Building of ships and floating structures (no sports and recreational vessels)
The 200-mile fishing limit has changed fishing patterns and, in recent times, fishing boats are becoming more specialised and standardised. In the United States and Canada more use is made of large factory trawlers, while the huge blue water fleets operated by Japan and the Soviet-bloc countries have contracted. In western Europe, fishing vessel design is focused on compact boats with high catching powe
A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds
Commercial fishing is a high risk industry, and countries are introducing regulations governing the construction and operation of fishing vessels. The International Maritime Organization, convened in 1959 by the United Nations, is responsible for devising measures aimed at the prevention of accidents, including standards for ship design, construction, equipment, operation and manning.
According to the FAO, in 2004 the world’s fishing fleet consisted of 4 million vessels. Of these, 1.3 million were decked vessels with enclosed areas. The rest were open vessels, of which two-thirds were traditional craft propelled by sails and oars. By contrast, nearly all decked vessels were mechanized. Of the decked vessels, 86 percent are found in Asia, 7.8 percent in Europe, 3.8 percent in North and Central America, 1.3 percent inAfrica, 0.6 percent in South America and 0.4 percent in Oceania. Most commercial fishing boats are small, usually less than 30 metres (98 ft) but up to 100 metres (330 ft) for a large purse seiner or factory ship.
Commercial fishing vessels can be classified by architecture, the type of fish they catch, the fishing method used, or geographical origin. The following classification follows the FAO, who classify commercial fishing vessels by the gear they use
A trawler is a fishing vessel designed to use trawl nets in order to catch large volumes of fish.
Outrigger trawlers - use outriggers to tow the trawl. These are commonly used to catch shrimp. One or two otter trawls can be towed from each side. Beam trawlers, employed in the North sea for catching flatfish, are another form of outrigger trawler. Medium sized and high powered vessels, these tow a beam trawl on each side at speeds up to 8 knots.
Beam trawlers - use sturdy outrigger booms for towing a beam trawl, one warp on each side. Double-rig beam trawlers can tow a separate trawl on each side. Beam trawling is used in the flatfish and shrimp fisheries in the North Sea. They are medium sized and high powered vessels, towing gear at speeds up to 8 knots. To avoid the boat capsizing if the trawl snags on the sea floor, winch brakes can be installed, along with safety release systems in the boom stays. The engine power of bottom trawlers is also restricted to 2000 HP (1472 KW) for further safety.
Otter trawlers - deploy one or more parallel trawls kept apart horizontally using otter boards. These trawls can be towed in midwater or along the bottom.
Pair trawlers - are trawlers which operate together towing a single trawl. They keep the trawl open horizontally by keeping their distance when towing. Otter boards are not used. Pair trawlers operate both midwater and bottom trawls.
Side trawlers - have the trawl set over the side with the trawl warps passing through blocks which hang from two gallows, one forward and one aft. Until the late sixties, side trawlers were the most familiar vessel in the North Atlantic deep sea fisheries. They evolved over a longer period than other trawler types, but are now being replaced by stern trawlers. "Drawing". FAO. http://www.fao.org/figis/servlet/IRS?iid=7905.
Stern trawlers - have trawls which are deployed and retrieved from the stern. Larger stern trawlers often have a ramp, though pelagic and small stern trawlers are often designed without a ramp. Stern trawlers are designed to operate in most weather conditions. They can work alone when midwater or bottom trawling, or two can work together as pair trawlers.
Freezer trawlers - The majority of trawlers operating on high sea waters are freezer trawlers. They have facilities for preserving fish by freezing. They are medium to large size trawlers, with the same general arrangement as stern or side trawlers.
Wet fish trawlers - are trawlers where the fish is kept in the hold in a fresh/wet condition. They must operate in areas not far distant from their landing place, and the fishing time of such vessels is limited
Trollers - catch fish by towing astern one of more trolling lines. A trolling line is a fishing line with natural or artificial baited hooks trailed by a vessel near the surface or at a certain depth. Several lines can be towed at the same time using outriggers to keep the lines apart. The lines can be hauled in manually or by small winches. A length of rubber is often included in each line as a shock absorber. The trolling line is towed at a speed depending on the target species, from 2.3 knots up to at least 7 knots. Trollers range from small open boats to large refrigerated vessels 30 meters long. In many tropical artisanal fisheries, trolling is done with sailing canoes with outriggers for stability. With properly designed vessels, trolling is an economical and efficient way of catching tuna, mackerel and other pelagic fish swimming close to the surface. Purpose built trollers are usually equipped with two or four trolling booms raised and lowered by topping lifts, held in position by adjustable stays. Electrically powered or hydraulic reels can be used to haul in the lines.
Jiggers - there are two types of jiggers: specialised
squid jiggers which work mostly in the southern hemisphere and smaller vessels using jigging techniques in the northern hemisphere mainly for catching
cod.
Squid jiggers - have single or double drum jigger winches lined along the rails around the vessel. Strong lamps, up to 5000 W each, are used to attract the squid. These are arranged 50–60 centimetres apart, either as one row in the centre of the vessel, or two rows on each side. As the squid are caught they are transferred by chutes to the processing plant of the vessel. The jigging motion can be produced mechanically by the shape of the drum or electronically by adjustment to the winch motor. Squid jiggers are often used during the day as midwater trawlers and during the night as jiggers.
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Building of ships and floating structures (no sports and recreational vessels)
