100 subs sounds fine but as in 1943 the allied started new tactics and weapons ( hedgehog, some sorta seeking missiles )the U-boot losses greatly increased like for the month of May 1943:

"Monthly Loss Summary
- 40 British, Allied and neutral ships of 204,000 tons in the Atlantic from all causes
- 37 German and 1 Italian U-boats. In addition to those lost in or around the convoy battles: 3 by RAF in North Atlantic; 6 by RAF and RAAF Bay of Biscay patrols; 4 by US forces in the North Atlantic, off Florida and Brazil; 2 by collision in the North Atlantic."

100 boats with normal battle activitty would be lost in 2-3 three months...

I guess this was the moment Dönitz said "The battle of Atlantic is lost !"

I´ll have the names of the allied weapons for this achievement elsewhere but I´ll be back on those.

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