The hydrofoil, a boat supported clear of the water by underwater wings called hydrofoils, was invented by an Italian, Forlanini, in 1898. In 1918 a hydrofoil, powered by an aircraft engine, gained the world’s water speed record. The commercial hydrofoils now used in Europe are based on the work of German engineers who carried out research into the design of high-power, lightweight engines.
In the early 1950s hydrofoils were developed in the United States, Canada and Russia using high-powered gas turbines. They are used for both military and commercial purposes.
Since water is 775 times heavier than air, very small hydrofoil wings will support relatively heavy boats. But, since operating in water puts great loads on boats, the hulls are usually built of high-strength steel.
The object in raising the hull of the hydrofoil from the water is to avoid the resistance caused by friction and drag. This means the power needed to drive the boat at high speeds is cut by half. Another result is that the hydrofoil travels smoothly in quite rough water, and is not slowed down.
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