USS War Bug (SP-1795) was a motorboat in commission in the United States Navy as a patrol vessel from 1917 to 1918.

War Bug was built as the wooden-hulled motorboat Herreshoff 320 at Bristol, Rhode Island, in 1917 by the Herreshoff Manufacturing Company for a private owner, and probably was designed with possible naval service in mind.

The U.S. Navy purchased Herreshoff 320 from Felix Warburg of New York City on 6 November 1917 for use as a patrol vessel in World War I.

However, this proposed movement appears to have been cancelled, probably because of the armistice with Germany of 11 November 1918 that ended World War I and eliminated the need for more U.S. Navy patrol craft in Europe.

Decommissioned on 28 December 1918, War Bug was sold on 30 June 1919 to E. Atkins and Co., of Boston.