The SM U-111 was one of five German U-boats from World War I that were sunk in U.S. waters and it's the last to be rediscovered.
According to an exclusive report by National Geographic (link opens in new tab), a team of shipwreck hunters has discovered an extraordinary sunken vessel off the East Coast of the United States: the wreck of a World War I German U-boat sunk by U.S. warplanes a century ago for target practice.
Commissioned by the German Imperial Navy in 1917, the 235-foot U-111 patrolled the waters of the North Atlantic, sinking three Allied merchant ships before the Kaiser’s surrender in November 1918.
After Germany agreed to the armistice in 1918, all seaworthy U-boats were sent to the British North Sea port of Harwich, where most were cut up for scrap. However, a handful of the early submarines were sent to the U.S. to be studied and reverse-engineered; and the U-111 arrived at Portland, Maine on 18 April 1919.
Sunk on purpose
By early September 1919, the U-111 had completed a head-to-head comparison test against the American submarine USS S-3 (SS-107). In 1922, the U.S. Navy deliberately sank the vessel, but its exact location was not disclosed.
The U-111 was sunk on 31 August 1922 when her hatches were opened, and the USS Falcon set off a depth charge by the sub. When the U-boat sank, the U.S. Navy thought the seawater at the location was much deeper, and that the vessel would sink to the seafloor at a depth of about 500 m (1,600 feet).
In fact, the wreck rests approximately 120 metres (400 feet) below the ocean surface near the Winter Quarters Shoal lightship along the Virginia coast.