An overview of Notices to Mariners and how to use them

Notices to Mariners consist of textual NMs, tracings, blocks, and notes. Textual NMs are the primary source for chart updates, while tracings and blocks provide a graphic representation for quick and accurate application. Always cross-reference tracings and blocks with the textual NM to ensure all changes are applied correctly.

Upon receiving NMs, identify affected charts and record the relevant NM number in pencil against the chart number in your paper chart maintenance record NP133A. New additions, new charts, or withdrawn charts should have their dates entered in ink as a permanent record.

Updates can be applied using tracings or NM blocks, which come in A4 or A5 sizes. Each tracing shows the chart number, new chart/addition date, and a small grid indicating the update's location on the chart (e.g., a cross in the lower left box means the update is in the lower left corner). Tracings also show previous updates.

Before applying a new update, ensure the chart contains the previous update by checking the NM number in the bottom left corner. After applying an update, use a magenta pen to write the notice number in the bottom left corner of the chart. If applying a year date, underline it to distinguish it from an NM number.

Finally, use a 2B pencil to cross through the appropriate NM number in NP133A to indicate that the update has been applied.