The SMS Cap Trafalgar sailed a peaceful trade line between Germany and South America. At the start of WWI, the ship was requisitioned by the German navy.
Captain Wirth (Julius Wirth, pictured below) was brought on as the new commander, and the ship was charged with the mission to sink British merchants.
The ship was anchored at Trinity, a small volcanic island being used as a German rendezvous point. In order to blend in, the crew, numbering around 300 men, disguised the ship as a British ocean liner, the RMS Carmania. The ship was outfitted with new guns, and they set sail for Brazil.
Five days into their voyage they received a radio transmission. Crefeld, the ship that was originally supposed to refuel the SMS Cap Trafalgar off the East coast of Brazil, had been reassigned to instead refuel a different German ship. Coal was scarce among the entire German navy at the time, and so with nowhere else to refuel, Captain Wirth turned the ship back to Trinity, arriving just two weeks after leaving, without having run into a single enemy ship.
Once loaded up with fuel again, they set sail, searching for British merchants to ambush in disguise. As luck would have it, they did run into a British vessel: a cruiser that had been requisitioned by the British navy and outfitted for war with heavy armaments. To Captain Wirth’s surprise, however, this ship turned out to be the real RMS Carmania, the ship theirs was disguised as. The RMS Carmania opened fire and within an hour the SMS Cap Trafalgar was sunk.
The survivors were rescued from the water, but of the 300 crew, 16 had drowned in the sinking. Among them was Captain Wirth.