The Germans attempted to repeat their successful attack of 26-27 October 1916 on the Dover Straits anti-submarine net barrage and shipping on 23 November 1916, but it and a raid of 25-26 February on shipping between England and the Hoof of Holland did little damage.
A new attack on the Dover Straits was planned for 17-18 March 1917. Seven destroyers (802-960 tons, three 10.5 cm (4.1 inch) guns, six 50 cm (19.7 inch) torpedo tubes, 33.5-34 knots) of the 6th Flotilla would operate in the western half of the Dover Straits, five (852-990 tons, three 105 cm guns, six 50 cm torpedo tubes, 32-33.5 knots) of the 1st Zeebrugge Half Flotilla in the eastern half and four (568 tons, two 88 mm (3.45inch) guns, four 50cm torpedo tubes, 29 knots) of the 2nd Zeebrugge Half Flotilla in the Downs off the east coast of Kent. Korvettenkapitän Tillesen of the 6th Flotilla would lead the attack. Tillesen planned the operation carefully in order to give each group of destroyers separate lines of approach and areas of operation.
The British had the K class HMS Paragon (1072 tons, three 4 inch guns, two 21 inch torpedo tubes with 4 torpedoes, 29 knots) and three L class (965-1010 tons, three 4 inch guns, one .303 inch MG, four 21 inch torpedo tubes, 29 knots) destroyers protecting the net barrage, a light cruiser, a flotilla leader, four destroyers and two monitors off Deal and a flotilla leader and five destroyers at Dover.
At 2250 HMS Paragon encountered three or four destroyers. She exchanged gunfire with them and fired a torpedo that hit a German ship without exploding. Paragon then blew up and sank with the loss of all but 10 men.
HMS Laforey, assuming that Paragon had struck a mine, stopped at about 2300 and switched on her searchlight in order to see and pick up survivors. About 2315 she was narrowly missed by a torpedo that damaged HMS Llewellyn. Laforey’s captain assumed that it had come from a U-boat so set off in search of a submarine. Other British ships therefore remained in port.
The German destroyers attacking the Downs came across the SS Greypoint, which was anchored in an exposed position because her engines had broken down. They torpedoed and sank her, damaged a drifter and bombarded Broadstairs and Ramsgate without causing much damage, although some civilians had narrow escapes. They then withdrew, outpacing Torpedo Boat 4, the only British warship to spot them.
The British casualties are listed on Naval-History.net.
 J. S. Corbett, H. Newbolt, Naval Operations, 5 vols. vol. iv. pp. 361-62; R. Gray, Conway’s All the World’s Fighting Ships, 1906-1921, pp. 168-69; P. G. Halpern, A Naval History of World War I, p. 348.
 Corbett, Newbolt, Naval. vol. iv. pp. 361-62; Gray, Conway’s 1906-1921, pp. 75-76.
 Naval Staff Monograph (Historical) 1922 vol. vi, The Dover Patrol i. p. 92.
 Ibid., pp. 92-93.
 Ibid., p. 94.
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