Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Secretary of the Admiralty Sir Oswyn A.R. Murray
4 January 1918.
From: Force Commander
To : Secretary to the Admiralty.
SUBJECT: Northern barrage.
1. Following a recent study made in this office of matters concerning the northern barrage the Force Commander has arrived at certain tentative conclusions which it is proposed to communicates as soon as possible to the Navy Department at Washington as expressing the views of the Force Commander and the policy in this work which he recommends following. Prior to submitting these tentative conclusions in their present form to the Navy Department they are forwarded to the Admiralty for their information and for the purpose of learning the Admiralty’s position and views on the various points involved.
2. It is tentatively concluded that:
(1) The new position of the barrage, the Orkney-Bergen line, as outlined by the Admiralty, is the most satisfactory one.
(2) The barrage complete from the surface to a depth of 295 feet should extend from coast to coast, except for narrow surface openings at the western end and in Norwegian territorial waters.
(3) The upper rows of antenna mines should have antennae 70 feet long. The deepest rows of antennae mines should have antennae 100 feet long.
(4) Numerous points on the Norwegian coast and especially approaches to barrage openings should be mined with deep minefields to make navigation by submerged vessels as hazardous as possible for a considerable distance around these openings.
3. It is considered that the bottom of the barrage at all points should be at the same depth. It is therefore desired before deciding to extend the depth of the U.S. portion of the barrage to 295 <ft> or to any other depth to obtain information from the Admiralty as to what they will consider doing in the British section of the barrage as regards extending it downwards. A statement of the Admiralty’s position as regards (2) of the pre<c>eding paragraph is therefore requested as early as possible so that the cutting of the plummet lines for the United States mines may not be unnecessarily delayed.
Source Note: Cy, DNA, RG 45, Entry 517B. Document reference: “28-1-1.”