SHIP WITH PARTIALLY SUBMERGED SCREW PROPULSOR Russian patent published in 1998 - IPC

FIELD: shipbuilding; operation of ships in clean waters and in polluted waters. SUBSTANCE: propulsor includes two screws located symmetrically relative to CL after intersection f stern break and bottom of ship formed in area of waterline (below its level) as angular shoulder with sharp edge. Projections of lower generatrix of screw hub and line of intersection of stern break with ship's bottom on plane of midship section are aligned. Axis of rotation of screw forms angle with CL which is equal to pitch of blade winding at half its height reduced by 5 to 10 deg. Heights of blades in each cross section of screws are limited by magnitude equal to 0.75 diameter of hub. Outer edges of blades are pointed. Fairing fitted before starting shears of screws is symmetrical relative to CL. Telescopic devices, for example transom boards with interceptors are mounted on ship's hull before screws. Extremities of screws are brought together till direct connection with flanges of output shafts of single transfer reducer placed in fairing. EFFECT: improved propulsive characteristics. 3 cl, 2 dwg