Abstract: A propulsion system of displacement or semi-displacement ships, includes one or more propellers of semi-submerged type, arranged with a partial immersion of the sole bottom blades and with the top blades emerged, regardless of the state of motion and the trim of the craft. The propulsion system allows, employed power being equal, a higher propulsion efficiency and allows to keep the driveline of the propellers entirely above water level, wherein the semi-submerged propellers are arranged at the transom, the ratio of diameter (D) or sum of diameters (Np×D) of the semi-submerged propellers to craft width (L) at the water line (3) is greater than 0.50.
Abstract: A marine drive system (1) with a partially submerged propeller located at the transom of a boat comprising, for each propeller (2), a forward-opened shroud (20), positioned above the propeller (2), such as to define, between it and the water level, a channel (23) extending longitudinally and having, at the propeller (2), a cross-section whose area decreases from the transom (30).
Abstract: A propulsion system of displacement or semi-displacement ships, includes one or more propellers of semi-submerged type, arranged with a partial immersion of the sole bottom blades and with the top blades emerged, regardless of the state of motion and the trim of the craft. The propulsion system allows, employed power being equal, a higher propulsion efficiency and allows to keep the driveline of the propellers entirely above water level, wherein the semi-submerged propellers are arranged at the transom, the ratio of diameter (D) or sum of diameters (Np×D) of the semi-submerged propellers to craft width (L) at the water line (3) is greater than 0.50.
Abstract: A marine drive system (1) with a partially submerged propeller located at the transom of a boat comprising, for each propeller (2), a forward-opened shroud (20), positioned above the propeller (2), such as to define, between it and the water level, a channel (23) extending longitudinally and having, at the propeller (2), a cross-section whose area decreases from the transom (30).