10 Message Content

  10.1 It is important that national administrations operating or planning NAVTEX services are quite clear about what sort of information shall or shall not be included in the messages.

  10.2 The International NAVTEX service shall be used for transmitting maritime safety information only and shall NOT be used as a medium for providing Notices to Mariners or for broadcasting Local Warnings. NAVTEX is essentially a medium for broadcasting information that is needed by ships to safely navigate through the NAVTEX service area of the appropriate NAVTEX station, particularly those ships on coastal passages. More detailed guidance in respect to different classes of messages is given below. Examples of the content and layout of NAVTEX messages are shown in the Joint IMO/IHO/WMO Manual on Maritime Safety Information. This publication shall be available to all personnel responsible for the drafting of messages to be broadcast by NAVTEX stations.

• 10.2.1 Navigational warnings

  • .1 coastal warnings and NAVAREA warnings (B₂ = A or L) issued under the guidance of IMO Assembly resolution A.706(17), as amended, which would be of concern to ships in the NAVTEX service area allocated to the transmitter shall be included in the broadcast. Relevant coastal warnings shall normally be repeated at every scheduled transmission for as long as they remain in force; however, if they are readily available to mariners by other official means, for example in Notices to Mariners, then after a period of six weeks they may no longer be broadcast. NAVTEX Co-ordinators shall arrange to receive NAVAREA warnings appropriate to their area for inclusion in their broadcasts. These shall be broadcast at least twice each day – to avoid overloading the broadcast time slot, they shall normally be scheduled for transmission during slots that do not include weather forecasts (see 12.4);

  • .2 a summary of navigational warnings remaining in force shall normally be broadcast each week; and

  • .3 local warnings shall not be broadcast on NAVTEX, i.e. information relating to inshore waters, often within the limits of jurisdiction of a harbour or port authority, as defined in IMO Assembly resolution A.706(17), as amended.

• 10.2.2 Meteorological warnings and forecasts

  • .1 meteorological warnings (B₂ = B), e.g., gale warnings, shall be allocated a priority of IMPORTANT (see Section 11) and be repeated at subsequent scheduled transmissions for as long as the warning is in force. These messages shall contain only the appropriate warnings and shall be separate from the weather forecasts;

  • .2 weather forecasts (B₂ = E) shall be broadcast at least twice each day. This service shall be carefully co-ordinated where transmitters are geographically close together;

  • .3 routine ice reports are normally broadcast on NAVTEX once a day; and

  • .4 ice accretion warnings (icing warnings) are normally included in gale warnings. If no gale warning is issued, they are to be treated as a meteorological warning (see 10.2.2.1).

• 10.2.3 Search and rescue information

  • .1 the NAVTEX broadcast is not suitable for distress traffic. Therefore, only the initial distress message shall be retransmitted on NAVTEX, using B₂ = D, in order to alert mariners to a distress situation, by setting off an audio alarm.

  • .2 a single authority, which will normally be a Maritime Rescue Co-ordination Centre (MRCC), shall be designated SAR Co-ordinator to input information via the NAVTEX Co-ordinator, for a NAVTEX message. The initial shore-to-ship distress-related message shall have previously been broadcast on the appropriate distress frequency prior to any related NAVTEX message being broadcast.

• 10.2.4 Piracy attack warnings

  Piracy attack warnings shall be transmitted using B₂ = D, in order to alert mariners by setting off an audio alarm. They shall be broadcast immediately on receipt and at subsequent scheduled transmissions.

• 10.2.5 Tsunamis and other natural phenomena warning messages

  Tsunami warnings, and negative tidal surge warnings shall be transmitted using B₂ = D, in order to alert mariners by setting off an audio alarm. They shall be broadcast immediately on receipt and at subsequent scheduled transmissions.

• 10.2.6 Pilot and VTS service messages

  Technical subject indicator character B₂ = F, is only to be used for broadcasting temporary alterations, movement or suspension to pilot or VTS services. This category is for the information of all ships and is not to be used for specific instructions to individual ships or pilots.

• 10.2.7 No messages on hand

  When there are no NAVTEX messages to be disseminated at a scheduled broadcast time, a brief message shall be transmitted to advise the mariner that there is no message traffic on hand. Technical subject indicator character B₂ = Z is to be used to announce "NO MESSAGES ON HAND".

• 10.2.8 Use of abbreviations

  Common examples of abbreviations used in the international NAVTEX service are contained in the Joint IMO/IHO/WMO manual on Maritime Safety Information.

• 10.2.9 National NAVTEX services

  Transmissions on 490 kHz or 4209·5 kHz, may simply repeat the messages broadcast over the International NAVTEX service but in a national language, or they may be tailored to meet particular national requirements, for example by providing different or additional information to that broadcast on the International NAVTEX service, targeted at recreational vessels or fishing fleets.