Watch Schedule Planner
Pick a watch system and enter your crew, and see the 24-hour rotation — the watch periods, who stands each one, each watch’s strength, and the hours on duty per day.
Keeping a good watch
The watch bill is the heartbeat of a ship. Three watches on four-on-eight-off is the gold standard because it leaves real rest between turns; two watches on six-on-six-off is the fallback when the crew is thin, and the dog watches exist so the burden of the small hours rotates fairly. A rotation is only as good as the rest it protects, which is why every watch bill has to be read against the hours-of-rest rules.
Building sea-service on watches toward a certificate? Tally the qualifying days with the Sea Time Calculator.
Frequently Asked Questions
What is the traditional 4-on-8-off watch system?
It divides the day into six four-hour periods and rotates three watches through them, so each watch stands two four-hour periods a day — eight hours on, sixteen off. On the bridge these are the classic watches: 12–4, 4–8, and 8–12, morning and afternoon. Three watches is the deep-sea standard because it gives each watchkeeper a solid rest between turns.
When is a 6-on-6-off system used instead?
The two-watch, six-on-six-off system is common on smaller vessels and short-handed ships where there aren't enough qualified watchkeepers for three watches. It means twelve hours on duty a day split into two six-hour turns, which is tiring over a long voyage — which is exactly why the hours-of-rest rules matter, and why three watches is preferred when the crew allows.
What are dog watches, and why do they exist?
Dog watches split the 4–8 pm evening watch into two two-hour halves (the first and last dog watch). This makes seven watch periods in the day instead of six, an odd number, so the rotation shifts by one each day and no watch is permanently stuck with the unpopular middle-of-the-night turn. They also let the whole crew eat the evening meal in turn.
Does this planner replace the ship's hours-of-rest rules?
No. It lays out a rotation to help you visualise a watch bill, but it is not a compliance tool. STCW and the MLC set minimum hours of rest — broadly at least 10 hours in any 24-hour period and 77 in any seven days — and safe-manning requirements govern who may keep a watch. Always check any watch bill against those rules and your flag state's requirements.
A planning aid for visualising a watch bill — not a compliance tool. Always check hours of rest and safe manning against STCW, the MLC, and your flag state.