FAQ regarding the modernized LNMs and Light Lists Application at the NAVCEN website
https://www.navcen.uscg.gov

1. What is a Local Notice to Mariners (LNM)?
2. What is the Coast Guard Light List?
3. What is a Light List Number (LLNR)?
4. What new features will mariners see in the updated application?
5. Will the Light List be discontinued?
6. Will archived weekly LNMs still be accessible after October 2024?
7. Will historical ATON data be available on the U.S. Coast Guard website?
8. How can I request historical ATON data if it's not available online?
9. Will the data be available to the public?
10. Can I search the website app by District on the website?
11. Is a User Guide available for the application?

What is a Local Notice to Mariners (LNM)?

A Local Notice to Mariners (LNM) is an essential publication issued by the U.S. Coast Guard, designed to keep mariners informed about updates to navigational aids (ATON), hazards, and other critical maritime safety information. It ensures nautical charts remain accurate and navigation in U.S. waters is safe.
Key Details:

- Content: LNMs include changes to lights, buoys, beacons, obstructions, and dredging operations. - Update Frequency: Starting in October 2024, the LNM data used by the NAVCEN website will refresh every 15 minutes, a change from the weekly publication of the past decades.

- Digital Transition: LNMs are now available in interactive, geospatial formats for easier access by mariners.

What is the Coast Guard Light List?

The Coast Guard Light List is a comprehensive directory of navigational aids (ATON), such as lighthouses, buoys, and beacons, managed by the U.S. Coast Guard.
Key Details: - Content: The Light List provides detailed information about the light characteristics, signal patterns, and visibility range of each aid.
- Geographic Coverage: It is organized by region and covers U.S. coastal waters, inland rivers, and the Great Lakes.
- Update Frequency: Starting in October 2024, the Light List will be updated every 24 hours.

What is a Light List Number (LLNR)?

The Light List Number (LLNR) is a unique identifier for each navigational aid (ATON) in the U.S. Coast Guard Light List. It allows mariners to easily cross-reference between Light Lists, nautical charts, and LNMs.

What new features will mariners see in the updated application?

The updated digital application organizes navigation data into clusters at high zoom levels, providing a simplified view. As you zoom in, the clusters break down into smaller areas, showing individual ATON. Key features are:
• Near-real-time Data: Users will now be able to obtain Local Notice to Mariners (LNMs) updates every 15 minutes and Light List updates every 24 hours.
• GIS Display: The data will be presented through an interactive Geographic Information System (GIS) display, allowing users to explore spatial information and focus on specific areas of interest.
• API Integration (coming soon): We are planning a future Application Programming Interface (API) for users who want to integrate our data directly into their own systems.
• Users will be able to select, view, and print navigational data in an LNM customized for a very specific area if desired, or print a large area if needed.

Will the Light List be discontinued?

No, the U.S. Coast Guard will not discontinue the Light List. While the format and accessibility of the data will shift to more interactive and frequently updated digital formats, the core function remains the same. Mariners can continue accessing the data through the NAVCEN website. Light List data will be refreshed every 24 hours to ensure the most up-to-date and accurate information is available. As before, once a year, a PDF version will be published.

Will archived weekly LNMs still be accessible after October 2024?

Yes, LNMs from October 2024 and before will still be available on the NAVCEN website archives. However, beginning in November 2024, the U.S. Coast Guard will no longer archive LNMs in their traditional weekly format.

Will historical ATON data be available on the U.S. Coast Guard website?

After the new application is published (and LNMs are no longer published on a weekly basis), historical data will be available via Freedom of Information Act (FOIA) request (see below for instructions). In addition, legacy LNMs will be available in the Navigation Center website archives.

How can I request historical ATON data if it's not available online?

Mariners can request historical ATON data by submitting a Freedom of Information Act (FOIA) request. Requests should specify the type of data, location, and dates. Submit your request via the U.S. Coast Guard’s FOIA website or mail it to:
U.S. Coast Guard
FOIA Officer
Commandant (CG-611)
U.S. Coast Guard Stop 7710
2703 Martin Luther King Jr Ave SE
Washington, DC 20593-7710

Will the data be available to the public?

Yes. NAVCEN intends to release the data in GEOJASON format supporting both Light List and LNM updates, which will include all layers in the GIS application on the Navigation Center website.

Can I search the website app by District on the website?

The user will be able to query areas to an extent. For example, users can zoom out to access all LNM data for a selected area. Currently, there is no function to view LNM data for larger areas such as an entire coastline. Date filtering is not available but is under consideration.

Is a User Guide available for the application?

Yes, a user guide is in development and will be released alongside the application.

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