I don’t know the identity. But in 1969, I and a few other Peace Corps members, we’re drinking beer on the beach at Freetown. The sun was setting low on the horizon and it must have been a low tide. I spotted what I will swear was the conning tower of a uboat sitting off in the distance. The others wouldn’t buy it but begrudgingly admitted it looked like a sub but it must just be a rock.
Years later, I read that a Uboat attempted to enter the harbor where convoys typicality resuplied/took shelter. Because of bad maps and timing of tides it got stuck on a reef. They had t surrender to the Brits the next day