Seafarer rest hour limits per 24-hour and 7-day window and how violations are judged

The numbers in the rest hour rules are easy to remember. Ten hours in 24, and 77 hours in seven days. But if you compute them as calendar-day totals, you get a different answer from the one the rules ask for. What the text fixes is not a total per date. It is a window that must hold wherever you cut it.

This article puts the wording of MLC, 2006 Standard A2.3 and STCW Code Section A-VIII/1 side by side and sets out what the two instruments actually require.

The 24 hours and 7 days are windows you can cut anywhere, not calendar days

MLC Standard A2.3, paragraph 5 uses the words in any 24-hour period and in any seven-day period.

5. The limits on hours of work or rest shall be as follows: (a) maximum hours of work shall not exceed: (i) 14 hours in any 24-hour period; and (ii) 72 hours in any seven-day period; or (b) minimum hours of rest shall not be less than: (i) ten hours in any 24-hour period; and (ii) 77 hours in any seven-day period.

any means any. Not the day that runs from 00:00 to 24:00, but a period that holds wherever its start is placed. So a schedule whose per-date totals both clear ten hours can still fall short of ten hours in a 24-hour window that straddles the two dates.

Take an example. A seafarer rests from 20:00 on the first day to 04:00 on the second, eight hours, and rests two more hours during the first afternoon. The calendar-day total is ten hours. If the second day is arranged the same way, its total is also ten hours. Now cut a window from 12:00 on the first day to 12:00 on the second: the rest inside it can be eight hours. Calendar-day arithmetic never forms that window, so it passes, and the rule treats it as a violation.

To judge this correctly you have to slide the window and find the minimum. The rest total is piecewise linear in the window start and the slope only changes where work turns into rest or back, so scanning every one of those transitions gives the true minimum. Scanning at one-hour steps misses the worst window when it sits on a half hour.

The work-hour ceiling and the rest-hour floor differ by 19 hours a week

Paragraph 5 above puts or between (a) and (b). A flag State fixes either maximum hours of work or minimum hours of rest. Not both.

The two are not the same rule written twice. Seven days is 168 hours. Under the rest floor, leaving 77 hours of rest allows at most 91 hours of work. Under the work ceiling the limit is 72 hours. Which regime applies to a ship moves its weekly ceiling by 19 hours.

Strictly, even 91 hours is not the limit. Paragraph 1(b) of A2.3 defines hours of rest as time outside hours of work and adds this term does not include short breaks. A short break is neither work nor rest, so 168 minus 77 hours of rest does not all become time available for work.

This is why you have to know which regime a ship’s flag State chose before you check the records. The table posted on board carries that value too (A2.3, paragraph 10(b)).

The total can be right and the split and the interval still fail

Even with ten hours secured in 24, how those ten hours were divided is a separate requirement.

6. Hours of rest may be divided into no more than two periods, one of which shall be at least six hours in length, and the interval between consecutive periods of rest shall not exceed 14 hours.

Three conditions bind at once. Rest may be split into no more than two periods, one of them must be at least six hours, and the interval between two consecutive rest periods cannot exceed 14 hours. STCW Code Section A-VIII/1, paragraph 3 is the same sentence.

The third condition binds independently of the total. However much rest is secured, work that runs 14 hours without a break is a violation on its own. A four-on, eight-off watch never reaches that condition, but a day where the watch pattern collapsed for arrival, departure or cargo work does.

So a violation is not one thing but five.

Violation	Provision	Value it is judged on
Under ten hours	A2.3 paragraph 5, A-VIII/1 paragraph 2	Minimum rest in any 24-hour window
Under 77 hours	A2.3 paragraph 5, A-VIII/1 paragraph 2	Minimum rest in any 7-day window
More than two periods	A2.3 paragraph 6, A-VIII/1 paragraph 3	Number of rest periods that day
No six-hour period	A2.3 paragraph 6, A-VIII/1 paragraph 3	Longest single rest period
Interval over 14 hours	A2.3 paragraph 6, A-VIII/1 paragraph 3	Longest work run between rests

Each is fixed a different way, so writing “non-compliant that day” in one line leaves you without the thing to change next.

STCW and MLC do not apply to the same people

The identical numbers make it easy to treat these as one rule, but their scope differs.

STCW Code Section A-VIII/1, paragraph 2 states who is covered.

2 All persons who are assigned duty as officer in charge of a watch or as a rating forming part of a watch and those whose duties involve designated safety, prevention of pollution and security duties shall be provided with a rest period of not less than:

Officers in charge of a watch, ratings forming part of a watch, and those with designated safety, pollution prevention and security duties. MLC Standard A2.3 covers seafarers as a whole. A cook or a purser who stands no watch is under the same limits on the MLC side.

That is why a watch schedule alone cannot demonstrate rest hour compliance. The records of positions that stand no watch have to be there as well.

When exceptions open, STCW gives numbers and MLC gives a procedure

Both instruments allow exceptions, by different means.

STCW Code Section A-VIII/1, paragraph 9 pins the limit of an exception to a number.

9 Parties may allow exceptions from the required hours of rest in paragraphs 2.2 and 3 above provided that the rest period is not less than 70 hours in any 7-day period.

The same paragraph then sets four conditions. An exception from the weekly rest period may not run for more than two consecutive weeks, and the interval between two periods of exception must be at least twice the duration of the exception. Under an exception to the ten hours, rest may be divided into three periods, one of at least six hours and neither of the other two under one hour, while the 14-hour interval stands. And exceptions shall not extend beyond two 24-hour periods in any 7-day period.

MLC Standard A2.3, paragraph 13 sets a procedure instead of a number. Exceptions open only through national laws or regulations, or through a collective agreement authorized or registered by the competent authority. A company and a seafarer cannot open one between themselves.

So a record that applies an exception needs two grounds: which exception provision it is, and what the flag State’s basis for allowing it is.

Drills and call-outs have to give back the rest they took

Musters and fire-fighting and lifeboat drills are to be conducted in a way that minimizes the disturbance of rest periods (A2.3, paragraph 7; A-VIII/1, paragraph 4). That a drill is itself a regulatory duty does not waive the rest hour requirement.

Where a seafarer is on call, such as when a machinery space is unattended, one more condition applies. If a call-out disturbs the normal period of rest, an adequate compensatory rest period is due (A2.3, paragraph 8; A-VIII/1, paragraph 6). A record that notes the call-out but not the compensatory rest does not evidence the requirement.

The master’s authority has the same shape. For the immediate safety of the ship, persons on board or cargo, the master may suspend the schedule and require the hours of work needed (A2.3, paragraph 14; A-VIII/1, paragraph 8). The same provision then requires that, as soon as practicable after the normal situation is restored, an adequate period of rest is provided. The authority does not remove the record. It adds one more thing to do afterwards.

The record needs two signatures, the master’s and the seafarer’s

The record requirement covers format, language, the copy and the signatures.

12. Each Member shall require that records of seafarers’ daily hours of work or of their daily hours of rest be maintained to allow monitoring of compliance with paragraphs 5 to 11 inclusive of this Standard.

The same paragraph continues. Records are kept in a standardized format established by the competent authority, in the working language or languages of the ship and in English. Seafarers receive a copy of the records pertaining to them, and those records are endorsed by the master, or a person authorized by the master, and by the seafarers. STCW Code Section A-VIII/1, paragraph 7 requires the same standardized format, copy and two endorsements, without naming who establishes the format.

The two signatures matter. A record without the seafarer’s endorsement does not meet the requirement even if the format is right. And whether the copy was handed over does not show up in the record itself, so that has to be handled as a procedure.

Posting is a separate duty. The table of shipboard working arrangements is posted in an easily accessible place, and for every position it states the schedule of service at sea and in port and the applicable maximum hours of work or minimum hours of rest (A2.3, paragraph 10). That table is also in a standardized format, in the working language or languages of the ship and in English (paragraph 11).

What to check

• Whether the ship’s flag State chose the work-hour ceiling or the rest-hour floor
• Whether judgement is made on calendar-day totals or by sliding the window
• Whether violations are recorded as one thing or as the five separate types
• Whether records that apply an exception carry the flag State’s basis
• Whether the seafarer’s signature is on the record

The wording of these provisions can differ between editions. The quotations above are from MLC, 2006 as amended, including the 2022 amendments, and from the Manila Amendments to the STCW Code (STCW/CONF.2/34). Where a flag State has set a stricter standard, that standard comes first.