The action of 15 February 1918 was a naval engagement in the Strait of Dover of the English Channel during the First World War. The action took place between a (Imperial German Navy) destroyer flotilla and vessels of the Dover Patrol.
Background Dover Patrol
On 1 January 1918 Vice-Admiral Sir Reginald Bacon, the commander of the Dover Patrol since 13 April 1915, was sacked and replaced by Acting Vice-Admiral Sir Roger Keyes, due to differences between Bacon and a Channel Barrage Committee chaired by Keyes, to study the means of closing the Dover Strait to German U-boats and whether the existing barrage between South Calliper and the Flanders coast was capable of stopping anything. Bacon had proposed that a deep minefield be laid between the Varne Bank and Cap Gris-Nez that had been approved by the Admiralty in July 1917. The committee reported that the existing barrage was no obstacle to ships or U-boats and that its light buoys were useful to submarines navigating the straits.
Dover Barrage
In early October 1914, four British minelayers established a minefield of 1,064 mines from the Goodwin Sands to the Sandettie Bank, despite doubts of their utility,
and before long many broke free of their moorings and drifted with the tides, 17 being detonated by British ships on 23 November. By the end of 1914 the Dover Patrol had sown 3,064 mines across the Dover Strait and off Zeebrugge that sank U-11 on 9 December and U-5 on 18 December 1914.
The original mine barrier being a liability to all, a shorter mine and net barrier was planned with the use of indicator nets in lengths of up to , of thin steel wire, held up with a jackstay and glass floats, intended to entangle submarines, then to be attacked with a lance bomb (an explosive at the end of a pole) while assistance arrived. The nets were laid by drifters, small fishing vessels, in divisions of about six vessels, guarded by armed patrol boats and ships. The new -long indicator net barrier was laid in the Dover Strait in two days. The nets were combined with minefields set at several depths, backed up by patrols of destroyers. Rear-Admiral Horace Hood, the commander of the Dover Patrol had accumulated 140 assorted vessels for the task.
By the beginning of 1918 a deep mine barrage across the Dover Strait from Folkestone to Cape Gris-Nez on the French coast, had been completed. The Germans were ignorant of its existence because U-boats that came across it were destroyed. The minefield worked in combination with a squadron of Royal Navy trawlers and drifters who, upon sighting a submarine, would drive it into the minefield by means of gunfire and flares. Between 18 December 1917 and 9 February 1918, the U-boats (mined 19 December 1917) , (depth charged 19 January 1918) and mined on 8 February 1918, had been sunk by the Dover Patrol or in the Dover Strait.
Prelude
German Plan Over the winter of 1917−1918, the flotillas on the Flanders coast were restricted to defensive operations but for a few sorties, because of a lack of ships. The Germans had not attacked the straits since April 1917 and in the long winter nights, on 23 January 1918 a drifter, Clover Bank was attacked near the Thornton Bank by several German destroyers. The success of the Dover Patrol and the barrage in sinking U-boats led Karl Bartenbach, to request assistance from Ludwig von Schröder the commander of , which was responsible for the defence of the Belgian coast, the northernmost part of the Western Front and air and sea operations against shipping in the English Channel and the southern North Sea. Schröder passed on the request to Admiral Reinhard Scheer, the commander of the High Seas Fleet as the lacked the ships for an offensive operation of sufficient magnitude. Scheer offered the II Destroyer Flotilla ( ) comprising eight destroyers. The flotilla was to sail direct from the German Bight and assemble off the Haaks Lightship (west of Texel) at to deny the British warning of an attack. The destroyers were only to enter Zeebrugge to refuel on the return journey and then return to the German Bight the same night.
Strait of Dover
The commander of the Dover Patrol, Roger Keyes, predicted that the attack on the drifter Clover Bank was the beginning of more German operations but nothing happened for three weeks. Keyes had retained the dispositions of the destroyer protective patrols of his predecessor, keeping a guard force at Dunkirk, protecting the port and the northern flank of the Allied armies in France and another flotilla in The Downs which was resting but kept at short notice to protects ships or reinforce the ships in the straits. Another destroyer division, comprising flotilla leaders and 4-inch gun destroyers, made up the East and West Barrage Patrols, the two groups taking turns.
The barrage patrols operated south of the original net barrage on parallel lines, about long, the western line running north-east from south of the South Goodwin light vessel, the eastern line from No. 9 buoy, part of a line of line of buoys from buoy No. 2 to buoy No. 16 between Folkestone and Cap Gris-Nez. Fifty-eight drifters were organised in nine divisions, usually of seven drifters apiece, each division commanded by a Lieutenant of the Royal Naval Reserve or the Royal Naval Volunteer Reserve guarded the minefield with indicator nets. For about on either side of the deep minefield trawlers, paddle steamers and other small craft illuminated the area with searchlights and flares.
On the night of 14/15 February 1918, the light cruiser and the destroyers , and were resting in The Downs, ready to steam at short notice. The destroyers and were on the West Barrage Patrol and the destroyers , , and comprised the East Barrage Patrol. Six trawlers were north-east of the line of drifters, four trawlers were to the south-west and a third group was off Cap Gris-Nez. The trawlers illuminated the area with flares lit at random intervals. The paddle-minesweepers and patrolled between the south-eastern lightship of the Folkestone Gate and the Varne lightship, with four motor launches watching the passage between the gate and the land.
The drifters and trawlers were guarded by the monitor near the north-east Varne buoy, the destroyer between the Varne lightship and the Colbart Bank and with P.50 between light buoys 30 and 31. The French torpedo boats Torpilleur 344 and Torpilleur 350 patrolled the area between buoy 31 and Cap Gris-Nez. A searchlight at Folkestone swept the area between the port and the Folkestone Gate and other P-boats, when alerted by the drifters of a submarine, were to turn on their searchlights and make a slow sweep from north-west to south-east. The purpose of the Dover Barrage was to prevent German U-boats from using the strait but Keyes doubted that the barrage patrols could prevent a raid by German ships on the drifters and trawlers and gave orders for the drifters to scatter to the nearest shore if attacked, all sightings to be reported by green Very lights.
II Destroyer Flotilla The eight destroyers of the flotilla were due to sail on 7 February but bad weather forced a postponement until 13 February. During the delay the planned route was cancelled because of British minelaying. The flotilla had to sail by the Frisian Islands, with the risk of being spotted from the Netherlands coast and their presence being reported to the British being reported. The fog on 13 February was a welcome screen and the II Destroyer Flotilla passed down the swept channel at Terschelling. When the flotilla arrived at the Haaks Lightship (off the Dutch coast) the attempt has to be delayed because of the persistent fog. To gain surprise the ships had to make a swift passage to the Channel but such poor visibility made this impossible. The flotilla sailed again on 14 February from Den Helder on a westerly course; once out of view from land Heinecke steered south. After night fell the destroyers sailed down the Dutch coast to the Schouven bank but at the Hook of Holland had to turn back with engine-trouble. On reaching the Sandettie Bank Heinecke took the 4th Half-Flotilla to the north of the Colbart bank to attack the ships south of Dungeness and then attack the British vessels from Folkestone to the Varne bank. Kolbe led the 3rd Half-Flotilla to the Cap Gris-Nez end of the Dover barrage and attack northwards. At ( GMT) the 4th Half-Flotilla was about from a paddle minesweeper when the destroyers opened fire.
Action
The night of 14/15 February was very dark and hazy, severely limiting visibility but between and the skipper of Shipmates, a drifter spotted a U-boat about west south-west of No. 12 buoy heading eastwards towards the minefield. The skipper, Lieutenant W. Denson sent up the U-boat signal, red and white very lights and gave chase but the U-boat was lost on the dark. The minesweeper Lingfield and two motor launches saw the signal and investigated then returned to their stations. At the minesweeper Newbury turned east south-east at the end of its beat at the Gate lightship towards the Varne buoy. Two destroyers loomed out of the darkness on a parallel course and fired on Newbury leaving it severely damaged and on fire. The captain, Lieutenant A. D. Thomson, let the ship drift north-east out of the minefield and dropped anchor.
Having not been given time to work up after a recent refit, Thomson could not find the green very lights to give the alert for surface attack. Most of the vessels in the strait had heard the gunfire but many mistook it for artillery-fire in Flanders or from the wrong direction. A signal station in Dover reported the sounds of gunfire from the south-west, soon confirmed by the station at Folkestone but having received a sighting report from Shipmates of a U-boat near no. 12 buoy assumed that this was the cause of the firing. Denson saw gun-flashes but before he could respond Shipmates and its drifter division was swept by searchlights and firing. Denson threw his confidential books overboard and followed standing orders to make for the shore until when he was clear of the attackers. He saw several rockets go up but not having a standing order to repeat signals or able send a wireless message, having jettisoned his code-books, refrained from doing so, looking for his drifter division and returning to his station.
Other vessels heard the second outbreak of firing but when the commander of Lingfield headed to No 12 buoy and saw two ships illuminating with searchlights and firing he took them to be the monitor near the Varne lightship and a destroyer were firing on a U-boat, then reversed course as shells passed overhead. The skipper of the drifter Begonia II, between No. 13 and No. 14 buoys, heard firing from the north-east and north-west but did not speculate as to its cause. The captain of HMS Racecourse on a beat between Varne and the north-east part of Ridge Bank (the Colbart shoal) head firing to the north-east and took it to be an air raid on Dover.
The commander of ML 12, near the south-east gate lightship, heard firing and saw a burning ship to the south-west, then saw two destroyers to the north-east that bombarded ML 12 until it escaped in the dark, the captain convinced that the destroyers were British and had mistaken the ML for a U-boat. As ML 12 made its escape the captain spoke to the commander of the trawler Goeland II who was certain that the destroyers were German. The signal station at Dover contacted the Vice-Admiral Keyes Dover and reported that the firing was continuous but as no green Very lights had been seen it was still thought that a U-boat was being engaged.