North Sea Mine Barrage
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The North Sea Mine Barrage, also known as the Northern Barrage, was a large minefield laid by the United States Navy and Royal Navy between Scotland and Norway during World War I. The objective was to inhibit the movement of the German U-boat fleet.
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[edit] Origin of the Barrage
The idea of mine barrage across the North Sea was first proposed in the summer of 1916 by Admiral Bacon and was agreed at the Allied Naval Conference on the September 5, 1917. The Royal Navy, and in particular Admiral Beatty as Commander in Chief of the Grand Fleet, were sceptical about the value of the operation and did not feel that it justified the large logistical and manufacturing commitment required.
The United States was altogether more enthusiastic about the operation as the loss of transatlantic shipping was a major domestic concern and this plan allowed the United States to play an active part in tackling this while playing to their industrial strength and with minimal risk of American casualties.
[edit] Objectives
The objective was to prevent the German U-boat fleet from operating in the North Atlantic and preying on trans-Atlantic shipping. A similar barrage had already been placed across the English Channel which had resulted in the German U-boats diverting north around Scotland. The North Sea Mine Barrage was intended to close this alternate route.
[edit] Laying the minefield
In October 1917 the United States Navy tendered an order for the 100,000 mines necessary to lay a minefield stretching 230 miles and dangerous to a depth of 200 feet1. The mines were a version of 'antenna' mine that had only been developed in July 1917. Such was the scale of the operation that 80 million feet of steel wire was required to moor the mines to the seabed. The operation was beset with technical difficulties and delays with the final mines eventually being laid on October 26, 1918.
The design of the minefield meant that there was a theoretical 66% chance of a surfaced U-boat triggering a mine and a 33% chance for a submerged U-boat. In practice the actual odds were assessed at being closer to 20% for a surfaced U-boat and 10% for a submerged U-boat2.
[edit] Success of the barrage
As the final mines were laid only a matter of days before the end of World War I it is impossible to assess the success of the plan. It is known that three U-boats were sunk on the barrage and a further 3 are thought to have done so. This represented a return of one U-boat for roughly every $13 million spent.
[edit] See also
See USS Auk (AM-38) for a vivid journal account of problems encountered in removing the mines from the North Sea, including damage to the minesweepers while performing their task, and damage to the minesweepers during storms when mines would randomly explode in all directions around them.
[edit] Notes
- Note 1: Public Records Office ADM137/847 - Admiralty Planning Division Memo of October 23, 1918
- Note 2: Public Records Office ADM137/1962 - USN Admiral Strauss to the Admiralty October 18, 1918
[edit] References
- Log entries - Log book entries during this mission, by crewman Larkin Brown, aboard the Aroostook II