Action of 4 April 1918

The Action of 4 April 1918 was a naval action fought somewhere in the Atlantic Ocean during World War I. An unidentified Kaiserliche Marine U-boat attacked three armed transports of the United States Army and Navy, but failed to damage the American ships before she was sunk.

Action
On April 4, 1918, three armed transports, USAT USAT Henry R. Mallory, USAT Tenadores and USS Mercury (ID-3012) were steaming back to the United States in convoy after having completed a troop transportation voyage to France. At 11:45 in the morning, a German U-boat of unknown designation surfaced and fired torpedoes at Mallory. Lookouts aboard the transport spotted the torpedoes, allowing the ship to successfully evade them.

The submarine was sighted by the other American transports; all three ships opened fire with their main guns, and appeared to hit the U-boat as she submerged. The vessels then maneuvered in close and depth charged the last-known location of the Germans. The three American vessels were credited with sinking the attacking submarine. The convoy reached the United States on or about April 13, 1918.