Putting the “Unlimited” into Hydroplanes

by 

Kirsten N. Johnson 

Gar Wood's great niece

When the calendar recently turned from 2019 to 2020, it marked the centurial of a truly epic year in speedboat racing history. 1920 was a year of speedboat glory for America, and for two men in particular. Gar Wood and Chris Smith - working out of a small boat shop in Algonac, Michigan - had now built the fastest speedboat in the world. With this boat, they had won the world’s supreme, Unlimited-class speedboat racing championship - the Harmsworth Trophy. The boat was the Miss America – a sleek hydroplane made of Philippine mahogany and driven by two converted 12-cylinder, 500 hp Liberty airplane powerplants.1

The powerplants that characterized “Unlimited” – the term used to describe a class of racing boats that have no restrictions on the displacement size of their piston engines – began a radical reformulation in 1918. Gar Wood, an auto mechanic turned newly-minted millionaire from his invention of the hydraulic hoist, was now indulging the boat-racing passion that he had developed in childhood. Outwardly personable and unassuming, Wood’s underlying fiercely competitive nature compelled his involvement in virtually every aspect of the design and building of his raceboats.

Applying the innovative thinking that had inspired his hoist invention, Wood saw a new potential solution to the problem of weight vs horsepower and speed. Marine engines were much heavier than the airplane engines of the…