The German submarine and destroyer bases at Zeebrugge and Ostend were frequently bombarded by the monitors of the Dover Patrol but, although much damage was done, the lock gates and basins were not hit. The mine and net barrage in the Straits was constantly patrolled by destroyers and drifters and German destroyers made several attempts, by night raids on the patrols, to open a way for their submarines into the Channel. On the night of March 17 a German flotilla attacked the patrol, sank the destroyer "Paragon" and damaged the "Llewellyn." On April 20, they were not so successful, for the raiding flotilla was met by the "Swift" and "Broke" and, in the spirited hand-to-hand fight that ensued the German destroyers "G. 42" and "G. 45" were sunk. Thereafter, except for ineffectual sorties on April 26 and May 2, no raid was made upon the Dover Straits for nearly a year. Further north the Harwich Flotilla was constantly on the alert and on Jan. 23, in a night melee with a flotilla off the Dutch coast, the German leader was forced into Ijmuiden badly crippled, another boat was driven back to Zee brugge and the British destroyer "Simoon" was sunk.
Although to a great extent covered by the Grand Fleet cruisers and escorted by destroyers, the Scandinavian convoy was open to bold attack by the German surface craft and two such attacks were successful. On Oct. 17 two German light cruisers met this convoy of nine vessels, sank the escorting destroyers "Strongbow" and "Mary Rose" and the ships of the convoy without warning and escaped unscathed. Again on Dec. 12 a German flotilla attacked the convoy and sank the destroyer "Pellew" and four armed trawlers, most of the merchant ships escaping. These two mishaps led to a reorganiza tion of this convoy route and to the strengthening of the escorts. The Action of November 17.—Owing to delays in the pro duction of mines, the British policy of intensive mining off the entrances to the German ports was not put in force until October.
This was followed by a great increase in the German minesweep ing service, some of the flotillas having to work as far as 150 miles from Heligoland. In November the Grand Fleet cruisers con stantly raided the Bight and the Cattegat and on Nov. 2 the decoy ship "Kronprinz Wilhelm" was sunk in the latter area.
On Nov. 17, two British light cruiser squadrons, supported by battlecruisers, attacked the German minesweepers and their covering force in the Bight. A long range action followed, the Germans retiring under smoke-screens to the minefields, when two battleships appeared in support and the British force with drew. In this indecisive affair the light cruiser "Konigsberg" was heavily hit and one German outpost vessel was sunk and on the British side the light cruiser "Calypso" was hit and her captain killed. On Dec. 23 three destroyers escorting the Dutch convoy
steamed into a German minefield off the Maas Lightship and were sunk in quick succession. The Grand Fleet suffered a heavy loss when the battleship "Vanguard," on July 9, was lost at Scapa Flow with nearly all hands, owing to an internal explosion.
At the end of the year Admiral Wemyss relieved Admiral Jellicoe as First Sea Lord and Vice-Admiral Keyes took over the command of the Dover Patrol, in succession to Vice-Admiral Sir Reginald Bacon.
A few British submarines operated in the Baltic throughout the year, being employed mainly on reconnais sance work by the Russian Admiral. In October, after Riga was captured by the German Army, an attempt to open up the Gulf of Riga was made by the High Sea Fleet, and a military force was successfully landed on Osel Island. The Straits of Irben were swept but the battleships "Bayern," "Grosser Kurfurst" and "Markgraf" all struck mines. The Russian battleship "Slava" was sunk but after three German battleships had been attacked by British submarines the naval force was withdrawn, leaving Osel Island in military occupation.
After many months of preparation, General Maude commenced his advance up the Tigris in Feb. 1917. The army was supported by a flotilla of eight new river gunboats and a number of armed river steamers. Kut was retaken on Feb. 24 and in the heavy fighting that followed the naval flotilla played a prominent part. The 6-inch and 4-inch guns of the gunboats did much to convert the Turkish retreat into a rout and the British flag was hoisted over Baghdad on March II. (See MESOPOTAMIA, OPERATIONS IN.) The Mediterranean, 1917.—Allied naval strategy was centred in the Adriatic during the year, for the French and Italian battle squadrons had to keep a watchful eye upon the Austrian dreadnoughts. But the enemy submarines and not the battleships became the dominating factor and, using the Austrian bases, they operated all over the Mediterranean. Their target was a vast one consisting of the great volume of trade to the East, swelled by troop and supply ships feeding the armies at Salonika (q.v.), in Egypt, in Syria (q.v.) and in Mesopotamia. The 40-mile Otranto Straits were too deep for mining and were patrolled by 5o British North Sea drifters, supported by British and Italian cruisers and destroyers. Stopping the passage of enemy submarine was a diffi cult task and the patrols were always open to sudden raids. On May 15 Austrian cruisers and destroyers descended upon the patrols and sank 14 drifters before they were chased back to Cattaro by the cruisers "Weymouth" and "Dartmouth." The latter ship was torpedoed during the action but did not sink.