Patent GB-995138-A (GB)
Title: Improvements in and relating to trawling and trawlers
IPC: A01K73/06
Filed: 1961-11-03
Abstract: 995,138. Fishing trawls. SIR C. D. BURNEY. Dec. 19, 1962 [Nov. 3, 1961], No. 39541/61. Heading A1A. [Also in Divisions B7 and B8] A trawling system comprises a plurality of trawl nets towed by one trawler, each net having an upper warp 3, 4, 6, 7 extending from each upper mouth corner and a ground line extending from each lower mouth corner, the ground line and upper warp from one side of the mouth being connected to a further warp 64, 65 connected to a towing cable 51, adjacent upper warps 3, 4 being connected directly or by a transverse warp 47 and the two outer upper warps 6, 7 being connected to buoyant otters 13. The ground lines are provided with weights 21, 169. The weights 21 comprise short metal units of square or rectangular section having bores through which the ground line passes. A hemispherical end of one weight engages in a like recess in an end of an adjacent weight. The weights may be small enough to allow the ground line to be wound round the winch of the trawler or the weights may be threaded on to a chain having a hook at one end and a pair of rings at the other end. The chain is inserted into the ground line between ends thereof having a hook-like plate and a pair of rings, Fig. 12 (not shown). At streaming of the trawl one of the rings on an end of the ground line is engaged on a strong point on the trawler and the chain is then inserted between the other ring and the hook on the other end of the ground line. The otters are connected to the trawl by a warp having a hook engaging a swivel in the net warps. This hook can be disengaged at hauling in after engaging a ring in the otter warp with a strong point on the trawler. A swivel for use in the warps comprises a rod, Fig. 4 (not shown), with two or more chromium plated flanges disposed in a casing having interal chromium plated ribs between which the flanges engage. The casing is formed in two halves secured together by bolts and has an external apertured plate to receive the warps; the rod has a ring. Grease is forced into an axial box in the rod leading to radial bores and axial bores in the flanges. Another swivel, Fig. 11, comprises a swivel pin 53 extending into a cylindrical casing closed at one end by an integral apertured plate 31. A circular nut 54 is secured to the inner end of the swivel pin and a ball bearing 56 is mounted on the swivel pin. The other end of the casing is closed by a screw-threaded closure member 52. A ball race may be mounted on the swivel pin outside the casing. The hook on the end of the warp from the otter engages a loop on a sleeve carried by the ball race. Part of the ground line may be protected by loose steel ferrules between steel ferrules which are clamped by hydraulic pressure on to the line. This part of the ground line may be made in detachable lengths and is made weaker than the remaining part. Guide means adjacent the uppermost point of the rear shoot of the trawler for guiding the net cable along a point close to the side of the deck opposite to that from which it is being hauled comprises two bollards having hinges so that they can be moved from transverse recesses in the deck to upright positions. Each bollard comprises a toothed segment engaging a worm on a shaft rotated by gearing. Specifications 633,028 and 798,926 are referred to.