(MB: t. 13; l. 60'; b. 10'; dr. 2' (mean); 8. 20 k.; cpl. 8; a. 1 .30-car. mg.)
The third Uncas a wooden-hulled motorboat built in 1917 by the Greenport Basin and Construction Co., of Greenport, Long Island, N.Y.—was acquired by the Navy from Charles L. Poor, of New York City, on 28 June 1917, for use during World War I as a section patrol boat. Assigned to the 3d Naval District and given the designation SP-689, the motorboat—operating without a name since a tug named Uncas was already on the Navy list—conducted local patrol operations out of Section Base No. 6 at Bath Beach, N.Y., for the duration of the war. She was returned to her owner on 31 December 1918.