FIRST U.S. LIGHTSHIP ENTERS SERVICE     At least six lightships were in use off England's coasts before the United States even ventured into the concept of lightships. The first U.S. contract was awarded in 1819 to John Pool of Hampton, Va., for a vessel " ... of 70 tons burthen, copper-fastened a cabin with four berths, at least spars, a capstan, belfry, yawl and davits." Delivered in the summer of 1820, this first "light boat" was initially stationed off Willoughby Spit, Va., as an aid to Chesapeake Bay commerce. Storms and heavy seas, however, scourged this exposed position, and the vessel had to be shifted to a safer anchorage off Craney Island near Norfolk, Virginia. The lightship proved as successful on this side of the Atlantic as it had on the other. During the period 1820 - 1983, 116 lightship stations were established by the United States at one time or another. This figure includes those stations which were renamed and moved to a different position to better serve the same purpose, and those taken over later by Canada. The number of stations existing at any one time peaked in 1909 when 56 lightships were maintained. By 1927, 68 stations had been discontinued replaced by lighthouses or buoys, taken over by Canada, or considered unnecessary. In 1939, when the Coast Guard assumed responsibility for aids to navigation, the number of stations had been reduced to 30, and although three additional stations were established during the 1954-1965 period, the total number of lightship stations continued to decline steadily until 1983 when replacement of the Nantucket Shoals Lightship with a large navigational buoy marked the end of America's lightship era.