Created by: Liam Turner
Last updated:
Generate a rotating day and night watch timeline, crew workload totals, handovers, off-watch time, and uncovered-watch warnings for an entered passage.
Generate a starting rota while keeping competence, fatigue, command, and legal requirements with the skipper.
A Boat Crew Watch Schedule & Passage Timeline Calculator creates a round-robin rota from entered crew names, passage duration, departure time, day and night watch lengths, minimum people on watch, handover allowance, and an optional unavailable crew member. It reports every block, passage end, individual watch hours, night hours, off-watch hours, block counts, handovers, and uncovered-watch warnings.
A rota is not a fatigue assessment. Time shown as off watch can be consumed by meals, maintenance, navigation, sail changes, seasickness, noise, motion, emergencies, and difficulty sleeping. Competence also differs: not every crew member can navigate, operate communications, manage traffic, reef, start the engine, or take command.
The generated schedule therefore supports a crew briefing rather than replacing one. RYA passage-planning guidance emphasizes crew experience and physical ability, safety equipment, the voyage plan, contingency actions, how to start the engine, how to send a distress call, onboard hazards, and who should take over if the skipper is incapacitated.
Night, landfall, restricted visibility, traffic, weather, and complex pilotage may require more qualified people than a routine offshore block. The skipper must revise the rota when conditions, health, workload, or progress change and must follow any applicable legal, race, commercial, or organizational requirements.
Crew names are trimmed and checked for duplicates. An optional unavailable person is removed from the eligible rotation but remains visible in the workload table.
Starting at departure, the scheduler chooses the day or night watch length based on the block start time. The final block is shortened to end exactly at the entered passage duration.
Eligible crew are selected in round-robin order for the entered minimum coverage. Individual watch, night-watch, off-watch, and block totals accumulate from the generated timeline.
If eligible crew are fewer than minimum coverage, blocks remain unassigned and the result is flagged red. Handover minutes are reported separately and do not extend the passage duration.
Passage end = departure + passage hours
Off-watch hours = passage hours − assigned watch hours
Total handover allowance = (watch blocks − 1) × handover minutes
Coverage requires eligible crew ≥ minimum people on watch
With one person required and alternating day/night blocks, three names rotate through the generated timeline. Total assigned watch hours equal twelve, while each person’s distribution depends on block boundaries and the night interval.
Marking one person unavailable removes them from assignments but retains zero watch hours in the table. The remaining crew may receive substantially more workload, which should trigger a wider review rather than automatic acceptance.
If two people are required on watch but only one eligible person remains, the calculator reports uncovered blocks. It does not duplicate the same person or silently lower the requirement.
Enter names only after deciding who is competent for each duty. Define skipper, navigator, radio, engine, lookout, sail-handling, and emergency responsibilities separately.
Protect realistic sleep opportunity, not just off-watch arithmetic. Consider meals, noise, motion, seasickness, weather, traffic, landfall, and workload before accepting a rotation.
Review the schedule with the whole crew and revise it underway. If fatigue, illness, weather, or equipment problems make the plan unsafe, seek refuge, stop, or change the passage as appropriate.
A watch schedule assigns qualified crew to defined periods of responsibility during a passage while other crew rest or perform other duties. This calculator rotates entered names through day and night blocks and totals workload. It does not determine who is competent, legally required, medically fit, or capable of taking command.
The calculator checks whether each block starts inside the entered night interval. It then uses the selected night or day block length until the next handover or passage end. This is a planning simplification; a custom operational rota may split at twilight, meal times, traffic areas, landfall, weather changes, or skipper instructions.
No. Off-watch time is simply passage time not assigned to the watch role. Meals, maintenance, navigation, sail handling, noise, motion, illness, childcare, anxiety, emergencies, and handovers reduce real rest. Fatigue management requires more than an arithmetic rota and should be reviewed continuously.
It means the number of eligible entered crew is below the minimum people-on-watch setting. The calculator leaves those assignments empty rather than inventing crew. The skipper must resolve the plan through qualified personnel, route or duration changes, safe stopping, or other appropriate measures before departure.
Yes. The Batch 1 interface can exclude one selected person from rotation to model illness, rest protection, or another role. That is a simple scenario. Real availability can vary by time, competence, sea state, task, and emergency duty, so the generated rota needs human review.
No. It is designed as a recreational planning aid and does not interpret work/rest law, safe-manning documents, employment rules, race requirements, charter coding, insurance, or jurisdiction-specific obligations. Commercial and regulated operations must use their applicable approved procedures, records, qualified personnel, and professional advice.
This is a recreational scheduling aid, not a competence, fatigue, medical, legal manning, commercial work/rest, command, or safe-passage determination.