[John Pancoast]

Originally Posted by Jimbuna

Hi John if you'd asked me the other night on Discord I would have still had access to my reference materials but as is typical, I moved them into the loft this morning.

Sooooo iirc it was early to mid 44 when the Allies gained air supremacy which meant U-Boats could not stay surfaced long enough to charge their batteries, not to mention the long process of loading torpedoes.

For a more precise answer I'd suggest having a look over at https://uboat.net/

Thanks Jimbuna.