Ship

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Fishing Vessels

Modern fishing vessels range from one-person wooden rowboats equipped with hand or casting nets to large, steel-hulled ships that range far from their home ports and track their prey using the latest modern technology. Three main types of fishing ships over 40 m (130 ft) in length currently ply the world’s oceans: trawlers, seiners, and long liners.

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Trawlers

Trawlers catch fish by dragging large nets over the seafloor or through the water, then hauling the nets aboard with motorized winches. The earliest trawlers were sail-powered. Diesel engines power modern trawlers, the largest of which reach 120 m (400 ft) in length. They are usually equipped with facilities for freezing their catch to keep it fresh until they reach shore. Large trawlers can store 8,400 cubic meters (296,600 cubic feet) of frozen fish. Trawlers hunt salmon, shrimp, haddock, and many other types of edible sea-dwelling organisms.

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Seiners

Seiners, like trawlers, catch fish in nets. But on seiners, the mouth of the net is drawn closed before it is hauled aboard. Seine fishing originated in Denmark in the middle of the 19th century and descended from casting nets from shore. Modern seiners normally operate throughout the North Atlantic Ocean, pursuing tuna and other fast-swimming species. They can also be found ranging across the warmer waters of the Pacific in search of tuna or off the coast of South America working the much depleted anchovy stocks (see Fisheries).

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Long Liners

Long liners deploy long fishing lines with hundreds or even thousands of baited fishhooks spaced at intervals. The line is towed for a time and then hauled aboard so fishers can remove fish that have taken the hooks. Long liners tend to be smaller than fishing vessels that use nets—the largest fish for tuna in the Pacific Ocean and measure slightly over 60 m (200 ft) in length. These ships use fishing lines that extend over 100 km (60 mi) behind the ship. Other long liners fish for various species of cod in the North Atlantic.

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Research Vessels

Scientific research ships date from the 1870s, when the United States, Britain, and Germany launched expeditions to conduct oceanic research. The most significant of these was the HMS Challenger expedition led by Sir Charles W. Thomson from 1872 to 1876. Scientists aboard the 60-m (200-ft) sailing vessel spent four years studying the ocean terrain and collecting information on thousands of marine species. The Challenger expedition marked the beginning of the fields of oceanography and deep-sea exploration.

A host of vessels have engaged in scientific research since the Challenger’s day. These vessels conduct research related to oceanography, geology, meteorology, and marine geography. Some scientific research vessels were specially designed and constructed for that purpose, while others have been converted to research vessels after another career. These floating laboratories feature high-tech computers, sonar, and sampling equipment used to study the ocean and its inhabitants. They are usually manned by a professional crew and a separate cadre of scientists. They range in size from relatively small sailing vessels in the tradition of the Challenger to modern craft as large as 90 m (300 ft) in length.

Research vessels are financed and operated by national governments, educational institutions, private research organizations, or partnerships between these organizations. In the 1960s Global Marine Development, a privately owned company, financed the construction and operation of the 120-m (400-ft) Glomar Challenger, named for the famous 19th century British ocean research vessel. Glomar Challenger was the first research vessel built to drill core samples from the deep ocean seabed. Research scientists aboard the ship found evidence that strongly supports the theory of plate tectonics, which holds that Earth’s continents were once joined together and have gradually separated.

The equally well-known research vessel Glomar Explorer was built in 1973, ostensibly to explore the possibility of deep-sea mining for Global Marine Development. Years later, the Central Intelligence Agency revealed that they used the Glomar Explorer to explore and raise a Soviet ballistic submarine that sank in 4,000 m (13,100 ft) of water in the Pacific Ocean. They also revealed that Global Marine’s involvement was meant only to serve as a cover for the top-secret operation. Once the covert operation had been completed, the Glomar Explorer spent two years exploring the feasibility of mining manganese from the ocean bottom.

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