There’s no need to be in the dark if your preparation is thorough and easy to understand, says Dick Everitt

The best way to learn to navigate at night is to go to sea on an RYA course, writes Dick Everitt.

They’ll teach you how to cope, without relying solely on a chart plotter, and then you can practise on your own boat. Ideally choose full-moon periods, so you have some light, but remember the tidal streams will be flowing a bit stronger then.

Everything onboard seems harder to do at night, and really basic stuff can mess things up. One very experienced skipper confessed that he couldn’t find a superyacht’s backlight controls, and thousands of pounds worth of nav screens gradually faded away as it got dark.

At the other end of the scale, I found a cheap repeater was far easier to read than the expensive screens feeding it. It’s no good having electronic data that you can’t read, so try kit at night on other boats, or put a black cloth over your head when you try it in the shop.

Always make sure your passage planning notes and regular fixes are backed up on paper.
It’s a debatable point whether or not a red chart table lamp preserves night vision, and I prefer a dimmed white headlamp or a tiny torch that you can mask with your thumb. This can also be used in an emergency to revive the luminous chips in some types of hand bearing compasses.

Binoculars with an internal compass are useful but I find their lights vary a lot: some thin lubber lines are harder to see than chunky arrows. Make sure your crew can actually use binoculars at night – I know of one situation where a female crewmember couldn’t use the internal compass because her small hands couldn’t reach the light button!

List of lights

Offshore, day and night navigation is pretty much the same, but near the coast you need to be aware of all the various lights on buoys, etc. We looked at lighthouses, ranges and timing last month, but you must be clear what all the terms mean. My aide-mémoire for occulting is ‘the occult is a black art’, so it will have a black flash (the light period is longer than the dark), and ‘iso’ means equal, so isophase has equal periods of light and dark.

Make a ‘list of lights’ with all their characteristics noted in a way that you understand. It’s no good the almanac describing a sector light as ‘Oc WR 4s 38m W17M, R13M; 150°-W-115°-R-150°’ if you don’t know what it means.

Mark bearings on the chart where you should see the next light

Mark bearings on the chart where you should see the next light

Plan a simple, well-marked approach, and if you get disorientated don’t press on regardless hoping to find the next light. Stop, and if necessary go back to a known position.
You need to be more methodical at night because there aren’t the visual clues for a quick ‘eyeball navigation’ check. Mind you, lights are often easier to identify than landmarks.

Before GPS it was good practice to close the land just before dawn to pick out shore lights, rather than smudgy coastal features. But even with GPS, some people forget that the tide and wind could be pushing them sideways and just head for the light on the end of the harbour wall, as soon as it appears.

It’s an easy mistake to make when you’re tired and just want to get in. Sadly, some are swept into danger before they know it – so always check cross track error (XTE) right into the harbour waypoint, or approach on a known compass bearing.

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Turning waypoints

Even inside the harbour you still need to navigate, and know where you should look for the next light.

A well-marked channel on the chart can be confusing in reality – especially if it winds a lot, or there are shore lights, or if there are other lit channels in the distance. A chart plotter will keep you orientated, but if you don’t have one you should have turning waypoints, or draw a sketch with bearings for each leg of the channel.

Don’t just head for the next green light, because if it’s damaged you could miss it and end up cutting the corner over the putty (see illustrations below).

The channel should look like this when all the lights are working properly. The light on the far left marks the corner where we have to turn

The channel should look like this when all the lights are working properly. The light on the far left marks the corner where we have to turn

Here’s what it would look like if that light was out for some reason. It would be easy to make an assumption that the next green light is the one we want and go aground. Checking the bearing would avoid this mistake

Here’s what it would look like if that light was out for some reason. It would be easy to make an assumption that the next green light is the one we want and go aground. Checking the bearing would avoid this mistake

If it’s a big harbour, listen to VTS (vessel traffic services) because they should say if any lights aren’t working, and then you can take extra care so you don’t run into a massive unlit navigation mark.

If you can afford all the latest kit – and if it’s accurate – you could just turn on the autopilot linked to the chart plotter and it’ll take you to your destination.

This gives you the opportunity to spend more time looking out for pot buoys or other boats, but it’s nice to be confident enough to know that you could keep going with just a handheld GPS, or failing that a chart and compass.