DEVICE FOR REDUCING SHIP'S MOTIONS IN SWELL Russian patent published in 2003 - IPC

FIELD: shipbuilding; devices for reducing ship's motions in swell. SUBSTANCE: proposed device is provided with side controllable rudders located on either side in vicinity of midship section; they may be retracted inside hull. Mounted in parallel relative to rudder blade is at least one additional blade connected by means of parallel struts whose ends are articulated with each blade. Ends of struts connected with one of blades are provided with mechanism for turning them through 90 deg. Upper blades are secured at extensible power cylinders for performing reciprocating motion along their longitudinal axles which run through recesses made in ship's sides bear bilge. Length of parallel struts between axes of hinges is equal to double length of chord of upper blade. Blade area is determined from the following expression : S = (0,03-0,035)V^2/3, where V is ship's displacement. Sizes of recess make it possible to arrange both blades in it. Its length does not exceed total length of blades and width does exceed their total width. EFFECT: enhanced efficiency at running speed of ship of 12-14 knots at rather small outreach of rudders. 3 dwg