Asterion operated off Cape Hatteras , North Carolina , on 14 April .
Asterion rescued the 55 men of the crew of a British merchantman that had been torpedoed earlier -- saving even the captain 's dog .
Operating off Cape Hatteras , North Carolina , on 14 April , Asterion rescued the 55 men of the crew of a British merchantman that had been torpedoed earlier -- saving even the captain 's dog .