OTTER BOARD Russian patent published in 2003 - IPC

FIELD: fish industry, in particular, trawler equipment. SUBSTANCE: otter board has set of plates arranged in equally spaced relation on carrier carcass, weights and fittings for securing to trawl warp and cables. Carcass is made in the form of tree straps arranged at angles to one another and has isosceles triangle section, with apex of carcass being oriented toward trawl warp. Each of plates is connected to respective strap and is separated from adjacent plates by bushings loosely put onto straps. Loops for connecting to straps of plate remotest from trawl warp are rigidly fixed in plane of said plate by means of frame rigidly secured to plate. Bushings which are put on central strap and on one of side straps are formed as floats, and bushings put on other side strap are formed as weights. Front ends of straps are connected to bracket joined with trawl warp and rear ends of side straps are fixed directly to upper and lower seine ropes of trawl wing. Central strap is connected to them through guy ropes. Plates in plan are made in the form of axially symmetric figure with convex front edge and concave rear edge defined by convex arcs of circle. Radius of arc of circle circumscribing portions of plate front edge exceeds by 1.5 times radius of arc of circle circumscribing portions of plate rear edge. Distance in axis of symmetry of said figure from intersection point of arcs of circle circumscribing portions of plate front edge to intersection point of arcs of circle circumscribing portions of plate rear edge is equal to radius of arc of circle circumscribing portions of plate rear edge. Distance between front and rear edge intersection points is 2.09 the radius of arc of circle circumscribing portions of plate rear edge, and distances from said points to intersection point of arcs of circle circumscribing portions of plate front edge are 1.62 the radius of arc of circle circumscribing portions of plate rear edge. Rigid frame of plate remotest from seine rope is equipped with pivot joints providing pivoting through 180 deg of plate portions relative to axis of symmetry of plate. Otter board of such construction facilitates opening of trawl. EFFECT: reduced dimensions, improved thrust force, increased stability at low towing speeds. 5 cl, 3 dwg