User manual SIMRAD PI32 SENSOR MOUNTING INSTRUCTIONS

[. . . ] The total length of the strop, sensor, detector wire and rope determined the distance monitored to the bottom. Shooting - thread the weight on the ring needle (but not around the purse wire) so that the bottom sensor will be deployed first. The weight must hang freely and sink clear of other gear so that it may activate the sensor when bottom contact is made. [. . . ] Complete overview - of the fishing operation is achieved with three sensors marked correspondingly with D1, D2 or D3 and attached to the purse seine as illustrated. Make sure that the attachment locations chosen will not subject the sensor to unnecessary abuse when shooting. Precautions should also be taken when sensors pass through the powerblock. D2 Bottom sensor attachment 1. ) Locate the middle of the footrope and bend the attachment ring for the stay to the "bottom" and two strops attached to karabiners on either side to its "top". The strops should create a bridle about 15 to 20 cm in length that will securely hold the bottom sensor in a stable position. 2. ) Bend the penetration ring for the detection wire about 30 cm below the footrope as illustrated. Attach the bottom sensor and check that its detection wire passes through the centre of the penetration ring. 3. ) Attach the rubber strops so that the bottom sensor is held horizontally when towed. IMPORTANT: Carefully attach the sensor to the inside of the trawl so that it is not subject to damage or torn off during fishing operations. The sensor's detection wire must always be allowed to pass freely through the centre of the penetration ring when it is deployed. Rock hopper, bobbins, etc. Attachment ring for the stay bent securely to the "bottom"of the footrope. If the bottom sensor is attached to the wings, the length of the lashings must be adjusted so that the sensor points toward the mother vessel when towed. Catch sensor attachment Sensor attachment - to a net with an approximate mesh size of 140 mm is illustrated below. The distance between the anchor points for the attachment rings and rubber strops will vary according to mesh size and sensitivity required. Karibiner and screw link Nylon attachment rings, bent to the netting Vessel Steel attachment rings, bent to the netting Note 1 Note 1 Lift Off Touch Down Detection wire 30 cm Detection chain Rock hopper Stay End link Weight Rubber strop Detector wires Karabiner Bottom Note 1: The stay can also be attached to the steel spacer between the bobbins/rock hopper if the footrope is held fairly stable relative to the gear. Contact - bottom sensors can detect bottom contact with a precision of just a few centimeters when correct stay and detection chain lengths are used. Optimal sensor performance requires that these lengths are configured with regard to both each other and the gear in use (the standard delivery includes a 63 cm stay and 39 cm detection chain for use with 14 to 16 inch bobbins or rock hoppers). Configuration - the desired bottom detection distance is relative to the diameter of the rock hoppers, bobbins or other gear in use. This relationship can be determined and precise stay and detection chain length adjustments made as described below. [. . . ] Sensitivity - is determined by the number of mesh squares separating the two rubber strops (a larger number increases sensitivity, a smaller reduces it). Simulate sensor activation by stretching the net's mesh to approximate the load generated by a full catch. Experiment accordingly to determine the correct attachment points and then permanently mark their locations for future reference. [. . . ]