There were only three U-boats captured at sea during the war. The U-505 off of Africa, the U-110 south of Iceland in 1941, and the U-570, also captured off Iceland in 1941. The Brits got the latter two, scuttling the first after taking all the good stuff to preserve the secret of its capture. U-570 was recommissioned a British sub (HMS Graph), ran aground in 1944 and was broken up in 1961. The 505, of course, is on display in Chicago.
http://uboat.net/fates/losses/cause.htm