Abstract: The invention relates to a boat comprising a platform (52), at least one main, completely submerged, streamlined float (51), integral with the platform (52) by one or more supporting pylons (16) which take up the full weight of the platform (52) to keep it out of the water, arms (14) radiating out from the platform (52), which are substantially horizontal and which support submersible struts (5) extending into the water, fitted with submerged orientable ailerons (1, 2) with hydrodynamic lift effect, said arms (14) being located above the water, mobile streamlined fairings (6), freely rotating under the effect of the local current and individually enveloping each supporting pylon (16) and each submersible strut (5), at least three auxiliary closed-hull floats (53), watertight and streamlined, spaced around the platform (52) to ensure balanced trim when immobile or at low speed, integral with the radiating arms (14) or with the platform (52).