Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Rear Admiral Henry B. Wilson, Commander, United States Naval Forces Based in France
CABLEGRAM SENT August 18, 1918. CMB
Comfran Brest 5106
5106. A large part of success of convoy system depends on continuously and promptly following positions and intentions of submarines and frequent diverting of convoys away from dangerous area. Please forward a chart of submarine activities between parallels of Ushant and Finisterre showing tracks of all submarines assumed to be in this area between noon of 12 August and noon 19 August. Accompanying letter should give all details known to you regarding these submarines and methods by which positions and information were obtained. Particularly important that such position be marked by two time groups which indicate minutes when information was taken and available. For instance positions given by directional would be marked with time directional was taken also with time when information was decoded and placed on chart. Other information should be marked with time it was available. Use G.M.T. Foregoing chart will be checked with similar information available here. 5106.
Source Note: Cy, DNA, RG 45, Entry 517B.