The Hydroptère is an experimental sailing hydrofoil designed by the French sailor Alain Thébault. Its multihull hydrofoil design allows the sail-powered vessel to reach high speeds on water. The design is based on experience from a range of hydrofoil sailcraft that Thébault built in cooperation with the late Eric Tabarly since the 1990s.
On 2008-10-05 the Hydroptère attained a record speed of 52.86 knots, however this was over a shorter distance than the 500m necessary to qualify for an official world record. On December 21, 2008, lHydroptère briefly attained a speed of 61+ knots, but capsized shortly thereafter.
On September 4, 2009, lHydroptère broke the outright world record, sustaining a speed of 51.36 knots for 500m in 30 knots of wind. In November 2009, Hydroptère broke the 50 knot barrier for a nautical mile with a speed of 50.17 kts at Hyeres, France.