[Fincuan]

Originally Posted by Kromus

http://www.uboat.net/types/ixd.htm

Look for facts first.

Depends entirely on which "facts" one chooses(tens of site on the internet saying different things), and which type IXD boat we're talking about. The range you listed matches quite well the range of a type IX/D1-uboat in kilometers, while that of a type IX/D2 was supposedly considerably longer, over 30,000 nm.