North Sea Mine Barrage

The objective was to inhibit the movement of U-boats from bases in Germany to the Atlantic shipping lanes bringing supplies to the British Isles.Rear Admiral Lewis Clinton-Baker, commanding the Royal Navy minelaying force at the time, described the barrage as the "biggest mine planting stunt in the world's history.[2] The idea of a mine barrage across the North Sea was first proposed in the summer of 1916 by Admiral Reginald Bacon and was agreed at the Allied Naval Conference on 5 September 1917.The Royal Navy—and in particular Admiral Beatty as Commander in Chief of the Grand Fleet—was skeptical about the value of the operation and did not feel it justified the large logistical and manufacturing commitment required.Assistant Secretary of the Navy Franklin D. Roosevelt appealed directly to President Woodrow Wilson[4] to overcome opposition to the project from Vice Admiral William Sims, who commanded all United States naval forces in Europe.[6] Eight civilian steamships were converted to minelayers; and another 24 mine-carrying freighters, sailing at a rate of two or three per week, were required to transport manufactured mine components to assembly depots in Scotland.Where possible, longitude was determined from a calibrated taut-wire anchored near a landmark and unreeled from a 140-mile (230 km) spool of piano wire aboard one of the cruisers acting as the minelaying formation guide.A covering force of battleships with Royal Navy cruiser squadrons maneuvered nearby to defend the minelaying formation, but no German surface warships attempted engagement.Premature detonations increased to 14 percent for the fourth minelaying excursion because some mines had been assembled with the more sensitive antenna fuze relay settings made by the Bureau of Ordnance.San Francisco identified relay armature sensitivity as a major cause of premature detonations during a comparative field test minelaying excursion on 12 August.Subsequent investigations revealed copper sulfate deposits caused by antenna corrosion created a weak battery, increasing the probability of relay activation by shock wave accelerations when nearby mines detonated.[1] United States participation in the minesweeping effort was overseen by Rear Admiral Strauss aboard the repair ship Black Hawk, from which he had commanded the minelaying operation.Twenty Admiralty trawlers with American crews, 16 more Lapwing class minesweepers, and another repair ship Panther were assigned to his command.Some of this countermining was attributed to acceleration of the antenna fuze relay armature or seawater leaking into damaged mines rather than sympathetic detonation of explosives.Three more men of the minesweeping force were killed in individual accidents involving sweeping gear before Strauss declared the barrage cleared on 30 September 1919.[21] The minesweepers found only about 25 to 30 percent of the mines laid a year earlier;[22] but it was assumed the others had either broken free, sunk to the bottom, or been destroyed by premature explosions.
A Mk 6 mine atop its anchor. Two horn fuzes are visible, but the antenna fuze cannot be seen in this image.
Only the two smallest of the eight steamships converted to lay the barrage remained in commission for conventional minelaying operations. USS Shawmut , shown laying the North Sea mine barrage, sank 23 years later during the attack on Pearl Harbor after being renamed Oglala .
USS Eider (Minesweeper No. 17) (left) in port with submarine chasers alongside during the clearance of the North Sea Mine Barrage in 1919. The leftmost submarine chaser is either SC-254, SC-256 or SC-259 and the others are (left to right) SC-45, SC-356, SC-47, and SC-40.
Northern BarrageWorld War INorth SeaUnited KingdomUnited StatesGermanyU-Boat Campaign1st Heligoland Bight22 September 19141st YarmouthScarborough/Hartlepool/WhitbyCuxhaven1st Dogger BankNoordhinder BankLowca/Parton2nd Dogger Bank29 February 19162nd YarmouthJutland19 August 19161st Dover Strait16 March 19172nd Dover Strait4 May 1917Lerwick2nd Heligoland Bight11–12 December 1917Action of 15 February 1918Zeebrugge1st Ostend2nd OstendTondern24 October 1918minefieldOrkney IslandsUnited States NavyRoyal NavyU-boatsAtlanticBritish IslesRear AdmiralLewis Clinton-BakerWorld War IIReginald BaconAdmiral BeattyGrand FleetAssistant Secretary of the NavyFranklin D. RooseveltPresidentWoodrow WilsonVice AdmiralWilliam Simswire ropeexplosivesDetroitautomobileNorth AtlanticEnglish ChannelxyleneUnited States Armyhydrostaticspringdry cellelectrolytecopperbatteryarmaturemillivoltsBureau of OrdnanceUtsiraBergenJoseph StraussUSS Black HawkReginald R. BelknapInverness, Scotlandattack on Pearl HarborUSS San FranciscoUSS BaltimoreUSS AroostookUSS ShawmutUSS CanandaiguaSouthern PacificUSS RoanokeUSS CanonicusUSS HousatonicUSS SaranacUSS Quinnebauglongitudepiano wireLatitudedestroyerscovering forcebattleshipscruiserhydrophonesdetonationscopper sulfatecorrosionshock waveaccelerationsImperial German NavySM UB-12SM U-92SM UB-127SM U-156SM U-102SM UB-104SM UB-113SM UB-123AdmiraltyPatapscoPatuxentserratedLapwing class minesweeperssubmarine chaserstrawlersPantherTurkeyKingfisherFalconPelicanBobolinkWoodcockSeagullSwallowOrioleSanderlingChewinkTanagerThrushAvocetCurlewCormorantMallardWidgeonWhippoorwillFlamingoOspreyLapwingPenguinsympathetic detonationKnight Commander of St Michael and St GeorgeOtranto BarrageNimitzExaminerUnited Nations