COLREGS Rules of the Road for Sailors - Right of Way Guide

Prerequisites

The RYA Competent Crew course has no formal entry requirements and is open to complete beginners. Before this lesson you should have completed:

• Points of sail and basic helming: you need to know what port tack and starboard tack mean, which side is windward and which is leeward, and how to steer a compass course.
• Navigation basics: you need to be able to take a compass bearing with a hand-bearing compass, because that is how you tell whether there is a risk of collision.
• Communication: you should know that VHF can be used to contact another vessel, and the basics of sound signals.
• Weather awareness: you should know the visibility terms, and that fog is visibility of less than 1,000 metres.

The full COLREGs are taught in depth on the RYA Day Skipper course. At Competent Crew level the syllabus asks you to keep a good lookout, to recognise the common lights, shapes and sound signals, and to understand the basic steering rules well enough to report traffic accurately and helm correctly under the skipper's direction.

Learning Objectives

By the end of this lesson you should be able to:

• Explain what the COLREGs are and why every vessel, including a small yacht, must follow them.
• Keep a proper lookout and use a compass bearing to check whether there is a risk of collision.
• Explain the difference between a give-way vessel and a stand-on vessel.
• Apply the basic steering rules: two sailing vessels meeting (port and starboard tack, windward and leeward), overtaking, head-on, crossing, and power versus sail.
• Recognise the navigation lights of a sailing vessel, a power-driven vessel and a vessel at anchor.
• Recognise the day shapes for a vessel at anchor, a sailing vessel using her engine, and the main special vessels (not under command, restricted in ability to manoeuvre, constrained by draught, fishing).
• Recognise the common sound signals, including manoeuvring signals, the doubt signal and fog signals.
• Explain what Rule 8 requires of any action to avoid collision, and why a change of course must be large enough to be seen.
• Describe what a small yacht should do in narrow channels and traffic separation schemes (Rules 9 and 10) and in restricted visibility (Rule 19).
• Work out what a vessel is, and which way she is heading, from the combination of lights you can see, and state roughly how far away each type of light can be seen (Rule 22).

RYA syllabus mapping (Competent Crew practical syllabus, Navigation and Safety items): this lesson covers recognising the lights, shapes and sound signals of the vessels you are most likely to meet, keeping a proper lookout (Rule 5), understanding risk of collision and the basic steering rules (Rules 7, 12 to 17), and knowing what to report to the skipper. The syllabus asks for recognition and sensible reporting; detailed rule citation and scenario analysis are Day Skipper material.

What Are the COLREGs?

The International Regulations for Preventing Collisions at Sea 1972, called the COLREGs or "the Rules of the Road", are the traffic rules of the sea. They apply to every vessel on the high seas and all waters connected to them, from a kayak to a supertanker. In UK waters they are part of the law through the Merchant Shipping Regulations. Breaking them can lead to prosecution, and in any collision, the courts look at how each vessel followed them.

The COLREGs have 38 rules in five parts (A to E), plus four annexes (technical details of lights and shapes, sound signal appliances, signals for fishing vessels fishing in close proximity, and distress signals). The parts that matter most to crew are:

Two definitions are important:

• A sailing vessel is any vessel under sail with no engine running. If the engine is running and driving the boat, even with sails up, the yacht is a power-driven vessel in law.
• Underway means not at anchor, not made fast to the shore, and not aground. A drifting boat is underway.

Rule 2: Responsibility

Rule 2 says that nothing in the rules excuses anyone from the consequences of neglecting "the ordinary practice of seamen". In plain English: being "in the right" is no defence if you could have avoided a collision. A 10 m yacht that holds her course into the side of a 300 m container ship because "sail has right of way" is still at fault, and her crew may still be dead. There is no such thing as "right of way" in the COLREGs, only a duty to keep clear or a duty to stand on, and both vessels must always act to avoid a collision.

Lookout and Risk of Collision

Rule 5: Keep a Proper Lookout

Every vessel must keep a proper lookout at all times, by sight and hearing and by every other means available (radar, AIS). Most collisions happen because nobody was looking. This is the crew's most important COLREGs job.

How to keep a good lookout on a yacht:

• Look all round, 360 degrees, at least every few minutes, including behind you. A systematic scan, bow to beam to stern on each side, works better than a vague look around.
• Use binoculars to identify a vessel's type and heading, and the compass or radar to measure how it moves, but keep looking with your eyes too: binoculars narrow the view.
• Use all means: a radar and AIS do not replace sight and hearing, and many small craft and fishing boats do not show on either. Listen as well: a fog signal, an engine or a horn can warn you of what you cannot see.
• Fast ferries and ships overtaking from astern are often missed, so look behind you regularly.
• Look under the genoa. The big headsail hides the whole sector to leeward and ahead. Crouch down or ask the helm to bear away briefly to check.
• At night, protect your night vision. It takes 20 to 30 minutes for your eyes to adapt fully to darkness, and one look at a white torch or phone screen ruins it. Use red lights below decks.
• Report what you see clearly: what it is, where it is and what it is doing. For example: "Ship, 30 degrees on the port bow, about 2 miles, crossing left to right."

Rule 7: Is There a Risk of Collision?

The most reliable way to check is with a compass bearing:

1. Take a bearing of the other vessel with the hand-bearing compass, or line it up against a fixed point on your own boat such as a stanchion. Keep your own course steady.
2. Take another bearing a few minutes later.
3. If the bearing is not changing (or changing very little) and the vessel is getting closer, there is a risk of collision.
4. If the bearing is changing steadily, she will pass ahead or astern of you.

A useful saying is "constant bearing, decreasing range = collision". With large ships or a vessel towing, be careful: the bearing may change appreciably and a risk of collision may still exist, especially at close range. Rule 7 says that if there is any doubt, you must assume risk of collision exists, and that assumptions must not be made on scanty information, especially scanty radar information.

Worked example. At 1405 a ship is bearing 072 degrees (magnetic) at a range of 3.0 nm. At 1409 she is still bearing 072 and the range is 2.0 nm. The range has closed by 1.0 nm in 4 minutes, a closing speed of 15 knots. The time to run to a collision is 2.0 / 15 hours, about 8 minutes, so you must act in the next two or three minutes, with plenty of distance to spare. If the bearing is drifting, the direction of the drift tells you where she will pass, provided you hold a steady course. A bearing that is drawing aft (moving towards your stern) means she will pass astern of you. A bearing that is drawing forward (moving towards your bow) means she will pass ahead. For a vessel on your starboard bow, an increasing compass bearing means drawing aft; for a vessel on your port bow, a decreasing compass bearing means drawing aft.

Rule 6: Safe Speed

Every vessel must proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions. Rule 6 lists the factors: visibility, traffic density (including concentrations of fishing vessels), the manoeuvrability of the vessel (stopping distance and turning ability), at night the presence of background light such as shore lights, the state of wind, sea and current and the proximity of navigational hazards, and the draught in relation to the available depth of water. Vessels with radar must also consider its limitations.

Rule 6 gives no numbers. A common rule of thumb in fog is to go slowly enough to stop in about half the distance you can see, because the other vessel may be doing the same. For example, if visibility is 200 m and your yacht under engine needs about 20 m to stop, 4 knots is plenty safe, but a ship that needs a mile or more to stop cannot meet that rule, which is why you keep out of her way.

Give-Way and Stand-On

When two vessels are in a situation with risk of collision, the rules usually give each one a role.

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Rule 8 sets the standard for any action to avoid collision. The action must be positive, made in ample time and with due regard to good seamanship. A change of course or speed must be large enough to be readily apparent to another vessel observing visually or by radar, and a succession of small alterations should be avoided. If there is sea room, an alteration of course alone may be the most effective action, provided it is made in good time, is substantial and does not result in another close-quarters situation. The action should result in passing at a safe distance, and you must check its effectiveness until the other vessel is finally past and clear. If you need more time to assess the situation, Rule 8(e) allows you to slacken speed or take all way off by stopping or reversing.

The give-way vessel (Rule 16) must take early and substantial action to keep well clear. In practice an alteration of 30 degrees or more (the Rules give no figure; this is a widely taught rule of thumb), or a clear reduction of speed, is easy for the other vessel to see. Small, late changes of a few degrees are not visible and are dangerous. At night, a good alteration changes the lights the other vessel sees: for example, from showing her your green sidelight and masthead light to showing her only your stern light.

The stand-on vessel (Rule 17) must keep her course and speed, so that the give-way vessel can predict her movements. But:

• As soon as it becomes apparent that the give-way vessel is not taking appropriate action, the stand-on vessel may take action to avoid collision by her manoeuvre alone. She should also sound the doubt signal (at least five short and rapid blasts), which tells the other vessel she is not sure what is intended.
• If the vessels get so close that the give-way vessel's action alone cannot prevent a collision, the stand-on vessel must take the best action to avoid collision.
• In a crossing situation between two power-driven vessels, a stand-on vessel that takes action should, if the circumstances admit, not alter course to port for a vessel on her own port side (Rule 17(c)), because the give-way vessel is likely to turn to starboard and the two turns would bring them together. The best action is usually to alter to starboard or slow down.

The Steering Rules

Rule 12: Two Sailing Vessels

When two sailing vessels meet with a risk of collision:

1. Wind on different sides: the vessel on port tack (wind coming over her port side, mainsail on the starboard side) keeps clear of the vessel on starboard tack.
2. Wind on the same side: the windward vessel keeps clear of the leeward vessel.
3. If a port-tack vessel sees a vessel to windward and cannot tell which tack that vessel is on, she keeps clear.

The "tack" is decided by the side the mainsail is carried on: the windward side is the side opposite to the main boom. When running downwind with the main boom on the starboard side, you are on port tack.

How to remember it: "Starboard tack, stand on." A port-tack yacht can usually avoid a starboard-tack yacht by bearing away to pass behind her stern.

Rule 13: Overtaking

A vessel coming up on another from more than 22.5 degrees abaft (behind) her beam is overtaking. At night, an overtaking vessel would see only the stern light of the vessel ahead and neither of her sidelights.

The overtaking vessel keeps clear of the vessel being overtaken, whatever type of vessel either is. This rule comes before all others in the steering rules: a sailing yacht overtaking a slow motor boat must keep clear of the motor boat. The overtaking vessel stays the give-way vessel until she is "finally past and clear", even if her bearing changes so that she appears to be crossing.

Rule 14: Head-On

When two power-driven vessels meet on reciprocal or nearly reciprocal courses, so that each sees the other ahead (at night, both sidelights, or the masthead lights in line), both alter course to starboard and pass port to port.

Both vessels are give-way vessels. If in doubt whether it is a head-on situation, assume it is and turn to starboard. Remember: this rule applies to power-driven vessels, including a yacht under engine.

Rule 15: Crossing

When two power-driven vessels are crossing with risk of collision, the vessel that has the other on her own starboard side keeps clear and should avoid crossing ahead of the other vessel.

At night this is easy to remember using the lights:

• If you see the other vessel's red (port) sidelight, she is crossing from your starboard side: you give way. Red means stop, or "keep clear".
• If you see her green (starboard) sidelight, she is on your port side: you stand on, but watch her carefully. Green means go, carefully.

The normal action for a give-way vessel in a crossing situation is to alter to starboard and pass astern of the other vessel, or slow down.

Rule 18: Responsibilities Between Vessels (the Pecking Order)

When the overtaking, narrow-channel and traffic-separation rules do not say otherwise, the less manoeuvrable vessel generally stands on. A power-driven vessel underway keeps clear of a sailing vessel.

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Rule 18 begins with the words "except where Rules 9, 10 and 13 otherwise require", so overtaking, narrow channels and traffic separation schemes come first. Below those, the order of who keeps out of whose way is:

In addition, any vessel other than one not under command or restricted in ability to manoeuvre shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draught that is showing the signals of Rule 28. A vessel not under command or restricted in ability to manoeuvre is at the top of the list but the Rules do not rank them against each other. Rule 18 also has rules for seaplanes and wing-in-ground craft, which keep well clear of other vessels.

The practical summary for a yacht under sail: you keep clear of fishing vessels, RAM and NUC vessels, and you should avoid impeding a vessel constrained by her draught. Power-driven vessels (including a yacht under engine) keep clear of you, except in the cases governed by Rules 9, 10 and 13.

Narrow Channels and Traffic Separation Schemes (Rules 9 and 10)

• In a narrow channel or fairway (Rule 9), keep as near to the outer limit of the channel on your starboard side as is safe and practicable. Vessels under 20 metres and all sailing vessels must not impede a vessel that can only navigate safely within the channel. Fishing vessels must also not impede. For example, a yacht must not get in the way of a cross-channel ferry in the dredged channel into Portsmouth or Southampton. Do not cross a channel if it would impede such a vessel, and do not anchor in a narrow channel if you can avoid it. A vessel approaching a bend or an area where other vessels may be hidden sounds one prolonged blast, and any vessel within hearing on the other side of the bend answers with one prolonged blast.
• In a Traffic Separation Scheme (Rule 10, for example the Dover Strait), vessels follow the lanes like a dual carriageway, in the general direction of traffic flow for that lane, keeping clear of the separation line or zone and normally joining or leaving at the ends. A vessel obliged to cross the lanes should cross on a heading as nearly as practicable at right angles to the general direction of traffic flow. Yachts under 20 m and all sailing vessels must not impede the safe passage of power-driven vessels following a lane. A vessel should not use the inshore traffic zone if she can safely use the adjacent lane, but vessels under 20 m, sailing vessels and fishing vessels may use it. Rule 10 does not give a yacht any right to be in the lane, so most yachts avoid a scheme or cross it by the shortest practicable route.

In practice, near large ships in confined water, a yacht is almost always expected to keep out of the way.

Navigation Lights

Lights must be shown from sunset to sunrise and in restricted visibility by day. They tell you what a vessel is, which way she is heading and what she is doing.

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The Basic Lights

Notice that the arcs fit together: masthead 225 plus stern 135 equals 360 degrees, and the two sidelights of 112.5 degrees fill the same 225 degree sector as the masthead light. So from any angle you see either the stern light or the sidelights, but never both.

How far can the lights be seen? (Rule 22)

The Rules set minimum visibility ranges for lights, in clear weather, so you know when to expect to see each type. These depend on the vessel's length.

The practical lessons: a small yacht's sidelights may not be seen until the yacht is only a mile away, and a small boat's lights can be hard to pick out from shore lights, so never count on being seen. And you will usually see a large ship's lights long before you can make out her sidelights.

What are you looking at? Reading the lights

Work out the vessel and her direction from what you see. For a power-driven vessel under 50 m with her normal lights:

When you see a vessel at night, work through it in a fixed order: Is there a masthead light? How many? What coloured sidelight, if any? Is there a stern light? Are there any all-round lights above, below or in a vertical line? Then ask what the combination means and which way she is going, and take a bearing to see whether it is changing.

Power-Driven Vessel

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A power-driven vessel underway shows a masthead light, sidelights and a stern light. Vessels of 50 metres or more show a second, higher masthead light further aft. The two masthead lights act as a range: if they are in line, the ship is heading straight at you; if they open out, you can tell which way she is turning.

A sailing yacht motoring is a power-driven vessel and must show the masthead (steaming) light as well as her sidelights and stern light. She must not use the masthead tricolour while motoring.

Sailing Vessel

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A sailing vessel underway shows sidelights and a stern light, but no masthead light. A sailing vessel under 20 metres may instead combine them in a single tricolour lantern at the top of the mast, which is easier to see and uses less power. A sailing vessel may also show red over green all-round lights at the masthead (not with a tricolour), though few yachts do.

So at night, a red or green light with no white light above it is probably a sailing vessel, and you must think about Rule 12 or Rule 18.

Vessel at Anchor

A vessel under 50 metres at anchor shows one all-round white light where it can best be seen, usually at the masthead or hung in the forepart. Larger ships show two: one forward and a lower one aft, and usually also light up their decks. Crew are often asked to switch on the anchor light at dusk: make sure the navigation lights are off at the same time.

Other vessels with special lights

A towing vessel's two masthead lights in a vertical line are a warning to give her a very wide berth: the tow may be on a long line astern, at night with only a dim light on the end.

The exemptions for small vessels are detailed and change with length (for example, a vessel under 7 m at anchor, not in or near a narrow channel, fairway or anchorage, need not show an anchor light or shape). Use them as information, not as an excuse: showing the correct lights and shapes is safer.

Day Shapes

By day, vessels show black shapes instead of lights, hoisted where they can best be seen.

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The two shapes a yacht crew uses most are the anchor ball and the motor-sailing cone. Many yachts do not show them, but the law requires them (vessels under 7 m have some exemptions).

Special Vessels

Some vessels cannot get out of your way easily, and they show special lights and shapes to warn you. Lights for special vessels are shown in a vertical line, all-round, in addition to the normal sidelights and stern light when making way.

Not Under Command (NUC)

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A vessel that cannot manoeuvre because of some exceptional circumstance, such as an engine or steering failure. Two all-round red lights in a vertical line; by day two black balls. A memory aid: "red over red, the captain is dead". Keep well clear.

Restricted in Ability to Manoeuvre (RAM)

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A vessel whose work limits her ability to manoeuvre, such as dredging, laying cable, servicing a navigation buoy, supporting divers, or launching aircraft. Red, white, red all-round lights in a vertical line; by day ball, diamond, ball. "Red, white, red, restricted ahead." Dredgers and diving vessels may also show which side is safe to pass: two greens (or two diamonds) on the safe side, two reds (or two balls) on the obstructed side.

Constrained by Draught (CBD)

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A large power-driven vessel that cannot leave a deep-water channel because of her draught. Three all-round red lights in a vertical line; by day a cylinder. You must not impede her.

Fishing Vessels

Fishing vessels are common around the UK coast and are often mistaken for other vessels at night. Their lights have two all-round lights in a vertical line:

When making way through the water, a fishing vessel also shows sidelights and a stern light. A trawler may be towing a net hundreds of metres astern, so never pass close behind one. When her gear extends more than 150 m horizontally from the vessel, she shows an additional all-round white light in the direction of the gear (by day a black cone point up), so you know on which side the gear lies and must pass the other side. A trawler of 50 m or more also shows a masthead light abaft and higher than the green light, and a pair-trawler shows searchlights directed forward and in the direction of the other vessel. A vessel fishing with no way on, for example hauling pots, shows only the fishing lights and no sidelights. Day shape: two cones with their points together (a vessel under 20 m may show a basket instead).

Sound Signals

Sound signals are made on the whistle or horn. A short blast lasts about 1 second; a prolonged blast lasts 4 to 6 seconds. Yachts usually carry a handheld air horn.

Manoeuvring and Warning Signals (vessels in sight of one another)

These manoeuvring signals (one, two and three short) are given by power-driven vessels underway when vessels are in sight of one another and one is manoeuvring as the Rules allow or require. A sailing vessel under sail does not give them. Anyone may give the five-blast doubt signal, and a light signal of at least five short and rapid flashes may be used instead or as well. If you hear a ship sound five short blasts while you are near her, assume it is meant for you.

Fog Signals (restricted visibility)

A yacht under sail in fog sounds one prolonged blast followed by two short blasts ("Mooooo-beep-beep") at least every two minutes. Under engine, she sounds one prolonged blast. Note that a yacht under 12 metres need not carry the full signalling equipment but must make some other efficient sound signal at intervals of not more than 2 minutes. A vessel at anchor may also sound one short, one prolonged and one short blast to warn an approaching vessel of her position.

Restricted Visibility (Rule 19)

Rule 19 applies to vessels that are not in sight of one another when in or near an area of restricted visibility, for example fog. There is no give-way or stand-on vessel in fog. Every vessel must:

1. Proceed at a safe speed for the conditions, with the engine ready for immediate manoeuvre.
2. Show navigation lights, even by day, and sound the correct fog signal.
3. Keep a lookout and listen, and use radar if it is fitted. If a vessel is detected by radar alone, decide whether a close-quarters situation or risk of collision is developing, and if so act in ample time.
4. Avoid, so far as possible, altering course to port for a vessel forward of the beam (other than one being overtaken), and altering course towards a vessel abeam or abaft the beam.
5. On hearing the fog signal of another vessel apparently forward of the beam, or when you cannot avoid a close-quarters situation with a vessel forward of the beam, reduce speed to the minimum at which you can keep on course. If necessary take all way off and navigate with extreme caution until danger of collision is over.

Practical crew tasks in fog: put on lifejackets, switch on navigation lights and radar, hoist the radar reflector, post a lookout forward (away from engine noise) to listen, sound the fog signal on time (using a stopwatch), note the time and position, keep out of the shipping lanes, and keep the skipper told about every sound and echo.

Worked Example

Scenario: A Night Encounter Under Sail

You are on watch at night, sailing close-hauled on starboard tack (wind over the starboard side, main boom out to port), showing your tricolour. You see a red light, with no white light above it, about 40 degrees on your starboard bow.

1. Identify it. A red light with no masthead light is a vessel's port side and she is probably under sail. She is crossing from your starboard side towards your port side.
2. Check the risk. You take a bearing with the hand-bearing compass: 085 degrees. Three minutes later it is still 085 degrees and the light is brighter. Constant bearing and decreasing range mean a risk of collision.
3. Work out the rule. You are both sailing. She is close-hauled heading across your bow with her sails on her starboard side, so the wind is on her port side: she is on port tack. Under Rule 12, port tack gives way to starboard tack. You are the stand-on vessel.
4. Report. "Skipper, sailing vessel on the starboard bow, about a mile, bearing steady. She's on port tack, we're stand-on."
5. Stand on. Hold your course and speed so she can predict your movement. Keep checking the bearing.
6. If she does not act. If she has not altered when she is about half a mile away, the skipper may shine a torch on your sails to make you visible and sound five short blasts. If a collision still looks likely, take avoiding action. Here, the safest action is a substantial turn to starboard (luff up or tack, or start the engine and turn), which takes you astern of her track. Avoid turning to port, which would take you towards the side she is heading.
7. Outcome. She bears away and passes astern of you. You record the encounter in the log.

Scenario: Under Engine in a Harbour Approach

You are motoring up a buoyed channel into harbour at 5 knots in daylight, so you are a power-driven vessel and show a cone (point down) only if you also have sails up. Ahead, a motor boat is coming straight towards you, also using the channel. You can see both sides of her hull. This is a head-on situation (Rule 14): both vessels turn to starboard. The helm turns 20 to 30 degrees to starboard, enough to be obvious, and you pass port to port. You are also following Rule 9 by keeping to the starboard side of the channel. Behind you, a 150 m ferry with three red lights at night (or a cylinder by day) is constrained by draught. You keep well to the edge of the channel so you do not impede her.

More Scenarios and Exam Practice

Scenario 1: the constant bearing

You are on the helm in daylight, and the skipper has asked you to call any vessel that might be a concern. A ferry is on your starboard bow. You take a hand-bearing compass reading: 072M at 1405, 072M at 1407, 073M at 1409. The bearing is not changing and the ferry is clearly bigger. This is the classic sign of risk of collision. Call the skipper: "Ferry, bearing zero seven two magnetic, constant, getting closer." Your yacht is motoring, so you are a power-driven vessel, and you are the give-way vessel because the ferry is on your starboard side and you are on crossing courses (Rule 15). Had you been under sail only, the ferry would be the give-way vessel under Rule 18, but you would still keep a close watch and be ready to act. The skipper alters course to starboard early and substantially, so that the ferry sees the change and the bearing starts to move aft.

Scenario 2: lights at night

At night you see a red sidelight and a white masthead light of a power-driven vessel on your starboard bow, and the bearing is steady. Seeing her red (port) light means she is on your starboard side, crossing, so you are the give-way vessel: "If to starboard red appear, it is your duty to keep clear." Alter to starboard early and pass astern of her. If instead you see her green light on your port bow with a steady bearing, you are the stand-on vessel and should hold course and speed, ready to act if she does not.

Scenario 3: the fishing boat

A fishing boat shows green over white all-round lights, which means a trawler, and is moving across your bows. Under Rule 18 a sailing vessel underway must keep out of the way of a vessel engaged in fishing, so take early action and pass astern of her. Fishing vessels also have a duty not to impede vessels in narrow channels, but do not rely on that. A vessel fishing other than trawling shows red over white.

Scenario 4: motorsailing

A yacht with a mainsail up and the engine running is a power-driven vessel while the engine is in use. If you are motorsailing, you must show a black cone, point down, in the forward part of the vessel by day. You do not have the privileges of a sailing vessel, so you give way to a sailing vessel and you must obey the power-driven steering rules.

Scenario 5: crossing a traffic separation scheme

The skipper decides to cross the Dover Strait scheme. The lanes run roughly 045 and 225 degrees True, so the crossing heading is 135 or 315 degrees True. You are the watch keeper. Ships in the lanes may be making 15 to 20 knots, and you want to know how long the crossing takes. If the lane zone is 6 nm wide and the yacht makes 5 knots, you are in the lanes for about 6 / 5 = 1.2 hours (72 minutes). You keep a lookout for ships on both sides, check the bearing of each approaching ship every few minutes, and report: "Ship, port bow, bearing zero-nine-zero magnetic, steady, range four miles." The skipper holds the heading at 90 degrees to the lane (the Rule is about the heading, not the track), because the other ships expect it, and alters course early and substantially if a close-quarters situation develops.

Scenario 6: the narrow channel

You are under sail in a buoyed channel into a harbour and a coaster is coming up astern, showing two masthead lights nearly in line (the after one higher) and both her red and green sidelights, so she is over 50 m long and heading almost straight along the channel towards your stern. As a sailing vessel you must not impede a vessel that can safely navigate only inside the channel. You keep to the starboard side of the channel, as far over as is safe, and avoid tacking across her path. You listen for her signals: if she sounds two prolonged and one short blast she intends to overtake you on your starboard side, and you can agree with one prolonged, one short, one prolonged and one short. Then you stay to starboard of the channel.

Learning the lights quickly

Walk through the lights in a fixed order: first the number of masthead lights (one or two), then the sidelights (red on port, green on starboard), then the stern light, then any all-round lights above the masthead. For a small power-driven vessel under 12 m, the masthead light and stern light may be combined into one all-round white light, with sidelights. A sailing vessel under 20 m may use a combined tricolour at the masthead. A vessel at anchor shows all-round white lights, one if she is under 50 m long.

Writing up the watch

When the skipper asks you to keep the log, record the time, the vessel's description, the bearing and range, her aspect, and what action was taken. Over a passage this record is useful evidence that a lookout was kept, and it helps you learn to judge how quickly a bearing changes.

What the instructor expects

• You keep a lookout all round, including astern, and you report vessels in a useful way: type, bearing, range, aspect and bearing movement.
• You can name the give-way and stand-on vessel in a simple scenario and say what each should do.
• You do not act on your own to alter course without telling the skipper unless there is immediate danger; you can warn the helm calmly and clearly.
• You can recognise the day shapes and lights without hesitating, and say what the vessel is doing.

Common Mistakes

Late Action

A give-way vessel that waits too long and then makes a small change of course leaves the other vessel uncertain and creates a close-quarters situation. Act early, and make the change large enough to be obvious: 30 degrees or more, or a turn to show the other vessel a different light at night.

Port and Starboard Confusion

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Port is the left side looking forward and its light is red. Starboard is the right side and its light is green. Memory aids: "Is there any red port left?" and "port is shorter than starboard, like left is shorter than right." When you see a red light, you are looking at the vessel's port side.

"Sail Always Has Right of Way"

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This is a dangerous myth. A sailing vessel must keep clear when she is overtaking, must not impede large vessels in narrow channels and traffic lanes, and must keep clear of fishing, RAM and NUC vessels. A yacht with her engine running is a power-driven vessel. And a ship travelling at 20 knots may not see a small yacht at all, so even when the rules say she should give way, the yacht must be ready to take action. Never assume the other vessel has seen you.

Other Mistakes

• Motor-sailing but showing sailing lights. If the engine is driving the boat, show the steaming light and use the power-driven vessel rules.
• Not looking under the genoa or astern. Most "the ship came out of nowhere" stories begin here.
• Ruining night vision with white torches and phone screens. Use red lights.
• Mistaking a fishing vessel's lights for an anchored vessel or a buoy. Learn green over white and red over white.
• Ignoring fog signals. If you hear a fog signal forward of the beam and cannot see the vessel, the skipper should slow to the minimum speed needed to steer and be ready to stop.
• Not checking the bearing. Guessing whether a ship will pass ahead or astern is unreliable. Take bearings.

Summary

• The COLREGs apply to every vessel. Rule 2 means you must always act to avoid collision, whatever the rules say about who should give way.
• Keep a proper lookout all round, all the time, including under the genoa and astern. Protect your night vision.
• If the compass bearing of an approaching vessel does not change, there is a risk of collision.
• The give-way vessel acts early and substantially. The stand-on vessel holds course and speed but must act if collision becomes likely.
• Sail meets sail: port tack gives way to starboard tack; windward gives way to leeward.
• Overtaking vessels keep clear, whatever their type.
• Power meets power head-on: both turn to starboard. Crossing: the vessel with the other on her starboard side gives way.
• Power gives way to sail, but sail keeps clear of fishing, RAM and NUC vessels, and must not impede large vessels in channels.
• Lights: masthead white 225 degrees, sidelights red and green 112.5 degrees, stern white 135 degrees. A sailing vessel has no masthead light. An anchored vessel shows one all-round white light.
• Day shapes: ball at anchor, cone point down when motor-sailing.
• Special vessels: NUC red over red, RAM red-white-red, CBD three reds, trawler green over white, other fishing red over white.
• Rule 8: action to avoid collision must be positive, early and large enough to be readily apparent; a series of small alterations is not acceptable.
• Rules 9 and 10: keep to the starboard side of a narrow channel, do not impede large vessels there or in a traffic lane, and cross a scheme on a heading at right angles.
• Rule 19: in fog nobody is stand-on; slow down, sound the fog signal, and avoid turning to port for a vessel forward of the beam.
• Sound signals: one short is starboard, two short is port, three short is astern, five or more is doubt. In fog, a yacht under sail sounds one prolonged and two short.

Check Your Understanding

1. Two sailing yachts are approaching each other. Yacht A has the wind on her starboard side and Yacht B has it on her port side. Which yacht gives way?

Answer: Yacht B, which is on port tack, gives way to Yacht A on starboard tack (Rule 12).

1. You are on watch and take three bearings of a ship over six minutes: 210, 210 and 211 degrees. The ship is getting closer. What does this tell you and what should you do?

Answer: The bearing is almost constant while the range decreases, so there is a risk of collision. Tell the skipper at once.

1. Your yacht is sailing with the engine running in gear. What type of vessel are you under the COLREGs, and what day shape should you show?

Answer: A power-driven vessel. By day you should show a black cone, point downwards, forward.

1. At night you see a single white light ahead, with no other lights, and you are slowly getting closer. Give two possible explanations.

Answer: It could be the stern light of a vessel you are overtaking (so you must keep clear), or the all-round white anchor light of a vessel at anchor. It could also be a small vessel's all-round white light. Watch carefully and take bearings to find out.

1. You see a red light over a red light, all-round, on a vessel ahead. What does it mean and what should you do?

Answer: Not under command: the vessel cannot manoeuvre as required by the rules. Keep well clear of her.

1. What lights does a trawler show at night, and how is that different from other fishing vessels?

Answer: A trawler shows green over white all-round lights. Other fishing vessels show red over white. Both show sidelights and stern light when making way.

1. A ship sounds five short blasts as your yacht crosses ahead of her. What does it mean?

Answer: It is the doubt signal: she does not understand your intentions or doubts you are taking enough action to avoid a collision. Take clear, early action to keep out of her way.

1. In fog you hear one prolonged blast followed by two short blasts, repeated every two minutes. What could it be?

Answer: A sailing vessel underway, or a vessel that is fishing, not under command, restricted in ability to manoeuvre, constrained by her draught, or towing.

1. A power-driven vessel is crossing from your starboard side and you are also under engine. Which of you gives way, and what is the usual action?

Answer: You give way, because she is on your starboard side (Rule 15). The usual action is an early, substantial turn to starboard to pass astern of her, or slowing down.

1. Why is "sail always has right of way" a dangerous idea?

Answer: There is no right of way, only duties. Sail must keep clear when overtaking, must not impede large vessels in channels or traffic schemes, and must keep clear of fishing, RAM and NUC vessels. A yacht under engine is a power-driven vessel. And a large ship may not see you, so you must always be ready to act to avoid a collision.

1. You are crewing a yacht under sail alone and a power-driven ship is overtaking you. Who must keep clear?

Answer: The ship, because any vessel overtaking another must keep clear (Rule 13), whatever the type. The yacht, as stand-on vessel, should hold course and speed.

1. What should you report to the skipper when you sight a vessel on your bow?

Answer: What she is, which direction she is in (bearing), how far away, which way she is heading (aspect), whether the bearing is changing, and any lights or shapes you can see.