Many books have been written on the topic, for example, when last checked, Amazon UK had 7,546 books listed that were linked to the U-Boat.
Not all of the information that is written about U-boats however, is 100% accurate. From reading some of the information, it appears that some U-Boats were in two places at the same time, or a U-Boat sank a British ship quite some after after it was itself sunk.
It would take years of research to get fully accurate facts on this subject.
But all the same, it all makes very interesting reading. I grew up with model Spitfires and Hurricanes hanging from my ceiling , and model Battleships on any flat surfaces in my bedroom. But now, for some reason, at a much older age, I have become curious about something that I knew little about when I was young.
One thing that I cannot fully understand is why the Germans, when numbering the U-boats, re-used the same numbers from previous U-boats. For example: U-Boat 99 was launched in 1917 and in 1940.
Then there are the missing U-Boat numbers. For example, the highest numbered WW1 U-Boat appears to be U167, but there are 22 missing numbers, as far as I can tell: (U42, U115, U116, U121, U127, U128, U129, U130, U131, U132, U133, U134, U143, U144, U145, U146, U147, U148, U149, U150, U158, U159)
In WW2, the highest numbered U-Boat appears to be U4712, but with only 1,153 U-Boats listed, that leaves 3,559 unused numbers, and I don’t think I will list that many here 🙂
42.1 - 624,469