On 27 May, 1918, as the submarine chasers were heading for their assigned ports, the captain of the Otranto Mobile Barrage Force issued a notice about plans to use searchlights on the shore to help the vessels on the barrage line maintain their positions. A schedule was set up to light different searchlights on shore during several different prearranged time periods. The chasers and other vessels on the barrage line could then refer to the schedule and maintain their positions relative to the searchlights. Soon they would be on patrol, hunting U-boats.
Document: Mobile Barrage Confidential Temporary Memorandum: Navigational Lights, 27.5.1918. G.S. Dole Collection.
Photo overlay: chasers at sea. From Hunters of the Steel Sharks: The Submarine Chasers of WWI. G.S. Dole Collection.