Otto Lehman

Otto Lehman was the captain of a sinking IXD2 U-Boat on 14 September 1944, during the Battle of the Atlantic. The Tenth Doctor was able to gain his trust and wanted to save the crew of the U-Boat, but Heather was reluctant because they were Nazis.

The Doctor was able to convince her otherwise by arguing that the crew had just as much a right to live as any other humans and that even after repairing the U-Boat's damage it was highly unlikely that the U-Boat would be able to rejoin with German forces. Heather and the Doctor left the U-Boat after the leak was fixed, leaving it to be captured by the HMS Worthy. (COMIC: The Submariners)