Admiral William S. Benson, Chief of Naval Operations to Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters
CABLEGRAM RECEIVED : May: <29, 1918.> 10230 TOH
Origin Opnav, Washington. Ser. No. 6652.
6652. Your 8503. No further real development. Before receipt of cable Department had decided that most effective defense against hostile cruiser submarine lay in proper distribution and operation of our own submarines. To accomplish this West coast and Honolulu practically stripped except few for training purposes and plans laid for operating all from certain focal operating points. These focal points are Canal Zone, Saint Thomas, Key West, Galveston or Tampico, Capes of Chesapeake, New York, Long Island area, Boston, and Halifax. Except for Galveston and Halifax distribution is in effect now and operations can begin at once upon receipt of authentic information of presence of hostile submarine. In addition, submarine construction hastened and assembly on Atlantic Coast of new submarines commissioned has been directed. In general remainder of defense plan is simple.
1st. Merchant Shipping: the plan is for oversea convoy and escort for east bound: diversion for individual West bound ships; protection by one five inch gun aft and smaller gun forward; diversion of ships for the entire Caribbean Sea and Gulf Coast, ships sailing by day close in shore under protection of district craft or at night by off shore diverted route; individual sailings to be adhered to unless the situation should be so acute as to warrant convoy method which would not be probable.
2nd. District defense; The location of a few guns at essential focal shipping points; purely defensive mine field of limited area and nets at focal points; no offensive mines; air patrol and listening stations at few focal shipping points; adequate sweeping service at focal shipping points; very limited district escort out for ships by chasers and destroyers; the retention of nine destroyers for this purpose; the distribution of a few coast guards or yachts at focal shipping points to answer rescue calls.
3rd. Control warnings; vested in the Office of Naval Operations except such as require immediate action and are authentic; initiative for local offensive vested in Commandant pursuant to a general policy laid down by Department; War warnings not to be given out unless pre-sumption is that they are authentic. 20029. 6652.
Source Note: Cy, DNA, RG 45, Entry 517B