http://www.uboataces.com/ref-insignia.shtml
Over 4,000 U-boat numbers are in the bottom's database. Say your U-boat number is U-246. Just go to the bottom and select the range that it would be found in. Scroll through to learn details about your U-boat AND its fate. Besides this, the emblems can be found there. They aren't in color, but you can still use them in game after a bit of tweaking.
Happy hunting.
EDIT:
My U-Boat:
U-93 - Type VIIC
Commissioned: Jul 30 1940
Fate: Sunk
Date: Jan 15 1942