In August and September 1917, six Coast Guard cutters, Ossipee, Seneca, Yamacraw, Algonquin, Manning, and Tampa left the United States to join U.S. naval forces in European waters. They constituted Squadron 2 of Division 6 of the patrol forces of the Atlantic Fleet and were based at Gibraltar. Throughout the war they escorted hundreds of vessels between Gibraltar and the British Isles, as well as escort and patrol duty in the Mediterranean. The other large cutters performed similar duties in home waters, off Bermuda, in the Azores, in the Caribbean, and off the coast of Nova Scotia. They operated either under the orders of the commandants of the various naval districts or under the direct orders of the Chief of Naval Operations.
A large number of Coast Guard officers held important commands during World War I. Twenty-four commanded naval warships in the war zone, five commanded warships attached to the American Patrol detachment in the Caribbean Sea, twenty-three commanded warships attached to naval districts, and five Coast Guard officers commanded large training camps. Six were assigned to aviation duty, two of which commanded important air stations including one in France. Shortly after the Armistice, four Coast Guard officers were assigned to command large naval transports engaged in bringing the troops home from France. Officers not assigned to command served in practically every phase of naval activity, on transports, cruisers, cutters, patrol vessels, in naval districts, as inspectors, and at training camps. Of the 223 commissioned officers of the Coast Guard, seven met their deaths as a result of enemy action.
In 1918, Diamond Shoals Lightship #71 had been warning shipping of the proximity of a German submarine of Cape Hatteras, N.C. The submarine, provoked by the lightship’s warnings, surfaced and, after allowing the 12-man crew to abandon ship, sank it with shellfire. The lightship’s sacrifice was not in vain though, for more than 25 Allied ships had received its timely radio warning.