File:Coolidge Propeller Co employees posing with large propeller, Seattle, 1911 (MOHAI 11137).jpg

Seattle's Coolidge Propeller Company was begun by Leigh Hill Coolidge (1870-1959), a prolific naval architect and pioneer in the design and machining of high-speed propellers for racing hydroplanes. One of the most well-known vessels he designed is the City Light excursion vessel Alice Ross, which gave its first tour of the Skagit River Hydroelectric Project on Diablo Lake in 1935. As of 2018, City Light still offers tours of Diablo Dam on the Alice Ross IV. In this image 20 men stand together at the Coolidge Propeller Company, posing with what at the time was the largest bronze propeller ever cast. The propeller weighed almost a ton and was fitted with blades which were made to change their positions by pneumatic pressure, using the angle of the blades to drive the vessel either forwards or backwards. The propeller was designed by Mr. Coolidge for the refitting of the barkentine "Archer" into a power boat. The "Archer" was built in Sunderland, England in 1876, and held the sailing record between Puget Sound and San Francisco.

Caption information source: The Seattle Daily Times, April 15, 1911, p. 8; and January 12, 1959, p. 29.

• Subjects (LCTGM): Boat & ship industry--Washington (State)--Seattle; Coolidge Propeller Company; Group portraits; Vessel components--American--Washington (State)--Seattle