Former names retained.
(SP-4.212: t 23; l. 62'4"; b. 10'11"; dr. 2'6"; s. 21 k.; a. 1 1-pdr.)
The third Inca was a motor boat, built in 1917 by Herreshoff Manufacturing Co., Bristol, R.I.; and acquired by the Navy from her owner, F. B. McQuesten of Boston. She commissioned 28 July 1917 at Boston, Ensign R. B. Fuller, USNRF, in command.
A versatile craft, Inca was first assigned to the First Naval District and patrolled outer Boston Harbor. She also performed coast convoy duties with submarines during this period, and acted as test ship for submarine signalling and detector devices. She was reassigned to Fifth Naval District in October 1917 and arrived Hampton Roads 3 November. Inca's job was to serve as rescue ship for aircraft from the Naval Air Station on flights over the Chesapeake Bay and Potomac River. She also served as a seaplane tender during 1918, and spent time on harbor patrol in Hampton Roads. Inca was assigned 26 July 1918 to the Industrial Department, Hampton Roads, as a dispatch boat, and remained on this duty until returned to her owner 17 April 1919.