Explanatory Note Regarding CHS Temporary and Preliminary Notices to Mariners (NOTMAR) Practice

CHS may receive new information pertaining to navigation products from various sources. All information is assessed to determine if it is navigationally significant.

It has been CHS practice since 2010 not to produce temporary or preliminary chart corrections in Section 2 of Notice to Mariners for its paper or electronic products.

However, CHS ensures that this information is communicated to mariners in the following manner:

  1. For Temporary NOTMARs (Ts) of less than 6 months a Notices to Shipping (NOTSHIP) will be issued.
    The Canadian Coast Guard (CCG) issues Notices to Shipping (NOTSHIP) … to inform mariners about hazards to navigation and to share other important information. [See http://www.ccg-gcc.gc.ca/eng/ccg/notship for more information on NOTSHIPs.]
    NOTSHIP alerts are broadcast by radio by Marine Communications and Traffic Services (MCTS). Written NOTSHIP are issued when the location of the hazard is beyond broadcast range, or when the information remains in effect for an extended period of time.
  2. For Temporary NOTMARs (Ts) of greater than 6 months a NOTSHIP will be issued followed by a NOTMAR and an update message for ENCs.
  3. Preliminary NOTMARs (Ps) will be handled by Notices to Shipping (NOTSHIPs) and advertised in Section 2 of Notice to Mariners.  CHS will action these as a NOTMAR and through an update message for ENCs by producing an update/patch within five months following level of services (LOS). 


  • An explanation and a list of these "T" and "P" notices can be found on the CCG website at: https://www.notmar.gc.ca/publications/temp-pre/temp-pre2016-en.pdf.
  • The term Notices to Shipping (NOTSHIP) is not used outside Canada, whereas the terms Local Warning and Navigational Warning are more widely used and recognized by foreign crews. The French hydrographic office (Service hydrographique et océanographique de la marine (SHOM)) SHOM uses the term « Avertissements urgents de navigation ».
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