lightship

lightship moored vessel bearing lights and other signal devices to guide ships and warn of hazards to navigation. Lightships are generally stationed at points where a lighthouse cannot be erected; they are given distinctive features (e.g., high bows, special coloring) so as to be readily distinguishable from other vessels, and they have strong hulls, able to withstand consistent pressures. The first lightship in the United States was posted in 1820 (in the Elizabeth River, near Norfolk, Va.). Afterward, for a time, lightships proliferated; but their number has steadily decreased since the end of World War I. They are costly to staff and maintain, and various engineering developments, such as the construction of large radio buoys, have helped to reduce the need for them. Shortly before World War II all U.S. lightships were placed under the control of the U.S. Coast Guard.

lightship n. also light vessel a moored or anchored vessel with a beacon light to warn or guide ships.

lightship, normally a vessel without any means of self-propulsion, though in some countries they were, until recently, fitted with engines and moored over navigational hazards such a shoal or bank where, for whatever reason, it was impracticable to build a lighthouse. The lightship, like a lighthouse, displays a characteristic navigational light at night and a special mark by day, both easily identifiable and marked on charts. They are also equipped with fog signalling equipment and radar beacons, and come, like lighthouses, under the control of the national authorities like Trinity House and the Northern Lighthouse Board. In British and many other waters, they are always painted red and used to carry a crew of three or four, but nowadays they are all automated.