Skipper’s Tips #5 – IALA Buoyage System

Navigational ‘road signs’ at sea would be really useful but I just can’t see it happening, can you?

I guess, on the one hand it would be nice to pop out of the Solent past the Needles and see an arrow pointing straight ahead saying something like “Cherbourg 60 miles” and then ten miles further on, another sign saying, “Cherbourg 50 miles, left a bit please”.

Then again, there are already too many signs on our roadways, do we really want our seas be-speckled with bits of rusty metal, telling us which way to go, when we’re quite capable of reading our charts and referring to our GPS?

Absolutely not!

However, we do need a helping hand when it comes to the shallow bits and it would be nice to avoid bumping into each other when it gets a bit narrow.  Also, GPS might be good but with an accuracy of 60 m most of the time and only 3 m the rest of the time, it would be really nice to know exactly where that wreck actually is.  This, of course, is where the buoyage system comes in.

Once you’ve mastered the rules of how the system works, you’ll find that this will free you up to go further afield.  But don’t fall into the trap of assuming that you need to stick rigidly to the marked channels.  Check your charts carefully, and you will often find that as a small vessel it is quite possible to go ‘the wrong side’ of some of these buoys.  By not using your charts in conjunction with the buoyage system, you will severely reduce the available boating opportunities open to you.

The IALA Buoyage System

The IALA (International Association of Lighthouse Authorities) buoyage system is a global aid for navigating around the seas. It provides guidance for entry and exit from ports and harbours whilst helping us to avoid hidden and sometimes not so hidden dangers.

The buoys/markers have been designed so that they can be recognised at any time of day or night and in all but the worst visibility.  Each buoy will have a specific shape, top mark, colour, light sequence and occasionally will even send a boosted radar signal back to you with a morse-code identity.

The markers that most people recognise are called ‘Cardinal Marks’. This is because they are placed at the cardinal points of a compass i.e. north, south, east and west around a hazard or danger area. Cardinal Markers mark the extremities of the danger area. Therefore, if you see an east cardinal marker, you must stay to the east of it and so on.

Top marks:

· The North cardinal has two triangles pointing upwards (North)

· The South cardinal has two triangles pointing downwards (South)

· The East cardinal has two triangles pointing apart (Egg-shaped)

· The West cardinal has two triangles pointing together (Wine-glass shaped)


The cardinal markers are yellow and black – you could say that the position of the black stripe coincides with the position of the point of the triangle on the top mark i.e. the east cardinal would be painted black, yellow, and black. The south cardinal would be, from top to bottom, yellow and black.

Light sequences:

· The North cardinal – quick or very quick white light, continuously flashing

· The East cardinal – quick or very quick white light, three flashes

· The South cardinal – quick or very quick white light, six flashes plus one long flash

· The West cardinal – quick or very quick white light, nine flashes

Clearly, there are many more buoys/markers in the IALA system.  Everyone should have a copy of the IRPCS (International Regulations for the Prevention of Collisons at Sea) on board and this is where you’ll find all the other bouys/markers in the system.

This has been another Captain Corbett’s Adventure.  If I’m not on Jersey teaching a private tuition Day Skipper theory or Yachtmaster theory course, then I’m either spending time with someone on their boat, giving them the confidence to take their boat out with their family and friends on board or I’m off somewhere exotic delivering a boat. Either way, I’ll write it up and put it on the Blog for you all to see, so keep popping back to see my most recent adventures.

2 thoughts on “Skipper’s Tips #5 – IALA Buoyage System

  1. Hello Captn…as you say, long time no hear etc etc must say on your bouyage “skippers tips” never gave the “points toward black” a thought !!!. nice 1 skip !!


    1. Thanks Steve. It’s all really logical when you think about it – sometimes you just need someone like me to confirm what you’ve already worked out for yourself!

      Are you off on any adventures at Easter?


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