Patent ID: 8943736
Filing Date: 2015-02-03
Classification: A01K,B63B

Abstract:
1. An otter board that expands a net opening of a trawl net by being towed together with the trawl net by a trawler in a state in which the otter board is connected to the trawler and the trawl net, the otter board comprising: a curved board that is formed into a shape curving in a curving direction corresponding to an expanding direction of the net opening from a front-side end section that is a front side in a towing direction in a towing state towards a rear-side end section that is a rear side in the towing direction in the towing state, and that moves in the expanding direction of the net opening in accompaniment with towing by the trawler, wherein a projecting structure is formed on a surface of the curved board on a curving direction side over a region of a predetermined area on the front side on the surface on the curving direction side, the projecting structure having a projecting surface that projects further outward than the region of the predetermined area and is configured for reducing separation of flow at the front side on the surface and reducing generation of vortexes on the front side on the surface.