Maritime navigation
A notice to mariners is an official publication that informs vessel operators about changes affecting safe navigation, including alterations to charts, buoys, lights, depths, regulations, and hazards. Hydrographic offices and naval authorities issue notices at regular intervals, allowing mariners to correct paper charts and update electronic navigation data between editions.
A notice to mariners provides authoritative corrections and warnings needed to keep nautical charts and publications current. Typical entries describe new, moved, damaged, or discontinued aids to navigation; changes in depths, dredged channels, wrecks, cables, pipelines, offshore structures, and restricted areas; and amendments to sailing directions or maritime regulations.
The notice may identify a chart number, geographic position, feature, and effective date, often supplying replacement text or a small chartlet. Some information is temporary or preliminary, while permanent changes are incorporated into later chart editions. Notices complement, rather than replace, navigational warnings, which communicate urgent dangers through radio and other rapid channels.
The underlying objective is risk reduction: a chart is a managed record of conditions and surveyed information, not a guarantee that every feature remains unchanged.
Mariners apply a notice by matching its geographic area and product number to the charts and publications carried for the voyage. On paper charts, the correction is entered in ink or pencil according to the issuing authority’s instructions, while the notice is recorded in a correction log so inspectors can verify the chart’s history.
Electronic navigational charts are updated through official data services or authorized distributors; the navigator must confirm that the correct cell, edition, and update sequence have been installed. The International Convention for the Safety of Life at Sea requires ships subject to its chart-carriage rules to carry adequate and up-to-date nautical charts and publications.3
Good practice also includes checking local port information, notices received after sailing, and the vessel’s intended route rather than assuming that a general update covers every operational detail.
National hydrographic offices publish notices for waters under their charting responsibility, while naval authorities publish products covering international routes and foreign regions. The United States publishes weekly corrections through the National Oceanic and Atmospheric Administration and separate maritime-safety information through the National Geospatial-Intelligence Agency.
Comparable services include the United Kingdom Hydrographic Office’s Admiralty Notices to Mariners and Canada’s Notices to Mariners, each organized around national charts, publications, and maritime jurisdictions.12 The International Hydrographic Organization promotes common standards for hydrographic data, charting, and exchange, but publication responsibility remains primarily national.
Because a voyage can cross several jurisdictions, bridge teams often consult more than one service and distinguish coastal authority notices from ocean-wide navigational warnings.
Notices to mariners also preserve a detailed audit trail of changing coastlines and maritime infrastructure. A notice can record a buoy’s temporary removal, a light’s altered characteristic, a newly reported obstruction, or the discovery that a published depth requires further examination; such entries may later be cancelled, superseded, or absorbed into a new chart edition.
The term covers several products rather than one universal format. A weekly notice may contain permanent chart corrections, temporary and preliminary information, corrections to sailing directions, and cumulative indexes. Some authorities issue local or port notices in addition to national publications, especially for dredging, construction, and temporary traffic schemes.
Digital navigation has not eliminated the underlying duty to update: electronic charts can display a current compilation while still requiring official updates, appropriate scale selection, and prudent interpretation of survey quality and source information. Standards from the International Hydrographic Organization help make these data exchanges consistent across systems.
Publication names, update procedures, and chart-carriage requirements vary by issuing authority and vessel type; mariners should use the official service responsible for the waters and products concerned.
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