Understanding COLREGS

Understanding COLREGS - Do you know what to do?

Do you know what to do?

Understanding COLREGS

Picture the scenario.

You are driving one of the hundreds of RIBS or motor cruisers whizzing around the Solent in Cowes Week. You see the ferries regularly heading to and from the Isle of Wight from the mainland. But do you ever give much thought to who is required to give way to whom?

If you ended up getting into a situation where suddenly you are in danger of colliding with a ferry or another motor boat doing exactly what you are doing, whose responsibility is it to get out of the way? Who would be culpable if a collision, or even a near miss, occurred?

The International Regulations for Preventing Collisions at Sea, more commonly known as the COLREGS, are quite simply, the Highway Code of the sea. The rules were introduced to make it clear when you are the stand on vessel, when you are the give way vessel and what the correct action to take is when in close quarters with other vessels to avoid a collision.

One of the biggest misconceptions about the COLREGS is they are a guidance document, something to help skippers understand who has ‘right of way’ in potential collision situations. Wrong! They are the law and you have to comply with the lot.

No boat has absolute ‘right of way’ under the COLREGS - even the stand on boat is obliged to take avoiding action in some circumstances. The COLREGS determine who should do what at what point to prevent a collision from occurring.

Failure to comply with the COLREGS – and by that it means a collision doesn’t even need to have occurred, simply that the regulations have been breached – is a criminal offence with a maximum penalty of two years in prison and/or an unlimited fine determined by a Law Court, depending on the severity of the incident.

Rule one of the COLREGS states, ‘These rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.’

In a nutshell anybody using any sort of watercraft as a means of transport – whether motor or sail – should make themselves familiar with the COLREGS. Pleading ignorance in any prosecution case is not going to wash.

Understanding COLREGS

As Gus Lewis, RYA Head of Legal and Government Affairs, explains: “There are 38 separate Rules within the COLREGS and, although some of them are clearly aimed primarily at large commercial vessels, in principle they apply to all vessels. For any set of rules to be effective in avoiding collisions, all vessels need to be following the same rules.

“If we use the Cowes Week example, in open water a ferry might be the give way vessel when crossing the path of a small powerboat but in this situation it is equally incumbent on the powerboat to keep her course and speed to help the ferry take avoiding action.

“The relationship between a small powerboat and a ferry changes when the ferry enters a narrow channel or fairway. All vessels of less than 20m are required not to impede the passage of a vessel that can only safely navigate within a narrow channel or fairway.

“In either situation, however, if it becomes apparent to the stand on vessel that a collision cannot be avoided by the actions of the give way vessel alone then the stand on vessel is itself obliged to take avoiding action.

“As a consequence, if a collision takes place then it is often the case that both vessels are found to be at fault to a certain extent.”

The current edition of the COLREGS was adopted in 1972 but the Rules have been amended several times since. The Rules are divided into five parts A-E covering General Rules (A), Steering and Sailing (B), Lights and Shapes (C), Sound and Light (D) and Exemptions (E).

Although clearly all the COLREGS are important, the steering and sailing rules set out in Part B (Rules 4-19) are the ones likely to be most relevant to small powerboats operating in daylight, with good weather and good visibility.

Rules 4-19 cover the following:

  • Look out
  • Safe speed
  • Risk of collision
  • Action to avoid a collision
  • Narrow channels
  • Traffic separation schemes
  • Overtaking
  • Head on situations
  • Crossing situations
  • Action by give way vessel
  • Action by stand on vessel
  • Responsibilities between vessels
  • Conduct of vessels in restricted visibility

Some of these are general good behaviour rules while others are very specific, prescribed obligations. For example, Rule 9 determines, amongst other things, that a small vessel must not impede a vessel that is so big it can only navigate safely in a narrow channel or fairway.

So how do you go about getting to grips with all these rules of the road? The RYA powerboat scheme covers the COLREGS at an appropriate level during each of the practical courses, with the emphasis being on the practical application of the regulations.

If you are looking for shore-based instruction to learn them then the Essential Navigation and Seamanship course is a great supporting course for those new to powerboating, or as a refresher course, and is available in a classroom or online. The RYA Day Skipper Theory course provides the first comprehensive introduction to COLREGS, which are then revisited in the Coastal Skipper and Yachtmaster Offshore theory.

Meanwhile, if you do find yourself of need of legal advice relating to the COLREGS, the RYA Legal team can assist all RYA members with free guidance on the interpretation and scope and application of the rules.

Visit the Courses and Training section of the RYA website to find which course would best suit your needs and experience, or find a powerboat training centre near you at www.rya.org.uk/wheresmynearest

Top tips for learning the COLREGS:
  • Do a little bit often - flip cards are great as they are visual and can be picked at random
  • Remember the priority between vessels: Power > Sail > Fishing > Constrained by Draught > Not under Command and Restricted in Ability to Manoeuvre
  • Collisions tend not to occur when everybody sticks to the rules
  • When travelling at speed the closing time from seeing another vessel and the potential risk of collision is quite short – knowing the rules without thinking about them crucial.

    For example, two boats travelling at 10 knots close at one mile every three minutes. The distance to the horizon for most small powerboats will be a little over two miles away, that’s only six minutes from seeing to hitting them!
  • Lights and sound signals mostly have a logical build-up / progression. Learning the build makes it easier to decipher the over picture of what you are seeing.


1) Who gives way in each of these diagrams?

2) What type of vessel is indicated by each set of lights? What aspect is shown?


1a) A gives way,

1b) A gives way,

2a) Power vessel probably >50m Length, underway starboard aspect

2b) Power vessel under 50metres underway head on

2c) Sailing vessel underway starboard aspect