COLREGS Navigation Lights and Shapes - Complete Reference

Prerequisites

• Competent Crew knowledge of lookout duties, basic port and starboard, and recognising other vessels.
• Basic understanding of sailing on port and starboard tack and of points of sail.
• Ability to take a bearing with a hand-bearing compass (Position Fixing lesson).
• Day Skipper Practical candidates must have theory to Shorebased level — the International Regulations for Preventing Collisions at Sea (COLREGs) are examined both in the shorebased course and orally on the practical.

Learning Objectives

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

• State the purpose of the COLREGs and the key general rules (Rules 2, 5, 6, 7 and 8).
• Determine whether risk of collision exists, using compass bearings and radar.
• Apply the steering rules for sailing vessels (Rule 12), overtaking (13), head-on (14) and crossing (15).
• Carry out the duties of the give-way (16) and stand-on (17) vessel.
• Apply the responsibilities between vessels (Rule 18).
• Conduct yourself correctly in restricted visibility (Rule 19).
• Recognise the lights and shapes of vessels likely to be met in coastal waters.
• Know the manoeuvring, warning and fog sound signals.
• Describe your actions clearly and correctly in an examiner's scenario.
• Work out the closest point of approach and time to it from two or more bearings and ranges, and decide when to act.
• Identify the vessel and her heading from any combination of lights, using the Rule 22 ranges to judge when you should see them.
• Plan a crossing of a traffic separation scheme and state the duties of a small yacht in narrow channels (Rules 9 and 10).

RYA syllabus mapping (Day Skipper shorebased and practical, Navigation and Safety): this lesson covers the Day Skipper requirement to apply the collision regulations, namely Rules 2 and 5 to 8 (responsibility, lookout, safe speed, risk of collision, action to avoid collision), Rules 9 and 10 (narrow channels and traffic separation schemes, in outline), Rules 12 to 18 (steering and responsibilities), Rule 19 (restricted visibility), and the lights, shapes and sound signals in Rules 20 to 37 that a coastal yachtsman meets. The oral examiner may ask you to describe actions in any scenario, so practise speaking your answer.

The Purpose and Structure of the COLREGs

The International Regulations for Preventing Collisions at Sea 1972 (as amended) apply to all vessels on the high seas and connected navigable waters — from supertankers to dinghies. In UK waters they are given legal force by the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations; breaching them is an offence. Local harbour by-laws can add to them (for example, small craft keeping out of a fairway), and you must know local rules as well.

The Rules are arranged in parts:

Rule 2 — Responsibility

Nothing in the Rules excuses a vessel from the consequences of neglecting any precaution required by ordinary seamanship, and a departure from the Rules may be necessary to avoid immediate danger. In short: you never have "right of way". You have obligations, and you must use common sense.

Key definitions (Rule 3)

• Power-driven vessel: any vessel propelled by machinery. A yacht sailing with the engine running in gear is a power-driven vessel.
• Sailing vessel: under sail only.
• Vessel engaged in fishing: fishing with nets, lines or trawls that restrict manoeuvrability — not trolling lines.
• Not under command (NUC): unable to manoeuvre due to exceptional circumstance (e.g. steering failure).
• Restricted in ability to manoeuvre (RAM): limited by the nature of her work (dredging, cable laying, servicing a navigation mark, replenishing at sea, towing that restricts her).
• Constrained by draught (CBD): a power-driven vessel severely restricted by her draught in relation to the available depth and width of water.
• Underway: not at anchor, made fast to the shore or aground — you can be underway without making way.
• Making way: moving through the water. A yacht drifting or hove-to with no speed through the water is underway but not making way, which affects her lights and fog signal.
• Length and breadth: the vessel's overall length. Many Rules change at 7 m, 12 m, 20 m, 50 m and 100 m.
• In sight of one another: only when one can be observed visually from the other. Radar contact alone is not being in sight, and then Rule 19 applies in restricted visibility.
• Vessel engaged in towing: the Rules treat a vessel towing so that she and her tow cannot deviate from their course as RAM.
• Restricted visibility: any condition in which visibility is restricted by fog, mist, falling snow, heavy rain, sandstorms or similar.

The Conduct Rules in Any Visibility

Rule 5 — Lookout

Every vessel shall at all times maintain a proper lookout by sight and hearing and by all available means (radar, AIS, VHF) to make a full appraisal of the situation and of the risk of collision. On a yacht, the biggest blind spot is under the genoa to leeward: check it regularly, or assign someone to.

A proper lookout on a coastal yacht means:

• a dedicated person, who is not also steering, navigating or doing sail trim unless the visibility and traffic are very light;
• all-round scans at least every 5 minutes by day and at night, including astern, and more often in busy water;
• using binoculars and a hand-bearing compass to identify and to judge movement, and radar and AIS as extra aids;
• keeping good night vision, with red light below and on deck;
• listening for horns, fog signals and engines, with the engine off or the lookout forward in fog;
• reporting in a standard form: what, where (relative bearing or clock position), how far, what doing, and whether the bearing is steady.

Rule 6 — Safe speed

Every vessel shall 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 conditions. Factors include visibility, traffic density, the vessel's manoeuvrability, background lights at night, wind, sea and current, the proximity of hazards, and the draught versus available depth. Vessels with radar must also consider its limitations.

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Rule 6 itself gives no figures. The diagram's "stop within half the visible distance" is a widely taught rule of thumb (it allows for another vessel doing the same from the other side), not the text of the Rule — but it is a sound way to judge speed in fog.

Rule 7 — Risk of collision

Use all available means to determine if risk of collision exists; if in doubt, assume it does. The key test: if the compass bearing of an approaching vessel does not appreciably change, risk of collision exists. Even with an appreciable bearing change, risk may exist with a very large vessel, a tow, or at close range.

How to check on a yacht:

1. Take a hand-bearing compass bearing of the other vessel, or line it up against a stanchion or winch while holding the same course and seat.
2. Repeat after a few minutes.
3. If the bearing is steady (or its line against your boat's fixed reference stays still) and the range is closing, there is risk of collision.

A sailing yacht has many blind spots, under the headsail and behind the mainsail, so more vigilance is required than on a motor boat, and the lookout must remember to look astern. Make your intentions early and clear: a course alteration is always easier for the other vessel to spot than a change of speed. The classic Day Skipper picture is a boat on starboard tack standing on because she is the stand-on vessel, while the boat on port tack flying a spinnaker has not seen her; leave the decision too late and a collision may be unavoidable, and under Rule 2 every vessel has an absolute obligation to avoid a collision, stand-on or not. Local harbour by-laws (speed limits, small craft channels, prohibited areas) apply in addition to the Rules.

Use AIS CPA and TCPA (closest point of approach, time to CPA) as an aid, not a substitute — many small craft do not transmit AIS.

Worked example: CPA from two observations. Your yacht is heading 000M at 5 knots. At 1000 a ship bears 040M at 6.0 nm. At 1006 she bears 043M at 4.8 nm.

1. Convert each observation to a position relative to your yacht. At 1000: east = 6.0 x sin 40 = 3.86 nm, north = 6.0 x cos 40 = 4.60 nm. At 1006: east = 4.8 x sin 43 = 3.27 nm, north = 4.8 x cos 43 = 3.51 nm.
2. The relative movement in 6 minutes is 0.59 nm west and 1.09 nm south, about 1.23 nm, so the relative speed is 12.3 knots.
3. Extend the line. It passes about 1.2 nm from your yacht (the closest point of approach, CPA) and the ship reaches that point about 23 minutes after 1006, at about 1029, on your starboard side and slightly astern.
4. The bearing has drawn aft by 3 degrees in 6 minutes: a small but real change. A CPA of 1.2 nm is acceptable for a yacht and a ship in open water, but it changes if either vessel alters, so keep plotting and keep the margin under review.

On a plotter or by hand, the same answer comes from a relative-motion plot. Draw the first position of the ship relative to you, then the second, join and extend the line, and measure the nearest distance to your own position. If your boat alters course, the plot must be restarted.

Rule 7(c) also warns against assumptions made on scanty information, especially scanty radar information: two blips on a small radar screen are not a reliable plot, so keep plotting until the trend is clear.

Rule 8 — Action to avoid collision

Any action taken must be:

• positive — clear and decisive;
• made in ample time — early, well before close quarters;
• with due regard to good seamanship;
• large enough to be readily apparent to another vessel observing visually or by radar — a succession of small alterations should be avoided. In practice, at least 30 degrees, and often 60 to 90 degrees;
• resulting in passing at a safe distance;
• checked for effectiveness until the other vessel is past and clear.

Slowing down, stopping or going astern are also legitimate avoiding actions.

Rules 9 and 10 — Narrow channels and traffic separation schemes

• Rule 9: keep as near to the outer limit of a narrow channel or fairway which lies on your starboard side as is safe and practicable. Vessels under 20 m and sailing vessels shall not impede a vessel which can navigate safely only within the channel; nor shall a vessel engaged in fishing. Do not cross a channel if it impedes such a vessel. Do not anchor in a narrow channel if the circumstances admit. In a channel where overtaking can take place only if the vessel to be overtaken has to take action, the overtaking vessel sounds the Rule 34(c) signals (see Sound Signals) and the other agrees. A vessel nearing a bend or an area where other vessels may be hidden sounds one prolonged blast, answered by one prolonged blast from any vessel within hearing.
• Rule 10: in a traffic separation scheme, use the correct lane in the general direction of traffic flow for that lane; keep clear of the separation line or zone so far as practicable; normally join or leave at the ends of a lane, and if you join or leave from the side, do so at as small an angle to the general direction of flow as practicable. A vessel shall, so far as practicable, avoid crossing lanes, but if obliged to cross she shall do so on a heading as nearly as practicable at right angles to the general direction of traffic flow (the heading, not the track, is at right angles). A vessel shall not use an inshore traffic zone when she can safely use the adjacent lane, but vessels under 20 m, sailing vessels and vessels fishing may use it. A vessel other than a crossing, joining or leaving vessel shall not normally enter the separation zone or cross a separation line except in an emergency or to engage in fishing within the zone. Vessels under 20 m and sailing vessels shall not impede the safe passage of a power-driven vessel following a traffic lane. Avoid anchoring in a scheme or near its terminations.

Steering Rules When in Sight of One Another

The order of responsibilities (Rule 18)

Except where Rules 9, 10 and 13 require otherwise, vessels give way to those less able to manoeuvre.

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In addition: any vessel other than NUC or RAM shall, if circumstances permit, avoid impeding the safe passage of a vessel constrained by her draught. Seaplanes and WIG craft keep clear of all vessels. And — overriding everything above — an overtaking vessel always keeps out of the way (Rule 13).

Practice: applying the hierarchy

Rule 12 — Two sailing vessels

1. When each has the wind on a different side, the vessel with the wind on the port side keeps out of the way (port tack gives way to starboard tack).
2. When both have the wind on the same side, the windward vessel keeps out of the way of the leeward vessel.
3. If a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty on which side the other has the wind, she shall keep out of the way.

The "windward side" is the side opposite to that on which the mainsail is carried (for a square-rigger, the largest fore-and-aft sail). A boat running dead downwind with the main to starboard has the wind on the port side.

Practice: who gives way between two sailing vessels?

To decide the tack of a boat at a distance, look at which side her mainsail is: the side opposite the boom is her windward side. A boat running dead downwind with her boom out to starboard is on port tack.

Rule 13 — Overtaking

Any vessel overtaking any other shall keep out of the way of the vessel being overtaken — regardless of type. A sailing yacht overtaking a slow motor boat must keep clear.

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• You are overtaking if you approach from more than 22.5 degrees abaft the other vessel's beam — at night you would see only her sternlight and none of her sidelights. In numbers: if the other vessel is heading 000, you are overtaking when you are on a bearing from her between 112.5 and 247.5 degrees, a sector of 135 degrees (the arc of her sternlight).
• If in doubt, assume you are overtaking.
• The overtaking vessel remains the give-way vessel until finally past and clear, even if the bearing later changes into a crossing situation.

Rule 14 — Head-on (power-driven vessels)

When two power-driven vessels meet on reciprocal or nearly reciprocal courses with risk of collision, each alters course to starboard so they pass port to port.

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• You are head-on if you see the other vessel ahead with her masthead lights in line or nearly in line and/or both sidelights; by day, the corresponding aspect.
• If in doubt, assume it is head-on and act accordingly.
• The alteration should be bold and early. One short blast signals "I am altering my course to starboard".
• Rule 14 applies only between power-driven vessels. A sailing yacht meeting a ship head-on follows Rule 18 (the ship should keep clear), but a prudent yacht skipper keeps well clear of big ships anyway.

Rule 15 — Crossing (power-driven vessels)

When two power-driven vessels are crossing with risk of collision, the vessel which has the other on her own starboard side keeps out of the way and shall, if circumstances permit, avoid crossing ahead.

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At night, if you see another vessel's red (port) sidelight, you are probably the give-way vessel: "If to starboard red appear, 'tis your duty to keep clear." Seeing her green light, you are probably the stand-on vessel: "Green to green, or red to red, perfect safety, go ahead" applies to vessels passing clear of each other.

The best give-way action is usually a bold alteration to starboard to pass astern of the other vessel, or a reduction of speed.

Rule 16 — Action by give-way vessel

Take early and substantial action to keep well clear.

Rule 17 — Action by stand-on vessel

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The stand-on vessel's duties change as the situation develops:

1. Initially: keep course and speed, so the give-way vessel can predict your movement. Monitor bearings.
2. When it becomes apparent the give-way vessel is not taking appropriate action: you may take action to avoid collision by your manoeuvre alone. Sound at least five short and rapid blasts first (Rule 34(d)) to signal doubt. If you are power-driven in a crossing situation, do not alter to port for a vessel on your own port side if the circumstances permit.
3. When collision cannot be avoided by the give-way vessel alone: you must take the action that will best aid to avoid collision.

Stand-on never means "do nothing to the end". Many collisions occur when both vessels wait for the other.

Restricted Visibility (Rule 19)

Rule 19 applies to vessels not in sight of one another in or near an area of restricted visibility. In fog there is no stand-on or give-way vessel — every vessel must take avoiding action.

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• Proceed at a safe speed adapted to the conditions; power-driven vessels have engines ready for immediate manoeuvre.
• If a vessel is detected by radar alone, determine whether a close-quarters situation or risk of collision is developing; if so, take avoiding action in ample time.
• Avoid, so far as possible: an alteration to port for a vessel forward of the beam (other than one being overtaken); and an alteration towards a vessel abeam or abaft the beam.
• On hearing the fog signal of another vessel apparently forward of your beam, or being unable to avoid a close-quarters situation with a vessel forward of the beam, reduce speed to the minimum at which you can keep your course. If necessary take all way off, and navigate with extreme caution until danger is over.

Practical fog seamanship for a yacht: switch on navigation lights, hoist the radar reflector, sound the fog signal, post a lookout (and a listener forward, away from engine noise), get lifejackets on and the liferaft ready, fix your position, consider moving into shallow water where ships cannot go, and keep out of shipping lanes.

The RYA fog checklist

The Day Skipper practical course notes begin with the only reliable rule: it is never advisable to set out in fog. If you are caught out at sea:

1. Fix your position at once, by every means available, and keep the plot going.
2. Listen on the port operations frequency for commercial traffic movements, and if there is any likelihood of shipping in your vicinity monitor Channel 13, the bridge-to-bridge channel.
3. Hoist the radar reflector and switch on the navigation lights.
4. Sound the fog signal at intervals of not more than two minutes: one prolonged blast under power, one prolonged and two short under sail. Then stop and listen.
5. Muster the crew on deck in lifejackets, with the liferaft ready.
6. If you have radar, keep a constant, experienced radar watch; remember that a yacht's own radar sees only a few miles and that a large ship may not hear your horn.
7. Get out of the shipping lanes, and find and follow a depth contour that keeps you in water too shallow for ships. Consider anchoring in shallow water clear of traffic until the fog lifts.
8. Where possible, do not set a course directly for a port entrance. Aim off deliberately to one side, so that when you reach the coast you know which way to turn, and so that an error does not put you on the wrong side of the entrance, directly in the path of commercial vessels using it.

Bear in mind that large vessels may not hear your signals and cannot stop quickly; the safe place for a yacht in fog is where they cannot go.

Lights and Shapes

Lights are shown from sunset to sunrise and in restricted visibility; shapes by day. Recognising them tells you what a vessel is, which way she is heading, and what she is doing.

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Basic lights

Visibility ranges (Rule 22) and reading the lights

A yacht's sidelights (1 to 2 nm) will not be seen by a ship from far away, and a small yacht's lights are easily lost against shore lights. Never assume you have been seen at night.

To read a vessel's lights, work through them in the same order each time: masthead lights (how many?), sidelights (which colours), sternlight, then any all-round lights above or below. Then:

Power-driven vessels underway

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• Masthead light, sidelights and sternlight.
• A vessel 50 m or more shows a second masthead light, abaft and higher than the forward one. When the two masthead lights appear one directly above the other, the ship is heading directly towards (or away from) you; if they open out to one side, she is not heading straight at you.
• Under 12 m may show an all-round white plus sidelights instead.

Sailing vessels underway

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• Sidelights and sternlight only — no masthead light.
• Under 20 m, these may be combined in a masthead tricolour.
• Optional: all-round red over green at the masthead (not with a tricolour).
• Under 7 m, if not practicable, have a white torch ready.
• When motor-sailing, you are a power-driven vessel: show a steaming (masthead) light, and by day a cone point down forward. Never use the tricolour when motoring.

Special vessels

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Memory aids: "Red over red, the captain is dead" (NUC). "Red, white, red — restricted ahead" (RAM). "White over red, pilot ahead". "Green over white, trawling at night". "Red over white, fishing at night".

Day shapes

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All shapes are black and hoisted where best seen, usually in the forward rigging. The Rules give small vessels some exemptions (for example, a vessel under 7 m at anchor away from a narrow channel, fairway or anchorage need not show an anchor light or shape), but showing the anchor ball and the motor-sailing cone is good practice and is expected in many harbours.

Sound Signals

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A short blast lasts about one second; a prolonged blast four to six seconds.

Manoeuvring and warning signals (vessels in sight of one another)

Manoeuvring signals (one, two and three short) are made by power-driven vessels; a sailing yacht under sail does not make them, but any vessel may make the five-short warning.

Fog signals (restricted visibility), at intervals of not more than 2 minutes

Vessels under 12 m need not give the full signals but must make some other efficient sound signal at intervals of not more than 2 minutes. Vessels of 12 m and over must carry a whistle and a bell (the bell for use at anchor and aground), and vessels of 100 m and over a gong as well.

Distress Signals (Rule 37 and Annex IV)

Rule 37 says a vessel in distress and requiring assistance shall use the signals in Annex IV. The main ones, which any skipper should recognise, are:

• A gun or other explosive signal fired at intervals of about a minute.
• A continuous sounding with any fog-signalling apparatus.
• Rockets or shells throwing red stars, fired one at a time at short intervals.
• A signal sent by radiotelegraphy or any other method consisting of the group SOS in the Morse code.
• A radiotelephone message consisting of the spoken word MAYDAY.
• The International Code signal of distress indicated by flags N and C.
• A square flag having above or below it a ball or anything resembling a ball.
• Flames on the vessel (such as from a burning tar barrel or oil barrel).
• A rocket parachute flare or a hand flare showing a red light.
• A smoke signal giving off orange-coloured smoke.
• Slowly and repeatedly raising and lowering arms outstretched to each side.
• The radiotelephone alarm signal, a DSC distress alert on VHF, and an EPIRB signal.
• Approved signals transmitted by radiocommunication systems, including SART.
• A dye marker, and a piece of orange canvas with a black square and circle.

Rule 36 also allows any vessel to attract attention by light or sound signals that cannot be mistaken for any authorised signal, and to direct a searchlight beam in the direction of danger without embarrassing any vessel. Do not use a strobe light or other lights that can be mistaken for aids to navigation. Making a Mayday call by radio is covered in the radio and GMDSS material.

Worked Example — The Container Ship

You are sailing on starboard tack at 6 knots in the Channel. A container ship is approaching from your starboard bow on a crossing course. Successive bearings are steady at 040 degrees relative. Range 4 miles and closing.

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• Status: under Rule 18 the power-driven ship should keep out of the way of a sailing vessel, so you are technically the stand-on vessel — unless the ship is in a TSS lane (Rule 10) or a narrow channel (Rule 9), where you must not impede her.
• Reality: a ship at 20 knots closes 4 miles in about 12 minutes (a little less allowing for your own speed). Her bridge may not have seen you; a yacht is a poor radar target. The RYA course notes make the ship's position plain: she has a large turning circle, is slow to accelerate, decelerate and stop, her actions have to be planned well ahead and may be irreversible once taken, and visibility from the bridge is very limited, with a blind arc ahead that can extend for several ship lengths. Prudent yacht skippers keep well clear. A useful exercise is to imagine that your own boat draws ten metres and look at the chart again: a wide expanse of water suddenly becomes a very narrow channel, which is exactly how it looks to the ship.
• Action: keep course and speed while monitoring. If she shows no sign of altering by about 2 miles, call her on VHF Channel 16 (or use AIS details / DSC), and if still in doubt, sound five short blasts and take bold action yourself: for a vessel on your starboard side, alter to starboard (luff, tack or start the engine and turn) to pass astern of her, and make the alteration large and obvious. Never alter to port across her bow. If you cannot turn in time, slow down or stop by easing the sheets, since Rule 8(e) allows you to slacken speed or take all way off.

Worked Example — A Fog Signal Ahead

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You are motoring at 5 knots in fog with visibility 100 m. You hear one prolonged blast apparently fine on the starboard bow; there is nothing on radar. Rule 19(e) applies: reduce to the minimum speed to hold your course, take all way off if necessary, sound your own fog signal (one prolonged, as a power-driven vessel making way — or two prolonged if stopped), put extra lookouts and listeners forward, and navigate with extreme caution until the danger is past. Do not assume no radar echo means no vessel.

Answering the Examiner

On a Day Skipper practical, the skipper is often asked to explain what a situation is and what they will do. Give a structured, decisive answer.

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1. Identify: what is it, which way is it heading, which lights or shapes can I see?
2. Classify: is there risk of collision (bearing steady)? Which rule applies? Am I give-way or stand-on?
3. Monitor: what am I watching for, and how?
4. Act: what will I do, and when — "early and substantial", "readily apparent", "at least 30 degrees".

For example: "I can see a single masthead light, a red sidelight and nothing else, bearing steady on my starboard bow. It is a power-driven vessel under 50 m, crossing from starboard to port. I am motoring, so I am a power-driven vessel and give way under Rule 15. I will alter boldly — about 60 degrees to starboard — now, to pass well astern, and hold the new course until she is past and clear."

Further Scenarios and Exam Practice

Scenario: narrow channel

You are under sail in a buoyed channel 150 m wide in the approaches to a port, and a ship of 8 m draught is approaching from astern. Rule 9 says you must not impede a vessel that can safely navigate only within the channel. A sailing vessel under 20 m must not impede such a vessel. Keep to the starboard side of the channel, consider leaving the channel entirely if depth allows, and listen on the port VHF working channel for port movements. The ship will sound one prolonged blast when approaching a bend where other vessels may be hidden (Rule 34(e)), and at least five short and rapid blasts if she doubts your intentions (Rule 34(d)).

Scenario: traffic separation scheme

You want to cross a separation scheme. Rule 10 says cross as nearly as practicable at right angles to the general direction of traffic flow, so head the boat at 90 degrees to the lanes even if the tide carries you diagonally; what matters is the heading, not the track. Avoid crossing where lanes converge if you can, and do not enter the separation zone except to cross, join or leave. A vessel under 20 m or a sailing vessel must not impede the safe passage of power-driven vessels following a lane.

Scenario: three bearings

A vessel is on your starboard bow. Your three bearings: 045M, 045M, 046M over 6 minutes, and the range reduces from 4 nm to 2.8 nm. The bearing is steady, so there is risk of collision. Work out the closing speed: 1.2 nm in 6 minutes is 12 knots. If the relative closing speed is 12 knots and the range is 2.8 nm, the vessels meet in 2.8 / 12 = 0.23 hours, about 14 minutes. Act now: in about 5 minutes you will be too close to make a safe alteration. Alter course to starboard by at least 30 degrees so the other vessel can see the change.

Scenario: safe speed in poor visibility

Visibility is 0.5 nm in fog and your boat makes 6 knots. A yacht can stop within a few boat lengths; a large ship can need a mile or more. The factors in Rule 6 include visibility, traffic density, manoeuvrability, background light, the state of the sea and the radar. In fog you reduce speed, post a lookout on the bow, switch on the radar if fitted, make the required sound signals, and listen for fog signals. If a signal is heard forward of the beam, and you cannot avoid a close-quarters situation, reduce to the minimum speed at which you can keep steerage and navigate with extreme caution until the danger is over.

Light recognition drill

Say aloud the vessels that show: one white masthead light, two sidelights and a stern light (a power-driven vessel under 50 m); two white masthead lights in a vertical line (a power-driven vessel over 50 m, the after one higher); red over green all-round (a sailing vessel, optional, at the masthead); green over white (a trawler); red over white (a vessel fishing other than trawling); red over red (not under command); red, white, red (restricted in her ability to manoeuvre); and three red lights in a vertical line (constrained by her draught). Test yourself in a blacked-out room using a torch, by sketching the lights.

How to answer an oral question

Use the format: identify, state the rule, state the action. For example: "I see a green sidelight and a white masthead light on my port bow, constant bearing: this is a power-driven vessel crossing from my port side on a collision course. I am a sailing vessel, so she must keep out of my way under Rule 18 and I am the stand-on vessel under Rule 17. I will keep my course and speed, but I will take avoiding action under Rule 17(a)(ii) if she does not act. I will call the skipper, note the bearings, and sound five short blasts if she gets close."

Common Mistakes

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• Small alterations: a 10 degree change is invisible at 2 miles. Make it at least 30 degrees, and obvious.
• Thinking stand-on means do nothing: Rule 17 requires you to act if the give-way vessel does not.
• Crossing ahead of a ship: pass astern unless you are certain of a very wide margin.
• Forgetting that motor-sailing makes you a power-driven vessel: day shape and steaming light, and you lose sailing vessel privileges.
• Assuming a big ship will give way to sail: in a TSS or narrow channel she will not, and you must not impede her.
• No radar echo means no vessel: small wooden or GRP craft give poor echoes.
• Altering to port in fog for a vessel forward of the beam.
• Hesitation: decide early — the closing speed of a ship and a yacht leaves little time.

Summary

• Rule 2: ordinary seamanship and the duty to avoid collision always apply; there is no "right of way".
• Keep a proper lookout (5), proceed at safe speed (6), use steady compass bearings to judge risk (7), act early and boldly (8).
• Overtaking vessel always keeps clear (13); head-on, both power vessels alter to starboard (14); crossing, the vessel with the other on her starboard side gives way (15).
• Sailing vessels: port tack gives way to starboard; windward gives way to leeward (12).
• Order of responsibility: NUC and RAM, then CBD (do not impede), fishing, sailing, power.
• In fog there is no stand-on vessel: avoid altering to port for vessels forward of the beam; slow down for fog signals ahead.
• Learn the common lights, shapes and sound signals until recognition is instant.

Check Your Understanding

1. You see a vessel's bearing remain constant while the range decreases. What does this mean?

Answer: Risk of collision exists (Rule 7). Action is required by whichever vessel the Rules make give-way — and by both if necessary.

1. Two yachts are close-hauled: yours on port tack, the other on starboard. Who gives way?

Answer: You do — the vessel on port tack keeps out of the way of the vessel on starboard tack (Rule 12).

1. You are sailing and overtaking a slow motor cruiser. Who gives way?

Answer: You do. An overtaking vessel always keeps out of the way (Rule 13), regardless of type.

1. At night you see a white light above a red light, both all-round, with a green sidelight. What is it, and which way is it going?

Answer: A pilot vessel on duty, underway, showing her starboard side — she is crossing from your left to your right.

1. You see red over red all-round lights and no sidelights. What is it?

Answer: A vessel not under command, not making way through the water.

1. What is the fog signal of a sailing vessel, and how often is it given?

Answer: One prolonged followed by two short blasts, at intervals of not more than 2 minutes.

1. In fog, a radar target is detected fine on your port bow, closing with a steady bearing. Which way should you alter?

Answer: To starboard (or slow down/stop). Rule 19 says avoid altering to port for a vessel forward of the beam.

1. You are the stand-on vessel and the give-way vessel is not altering. What do you do?

Answer: Sound at least five short and rapid blasts; if she still does not act, take action to avoid collision yourself (not altering to port for a vessel on your port side, if power-driven and crossing); and if collision cannot be avoided by her action alone, take the best action to avoid it.

1. You are motoring with sails up. What day shape and lights should you show?

Answer: A cone, point down, forward by day; at night the lights of a power-driven vessel (masthead/steaming light, sidelights and sternlight), not a tricolour.

1. What does five or more short and rapid blasts mean?

Answer: "I do not understand your intentions" or "I doubt that you are taking sufficient action to avoid collision".

1. A sailing vessel on starboard tack is crossing the bows of a power-driven vessel that has her on the port side. Who is the stand-on vessel and what must she do?

Answer: The sailing vessel is the stand-on vessel: Rule 18 requires the power-driven vessel to keep out of her way. She must keep her course and speed (Rule 17), but may take avoiding action alone when it becomes clear the give-way vessel is not acting, and must do so when collision cannot be avoided by the give-way vessel's action alone.

1. How should you cross a traffic separation scheme?

Answer: Cross as nearly as practicable at right angles to the general direction of traffic, with your heading (not necessarily your track) at 90 degrees to the lanes, and avoid unnecessary crossing and crossing where lanes converge.