The total rest period for a seafarer/fisherman in a week must be at least 77 hours. All rest periods count towards this total. A week is a continuous 7-day period.
The ship's Master or fishing vessel skipper may require a seafarer or fisherman to work when necessary, such as for the safety of the ship. If a seafarer or fisherman is required to perform such work during a scheduled rest period, they are entitled to a sufficient rest period as soon as possible.
Seafarers and fishermen younger than 18 years of age
If you are under 18 years old, you must have a total rest period of at least 12 hours within any 24-hour period. The rest period for seafarers under 18 years old should generally be between 8 PM and 6 AM. However, if you are on duty, the rest period can be divided into a maximum of two periods, with one period lasting at least 8 hours between 8 PM and 6 AM. Within each 7-day period, seafarers under 18 years old must have two consecutive days off, which can be postponed for later compensatory rest."
More on hours of rest
Recording periods of work and hours of rest
Deviations from hours of rest by agreement, including registration of such an agreement