This Spanish site has a very detailed virtual tour of
U-995, along with a number of plans and diagrams created especially for the site:
http://www.u-historia.com/uhistoria/.../intecnico.htm
This is
U-570's "Design and Specification Book, Volume M," partially translated to English. Lots of plans and diagrams that I didn't even know existed!
http://www.uboatarchive.net/U-570DesignBook.htm
Now, when are they going to make an updated edition of the Type VII book in the "Anatomy of the Ship" series?