DEVICE FOR MEASURING AND RECORDING THE HORIZONTAL DISTANCE BETWEEN TWO UNDERWATER ELEMENTS OF A TRAWL UNIT ESPECIALLY THE HORIZONTAL WIDTH AT THE MOUTH OF A FISHING NET

摘要

1343806 Measuring length, recording MORSKI INSTYTUT RYBACKI 19 April 1971 [24 Feb 1970] 23476/71 Heading G1J, G1M Apparatus for measuring and recording the distance between two points, e.g the width of the opening of a trawl net when in use, comprises a pair of co-axial drums 6, 7 on which are wound cords 3, 4, the cord 3 being arranged to be unwound from its associated drum 6 by an amount indicative of the distance between the points, such distance being recorded on a recorder actuated by the rotation of the drum 6. As shown, the cord 4 which has a float 5 at its free end rotationally positions the drums 6,7, when one end of the cord 3 is attached to one of the two points and the drums are located at the other of the points, so as to tension the cord 3 by a pre-determined amount, the rotational position of the drum 6, corresponding to the cord length between the two points, being transmitted by gears to a reciprocatable pen 12 mounted on guides 25, 26. A tape driven at constant speed by an electric motor from one roller to another arranged below the pen 12 receives a plot indicative of the distance or change of distance 'with time between the two points. A pressure responsive electric switch (16) Fig. 3, (not shown) protected by a cover (17) on one end of a cylindrical housing 2 in which the recorder is located and to which the drums are connected is arranged to respond to hydrostatic pressure and actuate the drive motor.