See unitsPersonal safety, social responsibilities and preventing violence and harassment (STCW A-VI/1-4)
Fatigue, hours of rest, alcohol and drugs
1The lesson in plain words
Fatigue and alcohol impair your judgement. Meet the rest requirements and follow the ship's drug and alcohol rules.
What fatigue does
Fatigue is a state of tiredness that lowers your alertness, slows your reactions and makes you take poor decisions. You may not notice it yourself. Causes include too little or broken sleep, night work against the body clock (the circadian rhythm), noise, vibration, heat, ship motion, long hours, stress and changing schedules such as watch changes and port calls.
Hours of rest
STCW (section A-VIII/1) and the Maritime Labour Convention (regulation 2.3) set minimum hours of rest: at least 10 hours in any 24-hour period and 77 hours in any 7-day period. The rest may be split into no more than two periods, one of them at least 6 hours long, and the gap between rest periods must not exceed 14 hours. Drills should disturb rest as little as possible. In an emergency the master may suspend these rules, and you get compensatory rest afterwards.
Records
Your hours of rest are recorded on board and you receive a copy, signed by you and the master or a person he authorises. Fill them in honestly: false records hide fatigue and break the law. If you cannot get your rest, tell your head of department. Rest is off-duty time, excluding short breaks; it is not the same as sleep.
Alcohol
Alcohol slows reactions and judgement and stays in the blood for hours. Under STCW A-VIII/1, flag states must set a limit of no more than 0.05 % blood alcohol (BAC) or 0.25 mg/l in the breath for anyone on watch or on safety, security or pollution duties. Many companies go further with a zero alcohol policy and random tests. Know your company's rules.
Drugs and medicines
Illegal drugs are banned on every ship, and carrying them can bring prison in many countries. Some legal medicines cause drowsiness. Tell the officer responsible for medical care what you take, and do not stand watch if a medicine makes you sleepy.
2Key data
- Minimum rest
- 10 h in any 24 h and 77 h in any 7 days
- Splitting rest
- At most 2 periods, one at least 6 h
- Gap between rest periods
- No more than 14 h
- Maximum STCW alcohol limit
- 0.05 % BAC or 0.25 mg/l in breath
- Rules
- STCW A-VIII/1 and MLC regulation 2.3
3Key points
- 1
Fatigue lowers alertness and judgement, and you may not notice it yourself.
- 2
Minimum rest: 10 h in any 24 h and 77 h in any 7 days.
- 3
At most two rest periods, one of at least 6 h; no more than 14 h between them.
- 4
Record your rest honestly; tell your head of department if you cannot get it.
- 5
STCW maximum: 0.05 % BAC or 0.25 mg/l breath; flag-state or company limits may be lower.
4Frequent mistakes
Wrong: Ten hours off duty guarantees that I am fit for watch.
Right: Rest is not the same as sleep. If you are still fatigued, tell the officer and ask for relief. Record your actual rest honestly.
Wrong: Writing the standard hours on the rest record keeps everyone out of trouble.
Right: False records hide fatigue and break the law. Record what really happened.
Wrong: One beer before watch is fine if you feel normal.
Right: Alcohol affects you before you feel it, and your company may allow none at all. Follow the policy.
5Practice case & exam keys
Your ship had a long night of cargo work, then sailed at dawn. You slept only four hours, and now you are due on lookout at noon. You feel heavy and keep yawning.
Show the answer
Tell the officer before watch that you are too tired to work safely. Four hours’ sleep can leave you fatigued even if recorded rest meets the rules. Ask for relief and enough sleep. Record actual off-duty rest honestly; do not record only the hours you slept.
Exam keys
- Fatigue causes: lack of sleep, circadian rhythm, noise, vibration, heat, motion, stress, schedule changes.
- Rest: 10 h in any 24 h, 77 h in any 7 days; at most two periods, one ≥ 6 h; gaps ≤ 14 h.
- Rest records are kept and signed; fill them in honestly.
- STCW alcohol maximum: 0.05 % BAC or 0.25 mg/l breath; follow stricter applicable limits. Illegal drugs are banned.
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