The first week of August brings one of the most popular and famous water events to Seattle, the Seafair Hydroplane Races. The “thunderboats,” so-called because early racers installed booming engines from World War II-era fighter planes, use Stan Sayres Memorial Pits on Lake Washington as their staging area, as nearly a quarter million people watch from shore and boats on the lake. The pits were named after a pioneer hydroplane racer, who brought the sport’s leading trophy, the Gold Cup, to the area.
The pits sit at the head of Wetmore Slough near the site of temporary Duwamish Indian camps before the arrival of Anglo-European settlers. Pioneers recognized the area’s potential as a maritime hub, and an early scheme to build a canal from Lake Washington to Puget Sound included Wetmore Slough. (The canal was later built to the north.) The immediate area went through several transformations, although by the early 1960s, it had deteriorated into a garbage dump. After establishing the pits in 1957, the city redeveloped the dump into a public park. Visitors are allowed to walk the pit area, though during the days leading up to the race and race day itself, special passes are required.