The use of T&P NM information is considered an essential part of keeping navigational charts up to date. 

Most PRIMAR nations have included T & P NMs in their ENCs. Where this is the case, the ENCs are up-to-date, and therefore, no additional information layer is necessary.


PRIMAR statement on AIO


According to the IHO, more member states have indicated that their T & P NMs will be included in their ENCs by 2015.

In order to inform the users about the status of production of T&P notices in the ENC update files, PRIMAR and IC-ENC have collected information from the individual HOs distributing ENCs through the RENCs.

The following link gives an overview of T&P NTMs ENC updating production status for each nation.

Temporary (T) and Preliminary (P) notices

ENC cells require updating to include details published in paper chart Notices to Mariners. These are in two forms:

  1. Chart Correcting Notice to Mariners (NTM)
  2. Temporary and Preliminary Notice to Mariners (T&P NTM)

Not all ENC producers include T&P NTMs in their ENCs. As for those who do include T&P, there are several different practices:

  • Some produce T&P according to their NTM
  • Some produce T and not P
  • Some produce P and not T
  • Some produce T&P if considered necessary, case by case assessment

Previously, Annex B of the IHO standard S-65 provided guidelines for encoding T&P ENC updates. Recognizing the importance of adding T&P NMs in ENC updates, IHO incorporated those guidelines in S-57 Appendix B.1, Annex A in October 2011, resulting in the removal of guidelines from S-65 in April 2012.
The guidelines identify key principles for ensuring appropriate temporary and preliminary ENC Updates.

A new T & P survey was conducted in 2013 by IHO. The report Status of T-P ENC Updates presents the consolidated results of both 2011 and 2013 surveys.