 2! It survived due to my airfleets all under control of HQs.
The first three boats were sent off to the coast of Canada (Original Atlantic boat plus the two French based ones) taking two turns to get into position. These were closely followed by the next two French based boats a turn later and the Kiel boat (now repaired) a turn after them.
The first group of three were positioned two hexes away from Canadian coast middle boat in line with Halifax with a boat two hexes above and below it. Took 23 MPPs. The original Atlantic boat took 7 the previous turn as it got into position early. This is probably why the British sent two cruisers out to investigate. Both were surprised by my boats knocking 1 and 2 points off for the loss of 2 and 3. My turn saw both cruisers being sunk both attacked by two U-Boots each. Lost between 3 and 4 points of damage off three of the boats with one receiving no damage at all!
The remaining two boats take up position two or three hexes east of the rest. Took 26 MPPs off Britain that turn.
The British response is to send a battleship and cruiser to break my blockade and get surprised by the two trailing boats and then viciously sunk by the other packs.
Britain did not send another ship into the mid Atlantic after this. I was able to keep 5 boats on station letting the 6th return to refit, then rotating this until they were all back up to 11.
While this battle for the Atlantic was taking place the Luftwaffe sunk a battleship that made the mistake of sailing down the English channel, destroyed 2 RAF units and the FAF!
The demo ended two turns after my U-Boots started taking 40 MPPs off of Britain. By this time all 6 boats were crowded within 4 hexes of Canada.
Donitz would have been proud.