Abstract: The invention relates to a propulsion and lift system for speed boats with a submerged foil. According to the invention, foil (4) includes main lifting surface (11) and hinged trailing edge aileron (12) as well as components (14, 25; 15, 16) to inject gas at high velocity from the lower surface of the main lifting surface and the upper surface of the trailing edge aileron. This provides lift at low speed, in particular lift augmenting at takeoff and defines a nozzle (13) with a two-phase flow which alone provides propulsion at high speed by expansion of a gas-liquid emulsion in said nozzle. Application is to the design of fast hydrofoils.

Abstract: A surface effect vessel of a type comprising a buoyed structure with two side keels (20), a rear seal apparatus (100) and a forward seal apparatus cooperating to delimit a central buoyancy cushion (300). The rear seal contains a horizontal extension enclosure (100). A first piping system (54) connects a pressurized air generator (50) to the enclosure (100), and a second piping system (58) connects the central cushion (300) and the pressurized air generator (50). Fluid communication holes (150) are provided between the enclosure (100) and central cushion (300). The piping system (54, 58) and the fluid communication holes (150) are defined to ensure inflation of enclosure (100) to a pressure higher than the pressure of the central cushion (300).

Abstract: This invention concerns a surface effect vessel whose type comprises a buoyed up structure fitted with two side keels (20), an rear seal apparatus rear and a forward seal apparatus (200) both delimiting a central buoyancy cushion (300). According to the invention the forward seal apparatus (200) consists of an upper horizontal extension shell (210) extending between the two side keels (20) which communicates with the central cushion (300) so as to be supplied by it and two rows of lower multilobe skirts (230, 250) connected below the upper shell (210), which converge towards the center of the central cushion (300) from top to bottom, and whose concavity faces the center of the central cushion (300), the multilobe skirts (230, 250) together delimiting the intermediate chambers (254) which communicate with the upper shell (210) via ports provided in its wall.