Procedures for Patrolling the East Coast of South America agreed to by the British and American Naval Commanders in the Theater
CONFIDENTIAL. RIO DE JANEIRO, BRAZIL.
June 29, 1917.
PROCEDURE AGREED UPON BY COMMANDER-IN-CHIEF, U.S.PACIFIC FLEET, AND THE COMMODORE COMMANDING THE BRITISH FORCES ON THE EAST COAST OF SOUTH AMERICA AT A CONFERENCE HELD ON BOARD THE USS PITTSBURGH.
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At a conference held on board the U.S.S. PITTSBURGH on 25th June, it was decided that as soon as circumstances admit, the following arrangements will be made for patrolling the East Coast of South America.
The United States Squadron to have two ships based on Bahia which will patrol the United States designated area north of Bahia, extending the patrol to cover the Allied Traffic Lane as far North as Fernando Naronha1 and as far east as long. 20° W. Also two ships based on Rio de Janeiro which will patrol the United States designated area from Bahia south to the latitude of Rio de Janeiro, extending the patrol to cover the Allied Traffic Lane.
The British Squadron to have, if available, two ships based on Rio de Janeiro which will patrol the United States designated area from Rio de Janeiro south to lat. 30° S., extending the patrol to cover the Allied Traffic Lane. Also, if available, two ships based on the Plata2 which will patrol the United States designated area from lat. 30° S., to the latitude of English Bank,3 extending the patrol to cover the Allied Traffic Lane.
Circumstances permitting, ships will patrol two-thirds of the time, the remainder being spent coaling and refitting; the intention being to always have one ship in the specified area.
Should a reliable report be received of recent date of the presence of a raider, and circumstances are favorable, a combined search will be carried out.
The United States and British Naval Attaches will pool all information and decide what intelligence shall be broadcasted. The message will be sent by B.K.W.Code (A.F.R.Signal Book)4 through the Wireless Stations at Ascension and Falklands and the United States Man-of-War which happens to be in harbor. Each message to be repeated at least twice.
The Naval Attaches will keep each other mutually informed of the movements of their respective Squadrons.
Wireless silence is of the first importance and every effort will be made to maintain it.
The ships of the British Squadron have been instructed as follows:
“From information received, in at least one instance an enemy raider steamed up to a ship at night and suddenly switched searchlights on to her. Ships of the Squadron are not to burn searchlights at night, and if any vessel acts as described above,fire should be opened on her.”
The foregoing agreement is tentative and will not be considered to come into force until the U.S.Commander-in-Chief signals to the Senior British Officer “Patrol orders in force, (date), (time).”5
Mutual arrangements have been concluded for communication by visual signals and by wireless telegraph.
Aubrey Smith W.B. Caperton,
Commodore, Royal Navy. Admiral, U. S. Navy.
Source Note: D, DNA, RG 45, Entry 517.
Footnote 1: Fernando de Noronha is an archipelago of twenty-one islands and islets in the Atlantic Ocean some 220 miles off the coast of Brazil.
Footnote 2: That is, Rio de la Plata.
Footnote 3: English Bank has not been identified although it may have been near the Falkland Islands.
Footnote 4: This signal book has not been found.
Footnote 5: A short time after this agreement was reached, the government of Brazil agreed to join the patrol of the waters off its coast. Caperton to Navy Department, 12 July 1917, Ibid.