U-615
Ordered: 15 Aug 1940
Launched: 8 Feb 1942
Successes: 4 ships sunk for a total of 27,231 GRT
Fate: Sunk 7 Aug, 1943 in the Caribbean Sea south-east of Curaquo, in position 12.38N, 64.15W, by depth charges from US 6 Mariner and 1 Ventura aircraft. 4 dead and 43 survivors.
The boat was lost in this massive hunt in the Caribbean. It fought bravely for days against overwhelming odd before finally being sunk. This was possibly the longest ongoing combat between a U-boat and aircraft. U-615's battle enabled many other U-boats in the Caribbean to surface and escape to the east.
source:
http://www.uboat.net/boats/u615.htm