A fishing trawler, also known as a dragger, is a commercial fishing vessel designed to operate fishing trawls. Trawling is a method of fishing that involves actively dragging or pulling a trawl through the water behind one or more trawlers. Trawls are fishing nets that are pulled along the bottom of the sea or in midwater at a specified depth. A trawler may also operate two or more trawl nets simultaneously (double-rig and multi-rig).
There are many variants of trawling gear. They vary according to local traditions, bottom conditions, and how large and powerful the trawling boats are. A trawling boat can be a small open boat with only 30 horsepower or a large factory ship with 10,000 horsepower. Trawl variants include beam trawls, large-opening midwater trawls, and large bottom trawls, such as "rock hoppers" that are rigged with heavy rubber wheels that let the net crawl over rocky bottom.
(詳細はDogger, an early type of sailing trawler commonly operated in the North Sea. The Dogger takes its name from the Dutch word ''dogger'', meaning a fishing vessel which tows a trawl.〔Oxford Companion to Ships and the Sea, p. 256〕 Doggers were slow but sturdy, capable of fishing in the rough conditions of the North Sea.〔Fagan 2008〕
The modern fishing trawler was developed in the 19th century, at the English fishing port of Brixham. By the early 19th century, the fishermen at Brixham needed to expand their fishing area further than ever before due to the ongoing depletion of stocks that was occurring in the overfished waters of South Devon. The Brixham trawler that evolved there was of a sleek build and had a tall gaff rig, which gave the vessel sufficient speed to make long distance trips out to the fishing grounds in the ocean. They were also sufficiently robust to be able to tow large trawls in deep water. The great trawling fleet that built up at Brixham, earned the village the title of 'Mother of Deep-Sea Fisheries'.
This revolutionary design made large scale trawling in the ocean possible for the first time, resulting in a massive migration of fishermen from the ports in the South of England, to villages further north, such as Scarborough, Hull, Grimsby, Harwich and Yarmouth, that were points of access to the large fishing grounds in the Atlantic Ocean. The small village of Grimsby grew to become the 'largest fishing port in the world'〔(Days out: “Gone fishing in Grimsby” ) ''The Independent'', 8 September 2002〕 by the mid 19th century. With the tremendous expansion in the fishing industry, the Grimsby Dock Company was opened in 1854 as the first modern fishing port.〔(【引用サイトリンク】title=A brief history of Grimsby )〕 The facilities incorporated many innovations of the time – the dock gates and cranes were operated by hydraulic power, and the Grimsby Dock Tower was built to provide a head of water with sufficient pressure by William Armstrong.〔(【引用サイトリンク】title=Great Grimsby )〕
The elegant Brixham trawler spread across the world, influencing fishing fleets everywhere. By the end of the 19th century, there were over 3,000 fishing trawlers in commission in Britain, with almost 1,000 at Grimsby. These trawlers were sold to fishermen around Europe, including from the Netherlands and Scandinavia. Twelve trawlers went on to form the nucleus of the German fishing fleet.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』