Watch systems: sharing the night
1The lesson in plain words
A watch system decides who is on deck, who rests and when. Pick one that fits your crew, keep it from the start and rest the skipper too.
Why a system
On a passage of more than a day, everyone needs regular sleep, and someone must always keep lookout (COLREG Rule 5). A watch system sets fixed times on and off. Start it as soon as you leave, not when people get tired. Write it up where everyone can see it.
Two watches
4 on, 4 off alternates two watches. With four crew, each watch can have two people. Four hours off gives less than four hours asleep once handover, meals and preparation are allowed for. 3 on, 3 off shortens each duty period, which can help in cold or rough weather, but also shortens each rest opportunity.
Single watchkeepers
With three crew, 3 on, 6 off puts one person on deck at a time and gives each six hours off. Use a lone watch only when competence, conditions and workload allow a proper lookout; call support early. The others must be ready to wake and help. Swedish-type systems use longer day watches and shorter night watches; versions vary. With two alternating teams, an odd number of daily duty periods swaps their clock times. For three watchkeepers, check the full rota; an odd number alone does not guarantee rotation.
The skipper
The skipper is needed most when tired is most dangerous: at landfall, in bad weather or in an emergency. Many skippers keep out of the watch system, or take a light share, and sleep when they can. On a short-handed boat, plan for the skipper to sleep too.
Handover
At each change, the outgoing watch tells the next one: course and speed, sails, the position on the chart, ships and lights in sight, weather trend and anything odd. The new watch must be alert, with eyes adjusted and a harness on before taking over. Record the handover in the log.
2Key data
- 4 on, 4 off
- Two alternating watches; sleep time is less than off-watch time
- 3 on, 6 off
- Three single watchkeepers; six hours off each
- Swedish-type
- Longer day watches, shorter night watches; no single standard
- Lookout
- COLREG Rule 5: proper lookout at all times
- Spanish terms
- Guardia, cuarto, relevo de guardia, cuaderno de bitácora
3Key points
- 1
Start the watch system as soon as you leave, before anyone is tired.
- 2
4 on, 4 off for two watches; 3 on, 6 off only if each person can safely keep watch alone.
- 3
With two alternating teams, odd daily duty periods swap clock times; Swedish-type versions vary.
- 4
Keep the skipper rested for landfall and emergencies; hand over properly.
4Frequent mistakes
Wrong: Start watches at dark when people get tired.
Right: Start the system from departure, so that people rest before the first night.
Wrong: The skipper keeps a full watch and also every hard job.
Right: A worn-out skipper is a risk. Leave the skipper some protected rest.
5Practice case & exam keys
Three of you are sailing 220 NM, about 40 hours. The other two want to keep everyone on deck together through the first night 'for safety', then rest on day two. Your landfall is planned at 0500 on the second night. What do you propose?
Show the answer
Everyone on deck all night means everyone tired for landfall. Use 3 on, 6 off only if each person can safely keep the watch alone; otherwise arrange overlapping support and revise the rota. Start from departure. Keep the others ready to wake and help. Protect your rest as skipper before 0500. Agree when to call you and review the rota after the first night.
Exam keys
- Watch systems from departure; proper lookout at all times (Rule 5).
- 4 on, 4 off; 3 on, 3 off; 3 on, 6 off; uneven (Swedish-type) systems.
- Rest the skipper for landfall and emergencies.
- Structured handover recorded in the log.
Finish this unit
When you've read it, match the terms, then answer three questions. Get them all right to finish the unit; opening the page alone doesn't count.
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