World Speed Record Attempt 
Sayres Sets World Speed Boat Mark With Slo-Mo-Shun IV 
Achieves Average of 160.3235 M.P.H.
Sayres Tops Campbell Record on Spectacular Runs in Seattle-Built Craft
First Mile in 163.785
Clocking Hit in Sanctioned Trial on Lake Washington – Gold Cup Bid Planned
Seattle, June 26  (AP) — Stanley S. Sayres whipped his 1,500-horsepower Slo-Mo-Shun IV over Lake Washington at a spectacular 160-plus miles an hour today for a newworld speed-boat record.
His rakish-looking hydroplane whined twice over a measured mile course at a pace nearly 19 miles an hour over the British-held former record. The former mark of 141.74 miles, set by Sir Malcolm Campbell's Bluebird II on Lake Coniston, England, has stood for eleven years.
Stymied last week by windy weather, automobile-dealer Sayres brought the Seattle-built racer out at 7:10 a.m. to take advantage of the morning calm.
The lake surface was rippled slightly, just enough to give Slo-mo-shun proper "footing." The speedboat, named at a joking suggestion of Sayres' wife, left a high plume of spray but little wake as it skimmed the first mile in 21.98 seconds — 163.785 miles an hour.
Confirmation 'a Formality'
Refueling in just half the 15-minute time limit set by international speed-trial rules, he ran the mile course from the opposite direction in 22.95 seconds, or 156.862 miles.
Kent Hitchcock, referee representing the American Power Boat Association, announced the combined average was 160.3235 miles an hour. The record time is subject to official confirmation by the International Motorboat Union but Hitchcock said this "would be pretty much a formality."
The speed run, held so early there were virtually no spectators made the former North American and United States records look slow. The former — 138.645 miles an hour — was set in 1949 by Harold Wilson at Picton, Ont. The United States mark of 127.063 miles was made by Dan Arena in 1949 at Gull Lake, Mich.
Ted Jones, designer of the Slo-mo-shun, rode with Sayres in the record-breaking performance.
Sayres said he was "very pleased" at the boat's performance and will enter it in major competition. His first goal is the Gold Cup races in Detroit next month.
Hinges on Boat's Showing
The boat's showing there will determine whether it will be entered in the international Harmsworth Trophy competition at Detroit in September.
Sayres said he has decided against any additional time trials. "We don't want to press our luck. The boat's next trip will be the Gold Cup races."
Jones added, "We know the boat has a lot more power. No further comment."
The record-smashing attempts started last Wednesday.
The first real try Friday ended when Slo-mo-shun lost a propeller and broke a shaft shortly after entering the measured mile. Hitchcock granted a four-day extension to finish the tests.
Sayres had remained "mum" on his boat's capabilities during months of testing on Lake Washington.
The Slo-mo-shun is a 28-foot craft powered by a 12-cylinder aircraft engine. A step-up gear boosts the propeller rate.
(Associated Press, June 26, 1950)