Hydroptère is an experimental sailing hydrofoiltrimaran designed by French yachtsman Alain Thébault. Its multihullhydrofoil 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 Éric Tabarly since the 1990s. On 5 October 2008 she reached a record speed of 52.86 knots (97.90 km/h; 60.83 mph), however this was over a shorter distance than the 500m necessary to qualify for an official world record. On 21 December 2008, the Hydroptère briefly reached 56.3 knots (104.3 km/h; 64.8 mph) near Fos-sur-Mer, but capsized and turtled shortly thereafter.
On 4 September 2009, the Hydroptère broke the outright world record, sustaining a speed of 52.86 knots (97.90 km/h; 60.83 mph) for 500 m (1,600 ft) in 30 knots (56 km/h; 35 mph) of wind. In November 2009, she broke the 50-knot (93 km/h; 58 mph) barrier for a nautical mile with a speed of 50.17 knots (92.91 km/h; 57.73 mph) in Hyères, France.