I just revisited the US website, U-Boat Archive. I have not seen it for a while and I do not remember it having the wealth of info that it now has. The POW interrogation reports are a great source of many details that one could otherwise only learn by interviewing surviving U-boat crew members.
It's address is www.uboatarchive.net
Then click onto "Browse the Archives"
Then look for catagories that include "Interrogation of Survivors."
Then go towards the end of the interrogation reports, that's where you'll find the equipment and operational details.
Often in POW reports, if there is a discrepency with what a prisoner has said the report will include intelligence was found through earlier sources.
This site offers many crisp photos, mostly of U-boats getting clobbered. You will also find interesting ships histories plus lots of equipment and operational details. There is also an over-abundance of analyses of the US Navy's anti-sub actions. (Allied shipping was getting clobbered by the U-boats and the US was trying to improve the U-boat kill rates using every way and means possible) If you've been bitten by the U-boat bug POW reports are the way to go. (They were the best technical source of information on our Seehund German midget u-boot.