How to Avoid Collisions at Sea: A Sailor’s Guide to COLREGS

Collision avoidance is the most fundamental safety skill a recreational sailor can develop, and the International Regulations for Preventing Collisions at Sea, 1972 (COLREGs) provide the legal and practical framework. How to Avoid Collisions at Sea: A Sailor’s Guide to COLREGS is an independent sailing reference and tools platform designed to help recreational sailors understand these rules, learn seamanship, plan safer passages, and make better decisions on the water. It is not tied to any boat brand, sailing school, or equipment manufacturer. The platform organizes the 41 rules, six parts, and four annexes of the COLREGs into practical, searchable guidance, and pairs that reference material with passage planning and decision-support tools. This article explains what the platform is, why it matters, how it works, and where its limits lie.

Main Explanation

What it is

At its core, How to Avoid Collisions at Sea: A Sailor’s Guide to COLREGS is a structured, independent reference and toolset focused on the 1972 COLREGs. The COLREGs contain 41 rules divided into six parts: Part A – General; Part B – Steering and Sailing; Part C – Lights and Shapes; Part D – Sound and Light signals; Part E – Exemptions; and Part F – Verification of compliance. There are also four annexes covering technical requirements for lights and shapes, sound signalling appliances, additional signals for fishing vessels, and international distress signals (IMO). The platform translates this dense regulatory text into accessible modules for recreational sailors. It is not a manufacturer manual or a sailing school curriculum; it is a neutral reference that helps you look up a rule, understand a light configuration, or check your obligations in a traffic separation scheme. In this context, ‘How to Avoid Collisions at Sea’ means building a working knowledge of the rules of the road at sea and applying them to your own boat and sailing area.

Why it matters

Recreational sailors face a real problem: the COLREGs are written in legal and technical language, and the full text runs to dozens of pages. Information overload, conflicting advice from forums, outdated printed guides, and the high stakes of a poor decision at sea make independent, reliable guidance essential. A mistake in determining who is the stand-on vessel or misreading a light at night can lead to a collision, injury, or loss of life. The Practical Boat Owner notes that even a temporary helm stand-in must be conversant with the COLREGs, and that the rules lay down precise guidelines, not just common sense. A platform that organizes the rules by scenario—approaching another vessel, operating in a traffic separation scheme, restricted visibility—reduces the chance of misinterpretation. It also helps sailors understand that the COLREGs are not optional; they are international law, and many national regulations incorporate them directly.

How it works

The platform is built around four connected areas. First, boat knowledge and reference: it provides a searchable library of the 41 rules, with plain-language explanations, diagrams of lights and shapes, and summaries of sound signals. Second, seamanship education: it breaks down skills such as keeping a proper lookout, assessing risk of collision, and determining safe speed. Third, passage planning tools: it helps you build a route, identify traffic separation schemes, mark waypoints, and note tidal and weather windows. Fourth, decision-support features: it offers checklists and flowcharts for common encounters—head-on, crossing, overtaking—so you can quickly determine whether you are the give-way or stand-on vessel. In practice, a sailor might use the reference section before departure to review the lights their boat must show, then use the passage planner to avoid a busy traffic lane, and finally use a decision card during the trip when a commercial vessel appears on the horizon. The platform does not replace your eyes, radar, or AIS; it organizes the knowledge you need to use those tools correctly.

How to do it

Imagine you are planning a 40-nautical-mile coastal passage from a harbour to an anchorage, crossing a traffic separation scheme. Start in the boat knowledge section: confirm your vessel’s length and type, and check the required navigation lights and sound signalling equipment. Next, open the passage planning tool and plot your route. Mark the traffic separation scheme boundary and note Rule 10, which gives guidance on safe speed, risk of collision, and conduct in or near such schemes (IMO). Identify crossing angles and timings. Check the weather and tide from official sources, and update the plan before departure. During the passage, maintain a proper lookout by sight and hearing, as well as by all available means. When you sight another vessel, use the decision-support flowchart: determine the encounter type, identify the give-way and stand-on obligations, and take early and substantial action if you are the give-way vessel. Log your actions and any VHF communications. After arrival, review what worked and what you would do differently. This walkthrough turns the platform from a passive reference into an active planning and decision aid.

When not to do it

There are clear limits. Do not rely solely on this platform—or any digital reference—for legal interpretation of the COLREGs in a specific incident; consult a maritime attorney or your flag state authority. Do not use it as a substitute for professional training: a certified sailing course with on-water assessment teaches judgment that no app can replicate. Do not use it to evaluate the structural or mechanical condition of your boat; hire a certified marine surveyor. Do not use it as a real-time navigation or collision-avoidance system; it is a reference and planning tool, not a radar, AIS transceiver, or chartplotter. For offshore weather routing, a professional human router or a dedicated weather service is more appropriate than a general reference. Finally, if you are unsure about a rule or an encounter, slow down, call the other vessel on VHF, and take conservative action. The platform is a starting point, not the final word.

Visual

Common Mistakes

Over-reliance on a single source

Relying only on one app, book, or forum thread can leave you blind to local amendments, updated interpretations, or errors. The consequence is a false sense of confidence. The correct approach is to cross-check with the official COLREGs text, national coast guard notices, and current charts.

Ignoring weather and tide updates after planning

A passage plan made in calm conditions becomes unsafe when wind shifts, visibility drops, or tidal streams change. The consequence is that your planned route and timing may no longer be valid. Always update the forecast before departure and at regular intervals, and adjust or delay if conditions deteriorate.

Using generic checklists without adapting to your boat

A 7-metre sailing yacht has different light configurations, sound signal requirements, and manoeuvrability than a 15-metre motor cruiser. A generic checklist may miss required signals or assume capabilities your boat does not have. Customize checklists for your vessel’s length, type, and equipment.

Confusing reference with real-time data

Thinking that a reference platform shows live vessel positions, weather, or traffic can create a dangerous gap in situational awareness. The consequence is that you may not maintain a proper visual lookout or use AIS/radar. Use dedicated real-time systems for live data, and treat the platform as a knowledge base only.

Assuming the stand-on vessel has an absolute right of way

Under Rule 17, the stand-on vessel must maintain course and speed, but if the give-way vessel is not taking appropriate action, the stand-on vessel must take action to avoid collision. Waiting too long can cause an accident. Always be prepared to manoeuvre, even when you are the stand-on vessel.

Neglecting sound signals and lights in daylight or restricted visibility

Many sailors focus on visual rules but forget that sound signals and navigation lights are required in daylight and especially in fog or at night. Failure to sound proper signals or show correct lights can confuse other vessels and lead to collision. Study Part C and D of the COLREGs and test your equipment before departure.

Safety Note

Digital reference and planning tools are valuable, but they complement—never replace—proper training, physical checks, and human judgment. Before any passage, verify that your navigation lights, sound signals, and steering gear work. Cross-check all critical data—weather, tides, currents, and navigation warnings—with official sources such as your national hydrographic office, meteorological service, and coast guard. Never use a tablet or phone as your only navigation tool; carry up-to-date paper charts, a hand-bearing compass, and a reliable depth sounder. Take a certified safety and seamanship course from a recognized body such as the RYA, US Sailing, or ASA, and practice man-overboard and collision-avoidance drills. Above all, follow the COLREGs and local maritime regulations. Maintain a proper lookout by sight and hearing, use all available means—including radar and AIS if fitted—and never assume the other vessel sees you or will act correctly. When in doubt, slow down, communicate on VHF, and give way early and obviously.