Hydrographic notes
Standard reporting form for reporting navigational hazards, changes to maritime signalling aids, and corrections needed to charts and nautical publications.
The hydrographic note is a standard reporting form used to request information from mariners when they discover new or suspected navigational hazards, observe changes in the operation of maritime signalling aids, or consider that corrections are needed to the Maritime Hydrographic Directorate's analogue and electronic charts or nautical publications.
This navigational safety information is broadcast in the radio navigational warning and subsequently published in the Notices to Mariners.