A method for adjusting the angle of attack of an Antarctic krill trawl horizontal expansion device

Abstract

A method for adjusting the work attack angle of a euphausia superba dragnet horizontal expanding device adopts a V-shaped cambered surface net plate. The V-shaped cambered surface net plate is characterized in that the aspect ratio of the V-shaped cambered surface net plate is larger than or equal to 2.7, a steel warp pull plate is welded to a middle steel warp plate between a rear diversion plate and a rear main panel, five longitudinally-arrayed steel warp pull holes are formed in the steel warp pull plate, one is selected from the five steel warp pull holes to be connected with steel warp and used for adjusting the tension angle of the net plate, adjusting the inside and outside inclination state of the device in water and changing the working water depth of the horizontal expanding device, the steel warp pull plate is connected with the steel warp through a steel warp detaching buckle, six cross rope pull holes are formed in the rear side of an upper cross rope plate of the V-shaped cambered surface net plate, six cross rope pull holes are correspondingly formed in the rear side of a lower cross rope plate, and an upper cross rope and a lower cross rope of a net sleeve manrope of a dragnet of a trawler are connected with the cross rope pull holes, with corresponding sequencing numbers, of the upper cross rope plate and the lower cross rope plate through cross rope detaching buckles respectively, so the work attach angle is adjusted. The method is suitable for a low-dragging-speed euphausia superba dragnet.

Description

technical field [0001] The invention relates to a horizontal expansion device for an Antarctic krill trawl and a method for adjusting its operating angle of attack. Background technique [0002] At present, most of the horizontal expansion devices of the trawl nets equipped by fishing boats fishing Antarctic krill in my country are vertical curved mesh panels with relatively simple structure, and can obtain large horizontal expansion at a relatively high towing speed (2-3m / s), which satisfies such requirements. The configuration of the middle-level trawl needs to be used, but it is difficult to obtain the ideal horizontal expansion effect when the hauling speed is low. Professional krill trawls are shallow surface trawls with large net openings and low hauling speed (about 1m / s), so they need to be equipped with expansion devices with better expansion effects. The expansion effect of the expansion device is affected by many factors. In actual use, the expansion force can be ...

AI Technical Summary

Problems solved by technology

[0002] At present, most of the horizontal expansion devices of the trawl nets equipped by fishing boats fishing Antarctic krill in my country are vertical curved mesh panels with relatively simple structure, which can achieve a large horizontal expansion at a relatively high towing speed (2-3m / s). The configuration of the mid-level trawl is required, but it is difficult to obtain the ideal horizontal expansion effect when the hauling speed is low

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