The muster list is the document an inspector looks for first, because it is the one they can check without asking anyone a question: it is either posted and current, or it is not. The requirements come from SOLAS Chapter III, Regulation 8, with detail added by Regulation 37 and your flag's own guidance. As ever, your flag state and DPA are the authority for your vessel; this is the baseline.
When it must exist
The muster list must be completed before the vessel proceeds to sea, and kept up to date after any change in crew or organisation. "We are mid-rotation" is not an exemption; it is the situation the update rule exists for.
Where it must be posted
In conspicuous places throughout the vessel, including the bridge, the engine room and the crew accommodation. One copy in a bridge folder does not satisfy a regulation whose whole point is that a crew member can find their duties from wherever they are standing.
What it must show
- Each crew member's emergency duties, per emergency type, and the station they muster at
- Who is in charge: the officer responsible for each station or group, and who leads each survival craft
- Substitutes for key persons: who takes over if the person assigned is disabled or absent
- The alarm signals for each emergency and the action crew take on hearing them
- All of it in the language or languages the crew understand. A mixed-nationality crew may need more than one.
The trap: the list that drifted
Most muster list findings are not about format. They are about drift: the laminated list on the bulkhead names a stewardess who left in March, or the new deckhand appears nowhere. Every crew change quietly invalidates the posted list, and reprinting is the chore that gets deferred. That is the failure mode to design against.
How The Muster App helps: the muster list lives in the admin panel as live data: every crew member, their station, role and equipment for each emergency type, with muster ranks covering rotation positions like Deckhand A, B and C so the list survives a crew change without being rebuilt. The hard copy muster list PDF is generated from that live data in the vessel's own rank order: print it, post it on the bridge, in the engine room and in the crew mess, and the posted list matches the working list by construction. When crew change, regenerate and repost; the drift window shrinks to the walk to the printer. Each crew member also carries their own duties and alarm signals on their phone in Muster Mate, which does not replace the posted list but means nobody is relying on it from memory.
For how the duties get exercised once the list exists, see how often drills must be run and building emergency scenarios.