Stanley S. Sayres papers, 1950-2004

Stanley S. Sayres (1896-1956), the owner and driver of the Slo-mo-shun hydroplanes, moved to King County in 1932. He was in the automobile business and headed the American Automobile Company, a Chrysler car dealership at 1001 Broadway in Seattle, and an auto parts store in the University District. Sayres also owned the Jen-Cel-Lite Corporation, a manufacturer of cold weather clothes.

He became interested in speedboat racing in 1926 in Oregon, and his interest continued after he moved to King County, Washington. In 1949, Sayres built a 17-room home on the east side of Hunts Point near the point's north end (4450 Hunts Point Road), along with a boathouse for his hydroplanes. Hunts Point is on the east side of Lake Washington.

Sayres had owned and raced smaller boats, but he wanted to try for a world record. With this in mind, he commissioned Ted Jones to design the Slo-mo-shun IV and Jensen Motor Boat Company, at the north end of Seattle's Lake Union, to construct it. Jensen Motor Boat Company launched the 28-foot-long, 4,750-pound hydroplane in October 1949.

Sayres established a world speed record (160.3235 mph) for hydroplanes while driving the Slo-mo-shun IV on June 26, 1950. The Slo-mo-shun IV was King County's own: the owner, designer, builder, mechanics, and crew were all Seattle and King County residents. The only parts of the hydroplane not constructed in Seattle were a surplus World War II airplane engine and the boat's propeller.

(Information retrieved from Pacific Coast Architectural Database and History Link)