COLREGS, Lights & Sailing at Night

Despite learning all my lights and being a nerd with the Coastguard Boating Education flash cards, when you are at sea at night it is really hard to decipher navigation lights on other boats.

I think the main difficulty I have is knowing how close you are to the other boat. We don’t have radar on board, so only have our eyes to judge. Is it a huge ship far away or is it a small ship really close? Who knows! Either way, I have no idea how close we got to the fishing boat we passed on the way back from the Sounds in January.

Here is everything I need to refresh for the Ocean Yachtmaster course I am currently doing:

COLREGS – are the international collision regulations at sea.

Firstly you need to turn on your lights from sunset to sunrise and in rain and fog.

Let’s start with the easy ones!

At Anchor

If you are at anchor – you must show an all round white light. If the vessel is over 50m, then they show two all round white lights – one at the front and one at the stern. If the vessel is over 100m in length then they must also show other lights to illuminate the decks.

People who are under way tend to give way to boats which are anchored. (see this is all common sense people!!)

Boats less than 7m and not going faster than 7 kts

They also only need to show an all round white light, or if you are in a dinghy you can use a torch. Basically just try not to run these slow little guys over, and likewise, if you are small and slow you might not want to be navigating through busy shipping lanes at night if people are unlikely to be able to see you. (just sayin’!!)

Port, Starboard & Stern Lights

These are shown when a vessel is under way (i.e. not at anchor) and help you to identify which direction a vessel is travelling. If you can see both the red and green at the same time, then it means they are heading straight for you!

If you can only see a white light then it could either be a vessel at anchor, a slow vessel travelling at less than 7kts or a vessel travelling away from you – its stern light.


Yachts or if you are from America – Sailing Boats

Yachts under 20m, when sailing must show a port, starboard and stern light and they can be combined in a tri-coloured mast head light.

If the yacht is motoring then it also needs to show a seperate stern light and a masthead white light.

Power Boats

Powerboats over 12 metres in length must show the port and starboard lights, a stern light and a mast head light – which should be 1 metre higher than the sidelights.

If the powerboat is less than 12 metres then it can combine its stern and masthead light in to one all round white light.

Towing Light

If you are towing another vessel, you display a yellow light instead of a stern light.

Under Way & Making Way

Under way, means that a vessel is not anchored, docked or secured. Making way means that it is actually moving through the water/over the ground.

Now this is where it gets a bit more complicated…!


Vessels Over 50m in length

Must show two white mast head lights (facing forward) and one white stern light. The front light should be lower than the main masthead light. They also show port & starboard lights.

Vessels Not Under Command

These are vessels which are unable to manoeuvre and keep out of the way of anyone else. Perhaps they have lost all power to their engines or something like that.

They show two in line all round red lights or two red balls during the day. If they are actually making way through the water then they must show port, starboard and stern lights too.

I remember this by thinking of two red stop lights – i.e “Stop stop these guys are not under command”

Vessels Aground

Obviously if a vessel is aground then it isn’t going to be able to give way to anyone else! These guys show two all round red lights over one white.

Vessels Restricted in their Ability to Manoeuvre

These vessels are restricted in their ability to move because of the nature of the work they are undertaking – so they might be dredging, towing, launching aircraft or something like that.

They show three lights all in line red, white red or a ball, diamond, ball during the day.

If they are fishing or dredging, and this might be a hazard to other ships, then they will display two green lights or two diamonds on the safe side, and two red lights or two red balls on the side with the obstruction.

Basically everyone except vessels not under command or aground, must give way.

Not sure how I remember this one but I seem to be able to!

Vessels Constrained by their Draught

These are big ships who are restricted to the channel, and can not deviate or they will run aground. They give way to vessels not under command and vessels restricted in their ability to maneuver, but everyone else gives way to them.

They show three all round red lights in a line or a cylinder during the day.

Pilot Vessel

Shows a white over red light.

I remember this one with the rhyme “White over red, the pilot is out of bed”

Vessel Fishing

A vessel fishing usually shows a red over white light or two triangles facing point to point (wine glass shape)

I remember this one with the rhyme “Red over white, fishing at night”

However they can also show a green over white light if they are trawling. If they have a single triangle out to one side, or a single all round white light, then this indicates that there is fishing gear extending out that side for 150m.

Vessels Towing

If the length of tow is less than 200m the towing vessel shows two all round white lights or a diamond shape and a yellow stern light. The vessel being towed shows their normal lights.

If the length of tow exceeds 200m, then they display three all round white lights.

Other Rules of the Road

In Harbours

Smaller boats should give way to any ships over 50m in length.

In Narrow Channels or meeting head on.

Vessels should stick to the starboard side of the channel, alter course to starboard and pass port to port.

When Overtaking

The overtaking vessel gives way to the stand on vessel being overtaken. The stand on vessel can pass either side, but should make their intentions clear. The stand on vessel should maintain their course, and avoid speeding up to race the passing vessel or swerving over in front of them to stop them from being able to overtake… 😉

Sailing Vessels

Power boats should give way to yachts.

We have got heaps of crazy yacht rules, but basically those on port tack, give way to those on starboard, and windward boat gives way to the leward boat. Alternatively in a race whoever yells the loudest and has the biggest balls usually gets their own way.

Power Vessels Crossing

You must give way to a vessel on your starboard/right hand side. If the vessel to your left does not appear to be giving way to you, then you should turn to starboard, because if you turn to port (or towards them) and they finally figure out what they are doing and try to pass astern, then you could crash.

Honestly, you would not believe the number of people who have boats and have absolutely NO IDEA what any of these rules are. Arraggh!

11 thoughts on “COLREGS, Lights & Sailing at Night

  1. Very cool post, thank you for sharing. It is fun comparing these regs to the regs here in the US. For the most part they are the same however here each State has slightly different rules regarding small boats.


  2. Pingback: Ocean Yachtmaster | Astrolabe Sailing

  3. Pingback: Sailing at Night | Astrolabe Sailing

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