Hours of rest at sea: the 10-hour and 77-hour rules explained

By StratPollen Studio · Updated 5 November 2026 · 5 min read

Fatigue is one of the biggest safety risks at sea. Tired people miss things on watch, make mistakes during cargo work and get hurt. That's why international rules set minimum hours of rest for seafarers, and why every ship has to keep records of them.

This guide explains the rules in plain English, shows how to check a work pattern against them, and covers the exceptions. It's a general explainer, not legal advice: your flag state, contract or collective agreement may set stricter limits.

The basic rules

Two international instruments set the limits: the Maritime Labour Convention (MLC 2006), Standard A2.3, which covers seafarers in general, and the STCW Convention, which covers watchkeepers and those with safety duties. Under the minimum-rest rules, a seafarer must have:

• at least 10 hours of rest in any 24-hour period;
• at least 77 hours of rest in any 7-day period.

Those 10 hours may be split into no more than two periods, and one of them must be at least 6 hours long. The gap between consecutive rest periods must not exceed 14 hours.

The MLC also allows flag states to regulate by maximum hours of work instead: no more than 14 hours in any 24-hour period and 72 hours in any 7-day period. The daily figures match (14 hours of work leaves 10 of rest); the weekly ones are slightly different.

"Any 24 hours" means a rolling window

The rules don't say "per calendar day". They say any 24-hour period. So you can't only check midnight to midnight; every 24-hour window has to contain at least 10 hours of rest. The same applies to any 7-day window and the 77-hour rule.

This is why a schedule that looks fine day by day can still break the rules across two days, for example when a late cargo operation runs into an early watch.

Checking a work pattern: two examples

A pattern that works

A watchkeeper on the classic 4-on, 8-off pattern stands watch 08:00–12:00 and 20:00–24:00. If nothing else comes up, their rest is 00:00–08:00 (8 hours) and 12:00–20:00 (8 hours). That's 16 hours in two periods, well over the minimum.

Now add cargo work from 13:00 to 17:00. Rest becomes 00:00–08:00 (8 hours), 12:00–13:00 (1 hour) and 17:00–20:00 (3 hours). Only two periods can count toward the 10 hours, so take the 8-hour and 3-hour periods: 11 hours, one of them over 6. Still compliant, but with little margin.

A pattern that doesn't

Another officer stands watch 00:00–04:00 and 12:00–16:00, but also works cargo 06:00–11:00 and 18:00–22:00. Their breaks are 04:00–06:00, 11:00–12:00, 16:00–18:00 and 22:00–24:00. That adds up to 7 hours, the longest break is only 2 hours, and they've had no period of at least 6 hours. This breaks the rules several ways at once.

Exceptions

The rules recognise that ships sometimes face situations that can't wait:

• Emergencies. The master can require any hours of work needed for the immediate safety of the ship, people on board or cargo, or to help other ships or people in distress. Once things are back to normal, the master must make sure affected seafarers get an adequate period of rest.
• Drills. Musters and fire, lifeboat and other drills should be run in a way that disturbs rest as little as possible and doesn't cause fatigue.
• Call-outs. When someone on call, such as an engineer on an unmanned engine room, is called out during a rest period, they should get compensatory rest.
• Flag-state exceptions. Under STCW, flag states may allow limited exceptions for watchkeepers, such as a weekly minimum of 70 hours, or rest split into three periods (one of at least 6 hours and neither of the others under 1 hour). These are restricted in how long and how often they can be used.

Records: why honest logging matters

Every ship must post a table of shipboard working arrangements, showing the schedule of work at sea and in port for each position. Each seafarer's actual hours of rest must be recorded, and the records are signed by the master (or someone the master authorises) and by the seafarer, who should get a copy.

These records are checked during inspections, and falsified records are treated as a serious breach. More importantly, honest records are how companies spot that a ship needs more crew or a different schedule. If the hours don't fit, the records are the evidence that something has to change.

Spotting fatigue

Rest hours set a minimum; they don't guarantee good sleep. Watch for signs of fatigue in yourself and others:

• trouble concentrating, slow reactions or forgetting routine steps;
• nodding off on watch or during breaks;
• irritability and short temper;
• headaches, heavy eyes or feeling unwell.

Some things help: keep your cabin dark and quiet during rest periods, avoid caffeine and energy drinks in the last few hours before sleep, and use short naps wisely when your schedule allows. Most of all, report fatigue to the officer on watch or your head of department. It is a safety issue, not a weakness.

Quick takeaways

• At least 10 hours of rest in any 24 hours and 77 in any 7 days.
• No more than two periods, one at least 6 hours; no more than 14 hours between rests.
• Check rolling windows, not just calendar days.
• Keep honest records and report fatigue early.