Dictionary of Ichthyology  

beam trawl = a trawl with short wings and a head rope attached to a metal or wooden beam 4-12 m long. The beam keeps the net open horizontally while metal frames on each end of the beam keep the net open vertically. The beam has metal runners to support it off the sea floor and the tapering bag net drags over the bottom. These trawls may have tickler chains to disturb the fish so the net does not ride over them. Experimental electrified ticklers have been developed to be less damaging to the sea bed. Beam trawls are used mainly for flatfish (and shrimp).

From Z. L. Tanner (1896), Report upon the Operations of the United States Fish Commission Steamer Albatross for the Year ending June 30, 1894, Washington, D.C. Photograph by Brian W. Coad.

Canadian Museum of Nature