Learn the COLREGs
The Rules of the Road, taught rule by rule, with narrated lessons, scenarios and quizzes.
View COLREGsMarks, lights and shapes
Buoyage, lights and shapes
The IALA buoyage system, and the navigation lights and day shapes that identify a vessel.
This course joins two subjects that sit next to each other on the water. Buoyage is how a channel, a danger or safe water is marked. Lights and day shapes are how another vessel tells you what it is and what it cannot do.
The buoyage half is the IALA Maritime Buoyage System. You learn lateral marks in both IALA Region A and Region B, then cardinal marks, isolated danger marks, safe water marks and special marks. Light characters are taught with the marks, and the last buoyage modules put those marks onto the chart.
The lights and shapes half is recognition training from Rules 20 to 31 of the COLREGs. You drill masthead lights, sidelights, stern lights, towing and fishing lights, and the shapes for a vessel not under command, restricted in her ability to manoeuvre, constrained by draught, at anchor or aground. Learn the COLREGs already teaches those rules inside the full collision regulations course. This half stays on identification.
What you will learn
- Name the five types of mark in the IALA system and the job of each
- Leave lateral marks on the correct side in IALA Region A and Region B
- Read a cardinal mark and pass it on the safe side, by day and by night
- Recognise isolated danger, safe water and special marks, and match a light character to its mark
- Name the arcs and colours of masthead lights, sidelights, stern lights and all-round lights
- Identify power-driven, sailing, towing, fishing, pilot, anchored and aground vessels
- Identify vessels not under command, restricted in ability to manoeuvre, and constrained by draught
- Match day shapes to the lights that carry the same meaning
Who this course is for
Yacht crew learning the marks and the lights
One course for Region A, which covers the UK and most of the world, Region B, which covers the Americas, Japan, Korea and the Philippines, and the vessel lights and day shapes you meet in harbour.
Watchkeepers changing waters
A precise refresher when you move between IALA regions, or when you want light characters and vessel lights sharp again before a night watch.
COLREGs students who want more drill
Use this beside Learn the COLREGs if Blocks 4 and 5 showed you the rules and you now want repetition, together with the buoyage the rules do not teach.
Course format
Self-paced online. Plan for about 10–14 hours. Lessons run in a browser on a laptop, tablet or phone. There is nothing to install. When you finish, Sea Skills Online issues a certificate of completion. That certificate records your study. It is not an STCW, MCA or RYA certificate.
Watchkeepers, yacht crew and new navigators. Price £39. Checkout creates your account, or signs you in, takes payment through Stripe, and adds the course to your dashboard.
Tutor support
Unlimited free tutor support is included. If a lesson does not make sense, email hello@seaskillsonline.com. There is no extra charge, and there is no limit on how often you write.
Course contents
How the IALA system is organised
Conventional direction of buoyage, the two regions, and what colour, shape, topmark and light each tell you.
Lateral marks in Region A
Port-hand and starboard-hand marks, preferred-channel marks, and which side to leave them when entering a harbour.
Lateral marks in Region B
The reversed lateral colours of IALA Region B, and how to avoid carrying Region A habits into American and East Asian waters.
Cardinal marks
North, east, south and west cardinal marks by topmark and by light, and where the safe water lies.
Isolated danger, safe water and special marks
The marks that are not lateral or cardinal: what they protect, what they promise, and what they deliberately do not tell you.
Lights and rhythm on the marks
Flashing, quick, group-flashing and occulting characters used by the buoyage system, practised against the mark they belong to.
Marks and the chart
Chart symbols for buoys and beacons, light descriptions, and using a mark as a waypoint or a clearing feature.
Buoyage identification practice
Mixed day and night recognition across both regions, in the order a real approach puts the marks in front of you.
Why lights and shapes exist
When lights are shown, when shapes are shown, and what you are entitled to assume from them.
Definitions and range
Masthead light, sidelights, stern light, towing light, all-round light, flashing light, and how far each must be seen.
Power-driven vessels under way
Vessels under 50 metres and 50 metres or more, vessels under 7 metres, and air-cushion vessels.
Towing and pushing
Tows astern, tows alongside, composite units, and the diamond that tells you the tow is long.
Sailing vessels and vessels under oars
Sidelights and stern light, the optional tricolour and the all-round red-over-green, and a torch for a small boat.
Fishing vessels
Trawling and fishing other than trawling, by night and by the day shape of two cones.
Not under command, restricted, and constrained by draught
Red over red, red-white-red, the three reds of a vessel constrained by draught, and the shapes that match them.
Pilot vessels, anchored and aground
White over red for a pilot, the anchor light and ball, and the extra reds and balls of a vessel aground.
Identification drills
Mixed sets of vessel lights and day shapes, from a straightforward power-driven vessel to the tow you meet in a channel.
Buoyage follows the IALA Maritime Buoyage System. Lights and shapes follow Rules 20 to 31 of the collision regulations.
Related maritime courses
Common questions
Is buoyage, lights and shapes one course?
Yes. IALA buoyage and navigation lights and day shapes are taught together and sold as one course. You do not buy them separately.
What is the difference between IALA Region A and Region B?
In Region A, which includes Europe, Africa, most of Asia and Australia, you leave red lateral marks to port when entering a harbour. In Region B, which includes the Americas, Japan, Korea and the Philippines, you leave red lateral marks to starboard. Cardinal, isolated danger, safe water and special marks are the same in both regions.
Is this the same as the lights section of the COLREGs course?
The lights half teaches Rules 20 to 31, with more time on recognition. Learn the COLREGs already includes lights and shapes as two blocks inside the full collision regulations course. This course adds the IALA buoyage system, which the COLREGs course does not teach.
Are day shapes included?
Yes. Every lights module that has a day shape teaches the shape next to the lights, including balls, cones, diamonds, cylinders and the shapes for fishing, towing and vessels aground.