United States Fleet Anti-Submarine Instructions


6000 GENERAL 6-1 -- 6-6
  6010 Escort Communications 6-1
  6020 Orders and Instructions 6-1
  6030 Communication Plans 6-1
  6040 Intra-Communications Methods 6-1
  6050 Radio Guards - All Areas 6-1
    6051 Primary Secondary Frequencies 6-1
    6052 International Distress Frequency 6-1
    6053 Voice Frequency 6-1
    6054 Ship to Shore Frequencies 6-2
    6055 Port Waves 6-2
    6056 Detailed Instructions 6-2
  6060 Radio Direction Finders 6-2
  6070 Homing Procedure 6-2
    6071 When to Use 6-2
    6072 Relieving Escorts 6-2
    6073 Enemy Interception 6-2
    6074 Procedure "C" 6-2
  6080 Radio Call Signs 6-3
    6081 Assignment of Call Signs 6-3
    6082 Escort Radiophone Calls 6-3
    6083 Convoy Suffix Letters 6-3
    6084 Aircraft Call Signs 6-3
    6085 British Aircraft Call Signs 6-4
  6090 Observance of Radio Security - Exceptions Thereto 6-4
    6091 Radio Silence 6-4
    6092 Transmissions During Periods of High Visibility 6-4
    6093 Choice of System of Communications 6-4
    6094 Replies to Shore Establishment 6-4
    6095 Plain Language 6-4
    6096 Radiophone Voice Code 6-4
    6097 Voice Code Table 6-5
    6098 Visual Communications 6-7


United States Fleet Anti-Submarine Instructions

Part VI



  1. Escort communications shall be in accordance with USF 70 series, and Fleet and Force communications Plans except as modified hereinafter. For the benefit of non-holders of that publication the salient points that non-holders "need to know" are included herein.

  1. Orders and instructions issued in communication publications of the United States Navy Department and the Admiralty are the basis for escort of convoy communications. Attention is particularly invited to the fact that combined or limited combined publications and procedures are to be used as applicable between allied ships of different nationalities.

  1. Communication plans for any particular escort organization are effective concurrently with the organization of the escort.

  1. Although visual is the primary method of intra-communication in the escort group, the escort group communication plan should provide for the following:
    1. A simple voice code for use on VHF and TBS.
    2. Schedules and frequencies to be guarded by all units of the task group.
    3. Communication guard diagram.
    4. HF/DF frequency guard plan and procedure.
    5. Relief fighter direction duty.
    6. Radar guard plans and doctrine.

  1. Radio Guards - All Areas.
    1. If the Escort Commander does not specify some frequency, 2410 kcs (key primary, radiophone secondary) shall be guarded by each support escort ship in lieu of the task organization frequency as set forth in USF 70 series. If changed the Convoy Commodore must be notified, as under certain conditions set forth in War Instructions for Merchant Ships, the convoy sets intercept watch on this frequency. Support groups operating with escorts should set watch on escort group frequencies and on air cover frequency when engaged in support operations.
    2. One ship of the escort (preferably the Escort Commander) shall guard 500 kcs. Aircraft assigned to cover unescorted ships shall guard 500 kcs if practicable.
    3. All ships of the escort which are equipped to do so shall guard the appropriate very high frequency set forth in the convoy communication plan (In LantFlt, 72.5 mcs.).


    1. Escort ships need not guard constantly ship to shore frequencies. For delivery of traffic to shore the Escort Commander shall utilize any of the shore stations listed in DNC 5, or in other standard U. S. Navy communication publications, or those of the Sea Frontiers.
    2. Local area frequencies, where established as "Port Waves", shall be guarded by one ship of the escort when within a radius of 100 miles of the port.
    3. Radio guards are maintained by ships of the convoy, or duly assigned guardships on 500 kcs., and BAMS broadcasts, in accordance with detailed instructions contained in War Instructions for Merchant Ships. In addition, a radio telephone frequency is also guarded by ships of the convoy appropriately equipped in accordance with the Convoy Communications Plan. This frequency shall be common to escorts and ships in convoy.

  1. Radio Direction Finders.

    If the tactical situation warrants it, the Escort Commander shall establish direction finder watches by ships of the escort and the convoy, for purpose of radio intelligence, to the limit of the availability of the personnel and apparatus and shall further provide means of receiving such information expeditiously.

  1. Homing Procedures.
    1. When aircraft are unable to locate escort promptly direction finders of escorts or planes may be utilized to effect rendezvous using either of the following procedures:
      1. Procedure "A" (Atlantic Only):

        Aircraft using air coverage frequency 2410 or 3000 kcs. as currently in use requests the Escort Commander to transmit on 385 kcs. by appropriate operating signals (Q signals). Aircraft homes on this frequency breaking transmitting ship as soon as bearing has been determined:

        CAUTION: As enemy submarines can take more accurate bearings on frequencies under 2000 kcs. than on higher frequencies this procedure should be used only as a last resort and never if escorts can utilize procedure "B".
      2. Procedure "B" (Atlantic Only):

        Aircraft using appropriate operating signals (Q signals) requests escort to take bearings on aircraft transmissions on 385 kcs. The Escort Commander takes bearing and transmits bearing on air coverage frequency 2410 or 3000 kcs. as currently in use, utilizing MCW or voice.

    2. When relieving escorts are unable to effect rendezvous, the relieving group should establish communications on the escort group frequency and obtain bearings on the escort group utilizing appropriate operating signals and escort group frequency if practicable. If the escort group is not fitted with HF/DF (or distances concerned are greater than ground wave of 2-3 mcs.) a procedure similar to Procedure (B) above should be used.
    3. It must be constantly remembered that some, if not all enemy submarines are equipped with HF/DF's and that when so equipped any radio transmission on the part of the convoy or escort may serve as a homing beacon for the enemy.
    4. Procedure "C":
      1. When aircraft are unable to locate an independent merchant ship to be escorted, the aircraft shall transmit an encrypted "Not Met" report to the base. This report should be sent upon completion of first circuit of the search plan.


      1. If the operational authority considers that homing procedure should be carried out, the aircraft will be notified. At the times directed by the operational authority, the aircraft shall transmit for two (2) minutes on 385 kcs., the war radio call sign of the ship to be escorted followed by the letter "A" and a number indicating the numeral relief of the aircraft, i.e., "A1, A2," etc.
      2. The Merchant Ship will break radio silence, transmit her war radio call sign on 375 kcs., and give the DF bearing on the aircraft. Ordinary "Q" operating signals will be employed. The naval authority ordering air cover for an independently routed merchant ship shall advise the vessel concerned by BAMS message of the estimated time of arrival of aircraft and shall direct ship to maintain watch on 385 kcs,. beginning at a specified time.

  1. Radio Call Signs.
    1. All merchant ships in convoy use convoy radio call signs as contained in WIMS 3, Article 58.
    2. Escort and support vessels shall use convoy radio signs composed of the appropriate convoy radio distinguishing group plus a CW or a voice suffix. Convoy radio distinguishing groups are assigned at the convoy pre-sailing conference and are included in the convoy sailing telegram for the information of all who need to know. Suffixes, used in conjunction with the convoy radio distinguishing group, are as follows:
      Commodore CHIEF D1
      Senior Officer of Escort BOSS D6
      Escort Vessels (collective) GANG D7
      Individual Escort and Support Vessel Last digit of hull number preceded by BUG *
      Senior Officer of Support Group FOREMAN D8
      Support Group (collective) MOB D10
      Escort Carrier No. 1 NEST D1A
      Escort Carrier No. 2 COTE D1B
      Escort Carrier No. 3 COX D1C
      Escort Carrier No. 4 SACK D1D
      A/A Cruiser CRACKER D1P
      * Individual escort and support vessels shall use CW calls from DNC3.
      Example: (Convoy radio distinguishing group AB has been allocated)
      Senior Officer of Escort: Voice = "ABLE BAKER BOSS"; CW = "ABD6"

    4. The convoy CW suffix letter D is invariably assigned to the main body of the convoy. The convoy suffix letters, E, H, I, K, O, Q, S, T, and X are reserved for allocation to sections joining or breaking off from the main body of the convoy. The letter D where appearing in the CW suffix column of the above table is replaced by the appropriate section suffix letter for convoy section communications by CW. For convoy section voice communications, the section suffix letter, spoken phonetically, is inserted between the convoy radio distinguishing group and the voice suffix.
    5. Aircraft engaged in convoy operations shall use convoy radio call signs composed of the appropriate convoy radio distinguishing group plus a suffix composed of a letter or a numeral-letter combination (the flight number may be added, if necessary, in order to prevent confusion) as follows:
      Covering Aircraft (collective) VICTOR V (RPM 2002)
      Commander of Covering Aircraft ZERO VICTOR 0V
      Officer Controlling Flight ZERO ZERO VICTOR 00V
      Plane Number One ONE VICTOR 1V
      Plane Number Two TWO VICTOR 2V


      (Flight 66 covering convoy to which convoy radio distinguishing group AB has been allocated.)

      Covering aircraft (collective): Voice = "ABLE BAKER VICTOR (SIX SIX)"; CW = "ABV (66)"

    1. A complete list of convoy radio call signs including British aircraft calls for combined use is contained in BUSCI, Article 5050.

  1. Observance of Radio Security - Exceptions thereto:
    1. Except to forward traffic essential to the accomplishment of an assigned task, which it is impracticable to transmit by other means, radio silence shall be observed by mobile units unless restrictions are further relaxed by the OTC.
    2. Radio transmissions during periods of high visibility on frequencies higher than 50 mcs may be considered tantamount to visual for security purposes.
    3. The enemy will attempt to gain information from our use of rapid communications through traffic analysis, cryptanalysis, or tracking. Therefore rapid communications subject to enemy interception shall not be used when other more secure methods will serve. When communications subject to interception must be used, that method or means most difficult to intercept shall be selected.
    4. The Mobile Naval Establishment is authorized to disregard instructions received from shore activities, even if of higher authority, to reply or report despatch, if the sending of the despatch reply or report is prejudicial to the mission or is contrary to communication restrictions currently effective.
    5. The use of plain language by radiophone or key in radio despatches is restricted to those situations, chiefly of a tactical nature, wherein immediate action is essential, and in which any delay incident to encryption and decryption cannot be tolerated. This decision is acceptable only when the gain in speed outweighs the loss in security. It must be assumed that the enemy will make every effort to intercept and evaluate all radio traffic. High frequency has been so widely used in escort operations that enemy submarines may be expected to listen on the frequencies concerned.
    6. The voice code (Article 6097) with the exception of those words marked with a (U) is common to both British and U. S. Forces using either A. C. I. (CB04234) or F. T. P. 223 and may be used by forces of one nationality and should be used when forces of different nationalities are cooperating. A blank column is provided for optional assignment of code words not appearing in the first column by the Escort Commander for intra-escort use in order to obtain some measure of security. Extracts of this code may be made for bridge and aircraft without further authorization.


ZEBRA ZEBRA   Reference point - the center of the convoy front.
BLUEBELL   Bearing (True)
MICKY   Distance (Miles unless otherwise stated)
CATSPAW   Course (True)
CHERRY   Convoy Speed
CHOCOLATE   Best Possible Speed
PINK   2
GREY   5
BUFF   6
RED   7
BLUE   0
JET   00
PUCE   000
GOLD   Dummy
QUIZ   Am investigating contact in (indicate position relative to convoy)
LOUSY   Suspicious ship in sight
BEETLE   Have obtained radar contact believed submarine. Proceeding to investigate. Bearing .... Distance ..... My position .....
TANTIVY   Submarine in sight (to be followed by approximate position from ZZ).
REDGRAVE   Submarine believed to be in (indicate position relative to convoy).
PRESTO   Submarine has dived.
HANGOVER   Attacking with depth charges.
TOASTY   Torpedo approaching or has passed from bearing ..... (or indicate position relative to convoy).
STELLA   Investigate state of ship and report.
GEORGETTE   Pick up or take off crew of ship which has sunk (or of ship indicated).
TABBY CAT   Resume your station on the screen immediately or by .....
JOSEPHINE   Take up or remain in night screening position.
CELLOPHANE   Take up or remain in day screening position.
DRAGONFLY   Take up or remain in picket station (extended screen), indicate station if desired.
LADY BIRD   I am resuming my station.
HONEY BEE   If not in contact, rejoin.
CATCH PENNY   Close the convoy at full speed to give the best A/A support.
DANDELION   Ship(s) addressed proceed on course ..... to a distance ..... to search for a submarine detected by D/F.
SWITCH   Shift HF/DF receiver to column ..... on which frequency a submarine has been heard transmitting.



PATRICK   My task is A/S sweep but if you have an urgent commitment for me I will remain with you.
RECOIL   Return for further instructions at time indicated.
DONKEY   Surface ships keep at least three miles clear of a danger area established in position ..... at time ..... for a period of fifteen minutes.
SERPENT   Search for (damaged ship, straggler(s), convoy, escort, etc., specified) on bearing (True).
BOSS   Escort Commander
MOANER   Straggler.
SHEPARD MOANER   Round up straggler.
BLONDIE   Drop flare in present position.
DARKIE   Do not illuminate or cease illumination.
CRUNCHIE   Escorts carry out operation OBSERVANT.
ZOMBIE   Escorts carry out operation ZOMBIE.
BINGO   Escorts carry out operation BINGO.
MARSHMALLOW   Torpedo track sighted.
BUTTER BALLS   Attack at night expected.
GRAVEYARD   Am about to, or have dropped smoke float (day) or flare (night) near last sono-buoy position giving hydrophone effect.
BARRYMORE   Have sono-buoy contact (Note: When preceded by NEGATIVE - means "Have lost sono-buoy contact.")
HUMPTY-DUMPTY (U)   Contact.
WASHRAG (U)   Air.
PADDY (U)   Surface.
MUMBO-JUMBO (U)   Sonar.
SHILLY-SHALLY (U)   Emergency 45° turn to starboard.
PLASTER-PARIS (U)   Emergency 45° turn to port.


        (Using Code Word SKYTRAMP for Indicating Sectors)
      Example: Course 015° is spoken
      NOTE: Report all bearings as letter plus number; never minus.
      The center of the circle is the center of the convoy front, unless otherwise designated.

      All bearings and distances are to be encoded, with following two exceptions:

      1. Radar and Sonar Contacts in plain language.
      2. Position at sea - Bearing and distance from a daily reference position are stated in plain language. The same reference position is never used twice. Position with reference to a geographical landmark is never given in plain language.

    1. During darkness and low visibility, visual communications except for recognition and emergency identification signals shall not be used unless absolutely necessary.


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