Sub-chaser Detachment 1, Plymouth--Captain L. A. Cotten, commanding; _Hannibal_, repair ship; _Parker_, _Aylwin_, destroyers; 36 to 66 sub-chasers. Submarine Detachment 2, Corfu--Captain C. P. Nelson, commanding; _Hannibal_, repair ship; 36 sub-chasers. Submarine Detachment 3, Queenstown--Captain A. J. Hepburn, commanding; 30 sub-chasers. These were the principal bases, though our chasers also did valuable work from Brest, Gibraltar and other points and at the Azores. Twenty-four sub-chasers assisted in sweeping up the mines of the North Sea Barrage from April to the end of September, 1919, and four were damaged by exploding mines. The sub-chasers played an important part in operations against the German U-boats off the American coast in the summer of 1918. Scores of them were on patrol along the Atlantic, and speeded to the vicinity whenever a submarine was reported. Immediately after the U-151 appeared off the New Jersey Coast, June 2, a special hunting group was formed of 33 sub-chasers, headed by the destroyers _Jouett_, _Henley_ and _Perkins_, and later another group, headed by the _Patterson_, was organized. These hunters kept on the move, pursuing the "subs" for months, from the Virginia Capes to Nova Scotia. Many were kept busy escorting coastwise convoys, and patrolling the coast. One group is reported to have escorted from port, with other naval ships, vessels bearing 400,000 troops. Many chasers were almost constantly at sea. The Hampton Roads Squadron, in command of Lieutenant Herbert L. Stone, averaged 75 per cent of the time on duty. Sub-chasers, under Lieutenant Le Sauvage, in the vicinity of Fire Island, when the _San Diego_ was lost, were on duty 28 days out of 30. Patrolling and listening was dangerous work, for the little boats lying in the shipping lines, with all vessels running without lights, might be run down or mistaken for enemy craft. This was the fate of S. C. 209. Shelled and sunk off Fire Island by the steamship _Felix Taussig_, two of her officers, Lieutenant Henry J. Bowes and Ensign E. H. Randolph, and fourteen enlisted men lost their lives. Keeping open the shipping lines from Mexican and Gulf oil fields was an important duty; it was considered probable that the U-boats would extend their operations to Mexican waters. Consequently we organized a special hunting squadron of 12 sub-chasers, headed by the _U. S. S. Salem_ (Captain S. V. Graham), as a part of the American Patrol Detachment commanded by Rear Admiral Anderson, which patrolled the waters of the Gulf and Caribbean. Twelve sub-chasers served in the Panama Canal Zone, eight being stationed at the Atlantic entrance, and four at the Pacific entrance to the Canal, which it was their mission to protect.