She also had a cluster of three 100 cp electric lens lanterns mounted in a gallery at each masthead, a twelve-inch steam chime whistle and a hand-operated fog bell weighing 1,000 pounds.

On August 6, 1918, exactly one year and four months after the United States' declaration of war on Germany, the lightship was on station off Cape Hatteras, North Carolina, when her crew sighted the American cargo ship SS Merak sinking nearby.

The Merak had been sailing off Diamond Shoals from New York City to the West Indies when Commander Waldemar Kophamel, of the submarine U-140, attacked her with torpedoes.

LV-71 rescued the survivors; her skipper Master Walter Barnett then sent out a warning to alert friendly ships in the area of a U-boat's presence in the vicinity of the lightship.

The signal was intercepted by U-140, which quickly returned to the scene and sank LV-71 with gunfire after letting her twelve-member crew and the survivors of the Merak row towards shore in a lifeboat.