 "Stanvac Calcutta" was a 10,170 ton tanker with a crew of forty-two merchant mariners and nine armed guards aboard.The ship was commanded by Gustav O. Karlsson and the guards by Ensign Edward L. Anderson.Throughout World War II merchant ships were lightly armed and out of the six to be attacked by German raiders, only "Stanvac Calcutta" and offered serious resistance and both were sunk.