Night sailing: vision, lights and the watch that nobody enjoys

Everything is harder after dark, and most of it is avoidable. Night sailing goes wrong through preparation rather than seamanship: a screen that ruins everybody's vision, gear stowed where it cannot be found, and a watch pattern that puts the least confident person alone in the cockpit at 03:00.

Night vision, and how quickly you lose it

Full dark adaptation takes twenty to thirty minutes and a single white light destroys it in a second. That is the whole argument for red instrument lighting, red head torches, and dimming every screen aboard to the point where it looks unusably dark in the cabin — because on deck it will be right.

The chart plotter is usually the worst offender, followed by somebody's phone. If an app cannot go red on black with its own dimmer, it does not belong on deck at night.

Reading other vessels

Practise the basics until they are automatic: two masthead lights in line means you are looking at a vessel over fifty metres and roughly end-on; a red over white is a fishing vessel; three whites in a vertical line means she is towing and the tow may be unlit and half a mile behind.

Trust the lights over the AIS. AIS tells you what is transmitting, not what is there, and the fishing boat that has been on the same bearing for twenty minutes with no signal is the one that matters.

The watch that nobody enjoys

The 00:00 to 04:00 is harder than any other watch, so the one rule that matters is that it must rotate. If the same person has it every night for ten nights, no amount of good gear compensates. See watch systems compared.

Pair the least experienced crew with somebody who has been on deck a while, keep night watches to three or four hours, and wake people on their own lead time so nobody arrives on deck still asleep. Then write down when to call you, so a nervous watch at 03:00 does not have to decide alone — see standing orders.

Small things that make a large difference

A torch in every berth. Lee cloths on the sea berths. Somewhere for wet oilskins. A flask made before dark, because nobody boils a kettle at 02:00 on a rolling boat. Snacks in the cockpit so the watch does not go below and lose their vision. And a clock everybody can read without a screen — the single most looked-at object on a night watch is the time until handover.

Setting the boat up before sunset

The half hour before dark decides how the night goes. Reduce sail to what you would be comfortable with in fifteen knots more than you have, because reefing at 02:00 with two people is a different job from reefing at 18:00 with five. Rig the preventers on both sides while it is still light, whether or not you expect to gybe.

Then deal with the small things that are impossible in the dark: torch in every berth, lee cloths up, wet-weather gear where the on-watch can find it without going through the saloon, flask made, snacks in the cockpit, and the companionway light switched to red.

A handover that actually transfers the picture

The purpose of a handover is not to swap seats. It is to move a mental model of the situation from one head to another — where the traffic is, what the wind has been doing over the last hour rather than this second, what is set, what is broken, and what the skipper has said about calling.

A workable script takes ninety seconds and covers five things in the same order every time, so nothing is forgotten by a tired person: position and course, wind and its trend, traffic and what you have decided about it, what has changed on deck, and anything outstanding. Then the incoming watch says it back.

Squalls, and what to do about them at night

In the trades you will get squalls, usually between midnight and dawn, and mostly they are twenty minutes of thirty knots and rain. What makes them dangerous is that you cannot see them coming without radar, and the crew on watch is the one person aboard least able to judge whether this one is worse than the last.

The practical answer is a standing instruction rather than a judgement: if the wind reaches a stated number, reef before calling; if it reaches a higher number, call regardless. Radar on the four-mile scale picks squall cells up well, and a torch shone at the clouds astern tells you more than you would expect. See the standing orders template for the thresholds.

Being alone on deck

Plenty of experienced crews stand single-handed night watches in open water and always have. The honest position is that it is a calculated risk that depends on three things: whether the person is tethered, whether anybody would notice their absence quickly, and whether they will wake somebody rather than solve a problem alone.

If any of the three is in doubt, pair the watch or stagger it so somebody is always already on deck. A crew of six can run staggered pairs without anybody doing more hours, which is usually a better answer than a rule nobody follows.

Questions skippers ask