"The first otter trawl was built in Scotland in 1892. Instead of a beam, which would work only where the ocean floor was flat, the bottom opening of the otter trawl was maintained by a chain, which was made more mobile by metal bobbins, rollers, beneath it. The upper side of the opening was held up by floats. The net was kept wide open horizontally by "doors," heavy armored planks on either side of the net. The otter trawl is the prototype of all modern bottom draggers. By 1895, it had become the standard fishing rig of the British North Sea fleet, and very quickly the other European nations that competed in the North Sea fishery converted to otter trawls."
—Mark Kurlansky, Cod: A Biography of the Fish That Changed the World (New York: Penguin, 1997), 131