MLC Hours of Rest: A Practical Guide to Managing Crew Fatigue and Compliance

Fatigue is one of the few risks at sea that is both completely predictable and routinely under-managed. Tired people make mistakes, and a tired bridge or engine watch is a safety problem long before it is a compliance problem. That is why hours of rest are written into international law - and why "hours of rest" is one of the first things a Port State Control (PSC) inspector asks to see.

For operators, the challenge is rarely understanding the rules. It is keeping accurate, defensible records across a whole crew, on contracts that run for months, in a way that flags a problem before it becomes a violation. Here is how to think about it.

What the rules actually require

Two regimes set the limits, and they overlap. Under the Maritime Labour Convention (MLC) and the STCW hours-of-rest provisions, a seafarer must have:

• a minimum of 10 hours of rest in any 24-hour period, and
• a minimum of 77 hours of rest in any 7-day period.

The 10 hours may be split into no more than two periods, one of which must be at least 6 hours, and the gap between consecutive rest periods cannot exceed 14 hours. There are narrow exceptions for drills and emergencies, but the baseline is strict by design.

The catch is that these are rolling windows. A schedule can look fine on any single day and still breach the 7-day rule, or fall foul of the "no more than 14 hours between rests" clause. Checking that by hand, across dozens of crew, is exactly the kind of task humans do badly.

Why paper and spreadsheets fail

Most fatigue problems are not deliberate; they are arithmetic. Paper rest-hour forms and spreadsheets fail in predictable ways:

• they are filled in after the fact, often from memory,
• they are checked - if at all - only when something has already gone wrong,
• they do not flag a rolling-window breach until an inspector finds it,
• and they are easy to "tidy up" in a way that destroys their credibility.

A record that only tells you about a violation after it happened is not managing fatigue. It is documenting it.

What good looks like

A proper work and rest-hours module validates the schedule against the MLC and STCW limits automatically, in real time, and flags violations for the master as they develop - not weeks later. That changes the conversation from "explain this breach to the inspector" to "rebalance this watch before it breaches."

The strongest implementations also draw on data the operator already holds. If the crew roster and the bridge watch rota are in the same platform, hours of rest are partly computed from the watches people are actually assigned, rather than re-entered by hand. Fatigue, scheduling and watchkeeping stop being three disconnected records and become one picture.

Fatigue is a management problem, not a form

It is worth being honest about the goal. The point of hours-of-rest records is not to pass an inspection; it is to run a vessel where people are rested enough to be safe. Compliance is the by-product of doing that well. The right tooling supports the management decision - who is approaching their limit, which watch pattern is unsustainable, where you are one port call away from a problem - and produces the inspection evidence as a side effect.

What to ask

If you are reviewing how your fleet handles fatigue, the questions are simple:

• Are rolling 24-hour and 7-day limits checked automatically, or by hand?
• Does the system flag an approaching breach before it happens?
• Do rest hours draw on the actual roster and watch rota, or a separate form?
• Can you produce defensible hours-of-rest records for PSC on demand?

The bottom line

Hours-of-rest compliance is where good intentions meet rolling-window arithmetic - and the arithmetic usually wins on paper. Validating against MLC and STCW limits automatically, drawing on the roster and watch rota you already keep, turns fatigue from a recurring inspection finding into something you actively manage. That is better for the inspection, and far better for everyone standing a watch.