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Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to the Office of the Chief of Naval Operations

<August 16, 1918,>      


Date:     August 15, 1918

To:       Opnav.  CS.1     Approved NCT.       No. Simben 26.


     Simben 26. Your Simben 12.2  There is always possibility but little probability of enemy capital ship passing through Straits of Dover. See page two Planning Section Memorandum Number Twenty-six which represents my view and those of Admiralty Staff.3

     Present status of North Sea Barrage as follows:-4

     Area C: British have laid two systems each consisting of three rows deep mines and are laying a double row of surface mines. The deep mines are at depths of sixty-Five, ninety-five, and one hundred twenty-five feet. They expect to complete these systems by laying mines at one hundred fifty-five and one hundred eighty-five feet by end of September but will probably not undertake third system deep mines this year. We have laid two rows mines eighty feet below surface mines three hundred feet apart. This is half specified density and one more mine laying operation will be required to complete our plans in this area. Our mines will be laid forty-three feet below surface in future operations. In view of laying of British surface mines completion of our lines may be deferred until Area A has been completed.

     Area A: We have laid eighty percent of mines as planned from eastern end area to Longitude one degree twenty minutes east. From that point to eight minutes east, twenty-eight percent. No mines yet laid west of eight minutes east Longitude.

     Area B: twelve hundred thirty-five deep mines laid by British. All of these that did not explode prematurely have been swept up owing to the fact they constituted danger to Grand Fleet and Scandinavian convoy. No mines now in Area B.

     Completion our mining operations depends on success in determining cause premature explosions. If this cause is quickly found our portion of barrage should be completed by October fifteenth or possibly earlier.

     Am urging on Admiralty importance of making complete surface barrage from Norwegian coast to Orkney Islands. Strong representations being made by Foreign Office to Norwegian Government to convince them they should mine their waters and such action would not vitiate neutrality according to accepted principles International Law.

     Admiralty Staff fully alive to importance of mining Area B but are not ready to proceed with it yet on account difficulties anticipated in handling of Scandinavian convoys which Ministry of Shipping regards as highly important. I am insisting this is secondary consideration and that primary necessity is complete barrage against surface and sub-surface craft. Hope for early decision on this basis.   03316.



Cy, DNA, RG 45, Entry 517B. The handwritten date is confirmed by the time/date stamp at the end of the cable.

Footnote 1: Sims’ chief of staff Capt. Nathan C. Twining.

Footnote 2: Simben 12 has not been found.

Footnote 4: For a map of the North Sea Mine Barrage, see: Illustrations for April 1918.

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