USS Alert (SP-511)

USS Alert (SP-511) was a United States Navy patrol vessel in commission from 1917 to 1919.

Originally the civilian motorboat Alert, she was built in 1916 by the Matthews Boat Company at Port Clinton, Ohio. The U.S. Navy acquired her from her owner, J. K. Newman, on May 10, 1917, for use as a section patrol vessel during World War I. She was commissioned as USS Alert (SP-511) on May 22, 1917.

Assigned to the 9th Naval District, Alert performed patrol duties on the Great Lakes for the duration of World War I.

Following the end of the war, Alert was stricken from the Navy List on April 2, 1919, and sold on June 16, 1919. Her subsequent fate is unknown.