http://www.subsim.com/radioroom/showthread.php?t=170528
1. War Material ships have tanks and vehicles on their decks. They also say "(War Supplies)" in their name, ie: Large Steamer (War Supplies)
2. Any in the general area should count.
3. Yes, but you probably won't find the war supplies ones on the east coast.
Refit = refuel and rearm without ending your patrol.
End Patrol = take some time off while in dock and get a new patrol objective as well as being able to upgrade items on your u-boat and reload with custom torpedo loadout and switch active missions if desired.
Depth Under Keel is part of the 1.2 patch UI: