who is responsible for avoiding a collision between two boats
Tutorials

Who is responsible for avoiding a collision between two boats

COLREGS Explained

Collision Regulations (COLREGS) Explained

We love to boat, as do many other people around the world. This love for the sea and other waterways inevitably leads to crowded areas where, just like in a car, you need to know the rules of the road.

Savvy Navvy users regularly find themselves sailing or boating in busy waters, shared with everything from highly manoeuvrable small craft to vast unyielding tankers. Avoiding a collision or a near miss is high on our list of safety priorities, which is why we all need to know and abide by the COLREGs.

Where did boat collision regulations come from?

Collision rules for seafarers started to be codified centuries ago and today’s Collision Regulations became law in most countries under the auspices of the IMO in the early seventies. Updated or enlarged a few times since, they now come in six official languages. Many countries publish similar rules for inland waterways, and there are modified COLREGs for yacht and dinghy racing. It is important to understand that COLREGs are the law and not a guideline, and they apply even if a collision has not actually taken place. It is also important to understand that contravention of COLREGs can be a criminal offence in the worst cases. All vessels in an encounter are ultimately obliged to avoid a collision, including the one which is “Stand On”.

Brilliant navigational App clearly designed by people who understand what boaters really need. The passage planning is superb taking account of the predicted wind and tide at your proposed time of departure advising you whether wind and tide are in your favour. One navigational app that does it all.
Ross Lucas-Young - Savvy Navvy Subscriber

Ross Lucas-Young

Try it for free

The rules begin with a simple explanation of who gives way and who stands on when two vessels approach one another, but by the time visibility, propulsion methods, draft, communication, signalling, lights, towing and pushing, fishing boats, anchored vessels etc are covered, it will be no surprise that the bare bones UK version is over 12,500 words. The United States Coastguards version of the rules, which incorporates inland rules and many tables and diagrams, runs to almost 4 times as many words, even though both follow the same structure of 41 rules and 5 annexes.  

None of us took up sailing to memorise thousands of words, but COLREGs are vital and must be understood. The solution is not to view learning COLREGs as a reading or study task, but as something that must be regularly practised and refreshed. It only takes 10 minutes to explain to someone how to jump out of a plane and open a parachute, but no-one would dream of doing it without spending days training and rehearsing on the ground. In the same way learning COLREGs by combining reading with physical practice helps us to absorb information and ensure that when the other vessel approaches, we know what to do.

Two yachts cross - know the rules of the road

The 41 Rules of Collision Regulations

The 41 Rules are divided into five parts.

  • Part A contains the General Rules which state that COLREGs apply to all craft, that additional special rules may apply in ports, harbours or inland or to war craft or fishing fleets.
  • Part B is probably the most frequently used section for Savvy Navvy customers, as it sets out the Steering and Sailing Rules. It begins by dealing with lookout duties, vessel speed and radar use, visibility, narrow channels and traffic separation schemes. It sets out rules for giving way, standing on, overtaking and crossing first for vessels in sight of one another and then for those in a situation of restricted visibility. Rule 12 sets out some extra requirements for sailing vessels, as the direction of the wind relative to each boat must be taken into consideration.
  • Part C on Lights and Shapes is essentially about communication. It sets out a boat’s duties to show lights at night and shapes by day to provide important information to other seafarers, signalling the type of vessel and the type of activity underway. To underline the fact that the rules apply to all vessels regardless of size, Rule 25 even specifies that a rowing boat should have a torch. There are rules for fishing vessels, power driven vessels, tugs and pilot boats and even seaplanes. Annex I contains technical detail for lights and shapes.
  • Part D continues the theme of communication but this time using sound and light signals, and sets out quite detailed instructions on how to signal intended maneuvers, especially when visibility is limited. Annex II deals with signals for fishing vessels in close proximity, Annex II has technical details of sound appliances and Annex IV adds more detail about distress signals.
  • The final Part, E, deals with exceptions to the rules that were granted to certain vessels that pre-dated their introduction. In 2013, 3 new rules were added concerning audit requirements bringing the new total to 41 rules.

There are no roads on the open sea, and as the designers of Savvy Navvy’s routing algorithm are well aware, navigation is much more complex than for vehicles on land. The rules range from general principles such as keeping a lookout, to detailed instructions regarding the priority of vessels - Power / Sail /  Fishing / Draught constrained /  Not under Command / Restricted in Ability to Manoeuvre.

What is the best way to learn the Collision Regulations?

As already noted, reading through the rules themselves is unlikely to be enough. There is a whole industry of training courses and different materials such as videos and flash cards to help you absorb the detail and be ready to turn it into action. COLREGs are also covered in sailing or powerboating qualification courses. Our ambassador Oliver Cotterell from OC Marine always gets his students to learn rules 1-19 first as they are the ones they’re most likely to use on the water.

The key tip however is to practice. Discuss situations with your crew. Look at what others are doing on the water. Refresh your memory from time to time. Don’t be a ten-minute parachutist!


Now that you know the rules of the road, plan your next trip with Savvy Navvy. Do you have issues remembering which side of the boat is port? Which side is Starboard?

Savvy Navvy, the boating app that brings all essential marine information together in one place. Featuring global charts, wind and weather forecasts, tidal graphs, GPS Tracking, automatic weather routing, and marina and anchorage information. It’s like Google Maps for boats.

Inspired to get on the water? Start your free trial today.