Researching a maritime incident with the warning archive
Written by seahazards · updated 2026-09-24 · numbers recounted nightly
Journalists, investigators, insurers and researchers often need to know what ships were told about a place at a particular moment. The warning archive can answer that question directly, with its sources — and it is just as important to know where its answers stop.
Start from a place and a time
The point-in-time lookup takes a position, a UTC time and a radius, and lists every warning in this archive that was in force there at that moment, with when we first and last saw each one. Its first answer is a coverage statement: for each warning series with records in that sea, whether we were collecting it at the time. An empty result during a collection gap does not mean a quiet sea.
The route check does the same along a corridor: warnings in force now along each leg, and the ten-year history of what has been broadcast there. Every result has a permanent link, so the question you asked can be cited and checked by someone else.
- Point-in-time lookup — What was in force at a position and time, with coverage
- Route check — What is in force along a corridor, and its history
- Coverage — Which series are collected, since when, and the gaps
Follow a name or a place
Ship names mentioned in warnings have their own pages, listing every message that uses the name with how the reports differ. A shared name is not proof of the same vessel, and the pages say when identifiers conflict. Port pages bring together the warnings within 60 nautical miles, the port's characteristics from the World Port Index and monthly port calls from IMF PortWatch.
Related-warning pages group messages linked by explicit cancellation, or by category, sea and closeness in time and place — useful for following a drifting derelict or a long-running operation through its reissues.
- Vessels — Every ship name the warnings mention
- Ports — Ports by sea, with warnings nearby and port activity
- Related warnings — Messages grouped by cancellation or proximity
- Incident replays — Sourced timelines for selected incidents
Count carefully
The Sea Ledger gives monthly counts by sea and warning type since 1997, and the category and year archives list every message. Counts are of messages, not incidents: one danger reissued weekly for a year is fifty-two messages. The NGA archive froze in May 2024 and live collection began in August 2026, so counts in between are incomplete and are marked as such on every page.
Finally, a warning records what was broadcast, not what happened. Cancellation does not mean recovery; a position is where something was reported, not where it is. The original telegram is always on the warning page — quote that, and cite the page's permanent address.
- Sea Ledger — Monthly counts by sea and warning type
- Longest in force — Warnings in force the longest, and the longest lifetimes
- Glossary — What the telegram vocabulary means