Explanatory notes to the NtMs (per week and per chart)

To support safe navigation, the Hydrographic Service publishes the most important changes to nautical products. It does so by posting Notices to Mariners (NtMs) in the NtMs-database. You can select the NtMs per week and per chart. On this page you will find more information about the 2 forms.

Explanatory notes to the NtMs per week

The NtMs-database per week contains all Notices to Mariners, except those for nautical publications. In order to create a report per week, select the product type (ordinary nautical chart or the 1800 series) and the week number.

You will find the NtMs per week according to product type, and subsequently according to product number.

Explanatory notes to the NtMs per chart

The NtMs-database per chart contains all Notices to Mariners for charts. In order to create a report per chart, fill in the required chart number and select the week numbers.

The following applies to both types of reports:

  • NtMs only apply to editions in force, you cannot correct an edition which is cancelled.
  • You can create more than one NtMs report per product.
  • Empty chapters are indicated with 'geen' (nil).
  • At the end of the selection, 'end of selected notices' is shown.


  • Block corrections and tracings for the past 3 years can be found on the page Overview by week.
  • You cannot select nautical publications in the database. A list of NtMs in force per nautical publication is available on the page Corrections to nautical publications.
  • Chart 2017 (Suriname): notices available from 01-01-1990.
  • Chart 2023 (Caribbean Sea): notices available from 01-01-2001.
  • From 13 April 2023 (week 15), the Netherlands Hydrographic Service will no longer issue tracings for Notices to Mariners.