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Deck TypeNormally decked vesselsOverviewOtter trawlers tow one or several parallel trawls that are kept horizontally open with the aid of otter boards. Such trawls can be towed on the bottom and in midwater. The vessel might be of any size from sail-driven canoes to large supertrawlers. The biggest trawlers are included in this vessel class. Generally otter trawlers are equipped with two stern gallows with towing blocks through which the towing warps are running. Otter trawlers have normally two towing warps that are regulated from two winches. Medium sized and large trawlers are often fitted with a stern ramp, on which the trawl is hauled onto the deck. Modern trawlers might be equipped with three towing warps and three winches, towing two parallel trawls (twin trawling). Otter trawlers also include outrigger trawlers towing one or two trawls from outriggers on both sides. Trawls towed from each outrigger are spread horizontally with two otter boards on each side.Vessel ClassLengthnormally > 10  (Actualmetres) Tonnagenormally > 5  (Gross in register tons) Deck ArrangementThe superstructure can be placed in the forward part, amidships or aft. Modern trawlers have, however, normally the superstructure in the forward part. Gallows are placed on the stern quarters or there is a stern gantry for the operation of the otter boards. Net drums and gilson winches are installed to assist in the handling of gear and catch. Larger and medium sized trawlers are often fitted with a stern ramp on which the trawl is hauled onto the deck.Catch Handling and Processing EquipmentFish can be kept fresh in boxes or in containers frequently chilled with ice, frozen in blocks or single-frozen (shrimp), processed to filets, bulk-kept in fish hold or tanks chilled with ice and refrigerated sea water (RSW).EquipmentDeck EquipmentThere will be various arrangements of the deck equipment depending on the type of trawler concerned. All trawlers will carry at least two trawl winches for handling and storage of the towing warps. Gilson winches, net drums and other auxiliary winches are commonly installed to handle the gear and the catch. Pelagic trawlers may be equipped with fish pumps for emptying the codend.Fish Detection EquipmentAccording to its size, the otter trawlers may be fitted with fish detection equipment such as echosounder and sonar. Various gear control and monitoring equipment are widely used; like net sounder that give information about fish concentrations over, under and in the trawl opening, plus clearance from the bottom and opening of the trawl, catch sensors that gives information about the filling rate of the codend; symmetry sensors that provide information about the trawls optimal geometry; tension sensors, that gives information about the tension in warps or sweeps. Important equipment for efficient capture with otter trawls also include navigational instruments, which increasingly is based on the Global Positioning System (GPS).Fishing Gear Bottom trawls, .
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