The Limits, Precisely Stated
Four conditions must hold simultaneously. Missing any one is a violation:
| # | Rule | The trap |
|---|---|---|
| 1 | Minimum 10 hours of rest in any 24-hour period | "Any" means rolling — not midnight to midnight |
| 2 | Minimum 77 hours of rest in any 7-day period | Also rolling — every 7-day window, not Monday–Sunday |
| 3 | Rest may be split into no more than two periods | Three short rest blocks breaches this even if the total is 10+ hours |
| 4 | One rest period must be at least 6 hours, and the interval between consecutive rest periods must not exceed 14 hours | The 14-hour interval rule is the most-forgotten of the four |
Rest is not simply "not working". Rest means a period during which the seafarer is genuinely off duty. Short interruptions — a call-out, an alarm, a brief task — break the rest period. A "rest" period broken by a fifteen-minute callout is two rest periods, and that can turn a compliant day into a violation of rule 3 or 4.
The Rolling Window — Where Violations Hide
This is the single most misunderstood mechanic, so it is worth being explicit.
The requirement is not "10 hours of rest per calendar day." It is 10 hours in any 24-hour period. Imagine sliding a 24-hour window across the timeline one hour at a time. At every position, the rest inside that window must total at least 10 hours. A schedule breaches the rule if any position fails — including windows that begin at 07:00, or 15:00, or any other hour.
The consequence is counter-intuitive and it is why manual checking fails:
Two individually compliant calendar days can combine into a non-compliant 24-hour window. If a seafarer takes most of their rest early on Monday and most of their rest late on Tuesday, the window spanning Monday evening to Tuesday evening may contain far less than 10 hours — even though both calendar days, read separately, look fine.
The same applies to the 77-hour rule across any 7-day window, which is why a fortnight of heavy port calls can breach on a window nobody examined.
Worked Examples: Compliant vs Non-Compliant
Example 1 — Compliant
A standard 4-on/8-off watchkeeping pattern:
| Period | Status | Duration |
|---|---|---|
| 00:00 – 04:00 | Work (watch) | 4 h |
| 04:00 – 12:00 | Rest | 8 h |
| 12:00 – 16:00 | Work (watch) | 4 h |
| 16:00 – 00:00 | Rest | 8 h |
Check: Total rest = 16 h ✓ (≥10). Two rest periods ✓ (≤2). Longest rest 8 h ✓ (≥6). Longest interval between rests = 4 h ✓ (≤14). Compliant — and it stays compliant on every rolling window because the pattern repeats every 12 hours.
Example 2 — Non-compliant on the interval rule
| Period | Status | Duration |
|---|---|---|
| 00:00 – 06:00 | Rest | 6 h |
| 06:00 – 21:00 | Work (cargo ops) | 15 h |
| 21:00 – 00:00 | Rest | 3 h |
Check: Total rest = 9 h ✗ (below 10). Two rest periods ✓. One period ≥6 h ✓. Interval between rests = 15 h ✗ (exceeds 14). Two violations — the shortfall and the interval. Note that even if rest had totalled 10 hours, the 15-hour work stretch alone would still breach rule 4.
Example 3 — The one that catches people: fine by day, breach across the boundary
| Day | Rest periods | Calendar-day total |
|---|---|---|
| Monday | 00:00–08:00 (8 h) and 20:00–22:00 (2 h) | 10 h ✓ |
| Tuesday | 02:00–04:00 (2 h) and 16:00–00:00 (8 h) | 10 h ✓ |
Both calendar days show exactly 10 hours. Now slide the window to Monday 08:00 → Tuesday 08:00:
- Monday 20:00–22:00 → 2 h
- Tuesday 02:00–04:00 → 2 h
- Total in that 24-hour window = 4 hours ✗
That is a serious violation, invisible to anyone checking day by day. It also breaches the 6-hour rule (no single rest period of 6 h within that window) and the 14-hour interval rule (22:00 Monday to 02:00 Tuesday is fine, but 04:00 Tuesday to 16:00 Tuesday is 12 h — while 22:00→02:00 gaps compound the fatigue picture).
This is the example to show your officers. It demonstrates in thirty seconds why "I filled in the form and each day showed ten hours" is not a compliance argument — and why rest hours cannot be reliably assessed by eye.
MLC 2006 vs STCW: What Differs
| MLC 2006 (Standard A2.3) | STCW | |
|---|---|---|
| Applies to | All seafarers on the ship | Watchkeeping personnel and those with designated safety/security/pollution duties |
| Framing | Member State fixes either minimum hours of rest or maximum hours of work | Minimum hours of rest |
| Rest limits | 10 h / 24 h and 77 h / 7 days | 10 h / 24 h and 77 h / 7 days |
| Work limits (alternative) | 14 h / 24 h and 72 h / 7 days | — |
| Division of rest | Max 2 periods, one ≥6 h, interval ≤14 h | Max 2 periods, one ≥6 h, interval ≤14 h |
The practical position: the headline numbers align, but the scope differs and a ship is commonly assessed against both. A schedule must satisfy whichever regime applies to that seafarer — which is why systems that validate against both simultaneously prevent an entire class of argument during inspection.
Emergencies, Exceptions and Compensatory Rest
The rules are not absolute, but the exceptions are narrower than they are often treated:
- Master's overriding authority. The master may suspend the rest schedule and require work as necessary for the immediate safety of the ship, persons on board or cargo, or to assist others in distress.
- Compensatory rest. Once the situation is resolved, seafarers who worked during a scheduled rest period must receive an adequate period of compensatory rest.
- Drills. Musters and drills must be conducted so as to minimise disturbance to rest periods and not induce fatigue.
- Exceptions by collective agreement. Limited departures may be permitted where authorised by the competent authority — these are formal, documented arrangements, not informal practice.
"Operational necessity" is not a general exemption. Cargo operations running long, a port call under commercial pressure or a short-handed department are planning problems, not emergencies — and recording them as emergencies is itself a finding waiting to happen.
Records That Survive Inspection
Rest-hour records are examined routinely by Port State Control — and, since seafarers' employment and living conditions sit among the leading deficiency categories, they receive real scrutiny. See our PSC detention guide for where this fits in the wider inspection picture.
- Record as worked, daily. Reconstructed records are as visible here as in any other log — identical handwriting across a month tells its own story.
- Endorse properly. Records are signed by the master or authorised person and by the seafarer, with a copy given to the seafarer.
- Post the schedule. The table of shipboard working arrangements should be posted in an accessible place, in the working language and in English.
- Do not "correct" toward compliance. A record altered to show compliance that did not occur converts an administrative breach into a falsification issue.
- Show the compensatory rest that followed any emergency deviation — the deviation is defensible; the missing compensation is not.
Fixing the Causes, Not the Record
Persistent violations are almost never a recording problem. They are a manning, planning or workload problem that the record is faithfully reporting. Where they cluster:
- Port calls — cargo operations, surveys, inspections and bunkering stacked onto the same officers.
- Inspection preparation — ironically, preparing for a vetting or PSC inspection is a classic driver of rest-hour breaches.
- Reduced manning — a single vacancy or repatriation absorbs into the same watch pattern.
- Maintenance backlogs — overdue jobs compressed into short windows. Steady planned maintenance is a fatigue control as much as a reliability one.
- Drills scheduled without regard to rest.
The management response is to see breaches early — while the week can still be re-planned — rather than at month end when the only remaining options are a violation or a false record. That is a systems question, and it is the honest case for automating the calculation: not to make the numbers look better, but to surface a developing breach in time to prevent it.
Catch the breach while you can still prevent it
Volaxin validates rest hours against MLC 2006 and STCW simultaneously, flags violations as hours are entered, forecasts developing breaches, and exports PSC-ready records — on the same crew list as crewing and payroll. Book a demo.
Request a DemoFrequently Asked Questions
What are the minimum rest hours for seafarers?
10 hours in any 24-hour period and 77 hours in any 7-day period; split into no more than two periods, one at least 6 hours, with no more than 14 hours between consecutive rest periods.
What does "any 24-hour period" mean?
A rolling window. Compliance must hold for every possible 24-hour period, not just midnight to midnight — which is why day-by-day checking misses violations.
How do MLC and STCW differ?
The numbers align, but MLC 2006 applies to all seafarers and allows a State to set maximum work hours (14/24, 72/7 days) instead, while STCW applies rest limits to watchkeeping personnel. Ships are commonly assessed against both.
Can rest be reduced in an emergency?
Yes — the master may suspend the schedule for the immediate safety of the ship, persons or cargo, or to assist others in distress, followed by adequate compensatory rest.
How are records kept?
Daily, endorsed by the master or authorised person and by the seafarer, with a copy provided to the seafarer, retained on board and available for inspection.
Scope & Sources
This guide summarises publicly available material on MLC 2006 Standard A2.3 and STCW rest-hour provisions. The convention texts, your flag Administration's implementing legislation and any applicable collective agreement take precedence. National implementation varies, and requirements evolve — verify before acting. Nothing here constitutes legal advice.