Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Office of the Chief of Naval Operations
CABLEGRAM SENT 19th June EWC
To Opnav, Washington. Serial No. 9753.
Prep. by M-1 C of S
9753. Your 7322 and my 9472. Original plan for laying mines in area (A) provided for three systems of mines each system consisting of three rows of mines laid at 80 feet, 160 feet, and 240 feet, respectively, below the surface. Change recommended by 9472 provides that two of these systems be laid as originally planned the third system to be laid so that all three rows of mines will be at 80 feet below the surface. This change will necessitate all of the mines for the third system having long mooring ropes. It will therefore be necessary to have eleven thousand mines fitted with 400-foot mooring ropes which mines by the original plan would have been fitted half with 320-foot and half with 240-foot mooring ropes.
Modified plan for Area (A) requires mines as follows:-
5 rows of mines at 80 feet below surface.
2 rows of mines at 160 feet below surface.
2 rows of mines at 240 feet below surface. 06019
Source Note: Cy, DNA, RG 45, Entry 517B.