During May, 1917, it was also announced that American warships had arrived safely in British waters and had begun patrol operations in the North Sea. At about the same time Japanese warships made their appearance at Marseilles to assist in the war against submarines operating off the French coast.
On May 15, 1917, Austrian light cruisers operating in the Adriatic Sea, sunk fourteen British mine sweepers, torpedoed the British light cruiser Dartmouth, and sunk an Italian destroyer.
An engagement occurred between a French and a German torpedo-boat flotilla on May 20, 1917, during which one of the French boats was damaged. A few days later British warships bombarded Ostend and Zeebrugge. Six German destroyers engaged in a running fight with a British squadron, as a result of which one German destroyer was sunk and another damaged. On May 29, 1917, a Russian squadron, operating along the Anatolian (south) coast of the Black Sea bombarded four Turkish-Armenian ports and destroyed 147 sailing vessels carrying supplies.
Thirteen Bulgarian ships successfully bombarded the Greek port of Kavala, then occupied by Allied forces.
Fort Saliff on the Red Sea was captured by British warships. Fort Saliff is a Turkish fortress on the Arabian coast of the Red Sea.
Nothing of importance happened during June, 1917.
Early in July, 1917, a German submarine bombarded Ponta Delgada in the Azores, but was beaten off by ships lying in the harbor, including an American transport.
On July 17, 1917, it was announced that British destroyers had attacked a flotilla of German merchant ships on their way from the Dutch port of Rotterdam to Germany, sinking four and capturing four others.
Mines, submarines, and explosions also made inroads on the naval establishments of the various belligerents. During February, 1917, the Russian cruiser Rurik was damaged by a mine in the Gulf of Finland. On February 28, 1917, a French torpedo destroyer was sunk by a submarine in the Mediterranean.
On March 19, 1917, the French warship Danton was torpedoed in the Mediterranean, 296 of her crew having perished.