Lesson 1 of 7 · 2 min
MAIB — Marine Accident Investigation Branch
The MAIB investigates marine accidents involving UK-flagged vessels or accidents in UK waters involving any vessel. The Merchant Shipping (Accident Reporting and Investigation) Regulations 2026 set out the reporting requirements. They came into force on 15 May 2026 and replaced the 2012 Regulations; the MAIB's guidance is MGN 564 (Amendment 2).
| Accident Category | Examples | Notification Timeline |
|---|---|---|
| Very Serious Marine Casualty | Total loss of the ship, a death, severe damage to the environment | As soon as possible, by the quickest means available — phone the MAIB 24-hour line |
| Marine Casualty | Serious injury, person lost overboard, material damage, collision or grounding with damage, ship unfit to proceed, breakdown needing a tow | As soon as possible, by the quickest means available |
| Marine Incident | Near-miss collision, loss of steering in a fairway | As soon as possible, by the quickest means available |
See it
MAIB: classify, then notify
Classify the accident, then notify: every category goes to the MAIB as soon as possible, by the quickest means available.
Accident— then notify the MAIB:
As soon as possible
by the quickest means available
- Very Serious Marine Casualty
- Marine Casualty
- Marine Incident
Very Serious Marine Casualty
- Definition
- A marine casualty involving the total loss of the ship, a death, or severe damage to the environment
- Examples
- Total loss of the ship, a death, severe damage to the environment
- Notification timeline
- As soon as possible, by the quickest means available — phone the MAIB 24-hour line
How to notify
The master (or, if the master has not survived, the senior surviving officer) and the owner — as soon as possible, by the quickest means available.
After a casualty
Preserve the evidence: charts, log books, recorded data and VDR data saved at once.
Do not disturb the scene until the MAIB investigator has attended, unless doing so is necessary:
- to prevent a further casualty
- to assist the injured
- to prevent serious pollution
Failing to preserve evidence is an offence.
Very Serious Marine Casualty: As soon as possible, by the quickest means available — phone the MAIB 24-hour line.
Schematic · Merchant Shipping (Accident Reporting and Investigation) Regulations 2026 and MGN 564 (Amendment 2) as given on the module sheet · check the current MAIB guidance
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