North Sea Mine Barrage - Success of The Barrage

Success of The Barrage

Supply problems and technical difficulties caused some delays. Planned additional minelaying excursions to complete the barrage were cancelled when the approaching end of hostilities was recognized upon completion of the thirteenth minelaying excursion on 26 October 1918. The design of the minefield meant there was a theoretical 66% chance of a surfaced U-boat triggering a mine and a 33% chance for a submerged U-boat. On the basis of the number of effective mines observed while sweeping the barrage, the actual odds were assessed at being closer to 20% for a surfaced U-boat and 10% for a submerged one. 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. Some contend the minefield was a major cause of the declining morale of the Imperial German Navy through the final months of the war, while others suggest Germany easily swept safe channels through the large, unguarded minefield.

The official statistics on lost German submarines compiled on 1 March 1919 credited the North Sea mine barrage with the certain destruction of four U-boats, probable destruction of two more, and possible destruction of another two.

• 19 August 1918 SM UB-12 unknown - possibly sunk by the North Sea mine barrage
• 9 September 1918 SM U-92 presumed sunk by the North Sea mine barrage area B (confirmed in 2007)
• 9 September 1918 SM UB-127 sunk by the North Sea mine barrage area B
• 25 September 1918 SM U-156 sunk by the North Sea mine barrage area A
• September 1918 SM U-102 presumed sunk by the North Sea mine barrage area B (confirmed in 2006)
• 19 September 1918 SM UB-104 sunk by the North Sea mine barrage area B
• September 1918 SM UB-113 unknown - possibly sunk by the North Sea mine barrage
• 18 October 1918 SM UB-123 sunk by the North Sea mine barrage area A

Eight more boats were known to have been damaged by the mines, and some Admiralty personnel assumed the field might be responsible for five more U-boats which disappeared without explanation.