User manual SIMRAD PI TRAWL HYDROPHONE INSTALLATION REV B

[. . . ] Installation manual Simrad PI Catch monitoring system Trawl hydrophone installation www. simrad. com MAXIMIZING YOUR PERFORMANCE AT SEA 851-164472 / Rev. B Simrad PI Catch monitoring system Trawl hydrophone installation About this document Rev Rev. B Date 03. 06. 05 Information reorganized Written by RBr Checked by KRa Approved by KRa © 2005 Simrad AS. ISBN 82-8066-055-0 No part of this work covered by the copyright hereon may be reproduced or otherwise copied without prior permission from Simrad AS. The information contained in this document is subject to change without prior notice. Simrad AS shall not be liable for errors contained herein, or for incidental or consequential damages in connection with the furnishing, performance, or use of this document. [. . . ] · Hydrophones have a vertical coverage of approximately 30 degrees. The normal tilt angle is 20 degrees; if the system is to be used in deep water the hydrophones should be tilted preferably 30 degrees and in shallow water preferably 10 851--164472 / Rev. B 11 Simrad PI Catch monitoring system / Trawl hydrophone degrees. To maximise coverage using two hydrophones when trawling in both deep and shallow water tilt one preferably 15 degrees and the other preferably 30 degrees. The hydrophone closes to the propeller should be tilted the most and care should be taken with regard to underwater acoustical noise. · Hydrophone cables pass through a vessel's hull below its water-line. It is therefore strongly recommended that a length of conduit be fitted (using approve fastening procedures) to the interior of hull around the opening made for the hydrophone's cable. This conduit should extend vertically (inside the vessel) over the water-line so that hydrophone cables can be safely passed through the hull without the danger of flooding in the event of gland failure. Hydrophones with steel through-hull fittings installed in this manner can be replaced without the necessity of dry docking. · The cable between the hydrophone and the cabinet must be properly shielded from other potential sources of electrical interference. A good practice is to run the hydrophone cable in a steel conduit to the wheel house. Figure 1 Recommended hydrophone locations The illustration shows the recommended (A) and the alternative (B) locations for single hydrophone locations. For a dual installation, use position (A), and place the port hydrophone further aft than the starboard. (L) is the total length of the hull measured at the waterline. 12 851--164472 / Rev. B Installation manual Coverage area, orientation and tilt Once the fore-and-aft placement of the hydrophone is decided, it is equally important to carefully consider its horizontal and vertical orientation. Hydrophone orientation can have a large influence on system performance. Hydrophones must be configured so that they overlap one an other in the horizontal plane. If fishing operations are to be conducted in both deep and shallow water the hydrophones can be tilted differently. Horizontal coverage area The hydrophone's beam sensitivity is concentrated within a 50 degrees horizontal and -30 degrees vertical sector. By off-setting hyprophones by 20 degrees each from the vessel's centre line an overlapping coverage area of 20 degrees is provided with a total coverage area of 90 degrees. Horizontal coverage area (A) = Starboard hydrophone (B) = Port hydrophone This "rule-of-thumb" is for normal trawling operations. For pair-trawling or when fishing with Danish seines, the horizontal position of the hydrophones should be configured with regard to the operation in question. 851--164472 / Rev. B 13 Simrad PI Catch monitoring system / Trawl hydrophone Vertical coverage area I Dual hydrophone installation with hydrophones equally distant from the bow, but tilted differently. Typical tilt configuration for operation in both deep and shallow water when the hydrophones have the same distance from bow. (A) = Using shoes (top view) (B) = Using blisters (top view) (C) = Port hydrophone tilted 10 to 20 degrees (D) = Starboard hydrophone tilted 20 to 35 degrees (K) = Keel The hydrophone on the starboard side of the hull should have the greater tilt of the two, approximately 20 to 35 degrees. The hydrophone on the port side of the hull should be tilted approximately 10 to 20 degrees 14 851--164472 / Rev. B Installation manual Vertical coverage area II Dual hydrophone installation with hydrophones different distances from the bow, and tilted differently. Typical tilt configuration for operation in both deep and shallow water when hydrophones have different distances from bow. (A) = Port hydrophone tilted 20 to 35 degrees (B) = Starboard hydrophone tilted 10 to 20 degrees The hydrophone closest to the main propeller should be on the port side of the hull and have the greater tilt of the two, approximately 20 to 35 degrees. The hydrophone on the starboard side of the hull should be tilted approximately 10 to 20 degrees Note: The "tilt angle" is measures from the vessel's water-line toward the bottom when in operation. A vessel's hull and keel are normally not parallel with the water-line and/or the bow may lift when trawling. [. . . ] A possible solution in such cases is to run the hydrophone cables in a steel conduit aft along the hull until a suitable cable gland location is available. The respective cable gland can then be installed as described in the following instructions. Note: Simrad takes no responsibility for the correct installation of cable glands, associated hull modifications and/or structural support of hydrophone cable penetration. These activities are subject to individual approval by the respective classification society for the vessel in question. Order numbers Steel hull cable gland kit: 599-202216 Wood/GRP hull cable gland kit: 119-038200 Small vessel cable gland kit: 599-202182 851--164472 / Rev. B 27 Simrad PI Catch monitoring system / Trawl hydrophone Cable gland installation for steel hulls The cable gland kit for steel vessels is included with standard deliveries. The drawing shows a single hydrophone, but normally a typical installation includes two hydrophones with respective cables spliced in a junction box and run to the wheelhouse in a conduit. [. . . ]