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Rear Admiral Henry B. Wilson, Commander, Patrol Force, to Patrol Force

Upon Receipt of This, Destroy Confidential Instructions Dated 17 April, 1917.1


Confidential                    U. S. S. OLYMPIA, Flagship,

  17 May, 1917                    




Subject: Instructions to vessels of PATROL FORCE

     1. Patrol Commanders will patrol to the best advantage the areas assigned, with the view to safeguarding Transatlantic shipping and destroying enemy vessels sighted.

     2. Make every effort to facilitate the passage of vessels through the patrolled area.

     3. From sunset to sunrise darken ships and station lookouts. From daylight to dark station lookouts both aloft and on deck.

     4. At all times of the day and night such portion of the battery to be manned and ready for use as is necessary to open fire instantly on a submarine sighted on any bearing.

     5. Visual signals will not be used at night except in cases of emergency, and will then be restricted to the use of blinker tube if possible.

     6. Searchlights will not be used for search, but to illuminate a target already definitely located, and they should be turned off immediately when the target has disappeared.

     7. Recognition signals as directed.

     8. Radio: Every precaution shall be taken to ensure that unnecessary radio messages are not sent, and messages when sent should be as brief as possible. Use land lines and cable for communications rather than radio.

     9. Consider any submarine hostile unless it is definitely known that our submarines are operating in the locality.

     10. Attention is invited to Intelligence Bulletin No. 1, United States Fleet, “Notes on defense against Submarines.”2

     11. Every effort shall be made by Squadron Commanders to further gunnery training particularly in the cases of vessels newly commissioned or with inexperienced crews.

     12. The Patrol Force is charged with the destruction of derelicts which menace navigation. Squadron Commanders will locate and destroy dangerous derelicts within their areas. They are authorized to call upon the Commandants of Naval Districts for assistance when necessary.


     13. The search for raiders is of such character as to require special methods, and the following instructions are issued to vessels of this force for guidance in such operations.

     14. Vessels of the Force will be sent on search by direct orders of the Patrol Force Commander.

     15. RADIO. While on search use radio only in emergency. Do not answer calls except in reply to specialized secret calls. Make no acknowledgement unless message so directs. Be prepared at all times for message-sent broadcast.

     16. Keep smoke at a minimum.

     17. Report to Force Commander when search of the area has been completed, and unless previously directed otherwise, await instructions.

     18. The area to be searched and one of the following plans of search will be defined in the order. If an area is to be searched by more than one vessel, all the vessels will be directed to rendezvous at a given time and place. The Senior Commander at the rendezvous will give necessary instructions.

     19. PLAN A.   Search area in the east and west direction beginning search on northern side of area.

          If the distance is stated in the order, this will signify distance between lines run (east and west) for one vessel, or the distance between ships when more than one vessel is searching.

          PLAN B.   Same method as PLAN A, except begin search from the southward side of the area.

          PLAN C.   Search area in a north and south direction, beginning the search from the westward. The method of procedure when the distance is given in the order to be similar to that outlined in PLAN A.

          PLAN D.   Same method as PLAN C, except begin search from the eastward.

          PLAN E.   Search area using such method as the Commander or Senior Commander (if more than one vessel) deems best.

     20. In the above methods, in beginning the search run the first line at a distance from the side of the rectangle equal to one half the distance ordered, and turn at one half the distance from the end.

     21. Speeds at night to be such that advance from sunset to sunrise will not exceed the distance named in the order. Economize fuel at night.

     22. While on search all friendly ports may be considered available for fueling.

H. B. WILSON                 


Addenda to Commander Patrol Force Confidential Instructions dated May 17, 1917.

     Paragraph 14 (a)    Despatches with the word STEAM (uncoded and preceding the cipher indicator) contain orders to proceed to sea on urgent duty, and preparations for sea will begin immediately upon their receipt.

     Paragraph 20 (a)    Nothing in the foregoing is to be construed as limiting the initiative of the officer conducting the search within his area, or to prevent his departing from the assigned plan upon receipt of reliable information such as may come from intercepted vessels.

H. B. WILSON                 

Copies to:

C-in-C [Henry T. Mayo]                6

Squadron Comdrs       12

Commanding Officer, OLYMPIA [Henry S. Knapp] 1

Comdts Naval Districts One to Eight     1

M. S. Tisdale3


Source Note: Cy, DNA, RG 45, Entry 517B.

Footnote 1: See, Wilson to Patrol Force, 17 April 1917, DNA, RG 45, Entry 517.

Footnote 2: This document has not been located.

Footnote 3: Lt. Mahlon S. Tisdale.

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