Lights, Shapes and Fog Signals

Prerequisites

• You have studied the lesson Collision Regulations for the ICC and know the vessel types in Rule 18: not under command, restricted in ability to manoeuvre, constrained by draught, fishing, sailing and power-driven.
• You know port (red) from starboard (green) and can recognise the bow and stern of a vessel.
• This lesson covers the coastal waters knowledge part of the ICC. The assessor restricts questions on your own lights to your own type of boat, but expects you to recognise at least four types of other vessel from their lights.

Learning Objectives

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

• State the lights and shapes your own boat must show under sail, under engine and at anchor (ICC coastal collision regulations 2, COLREGs Rules 20 to 25 and 30).
• Recognise from their lights a power-driven vessel, a sailing vessel, a vessel at anchor, a tug and tow and a dredger, and say which aspect you are seeing (coastal collision regulations 3).
• Recognise the lights and day shapes of vessels not under command, restricted in ability to manoeuvre, constrained by draught, fishing, pilot vessels and vessels aground.
• Give the fog signals made by a power-driven vessel, a sailing vessel, a vessel at anchor, a tug and tow and a dredger, and the one for your own boat (coastal collision regulations 4, Rule 35).

Light Basics

When lights and shapes are shown

Lights are shown from sunset to sunrise and in restricted visibility by day. Shapes are shown by day. Between sunset and sunrise you must not show other lights that could be mistaken for navigation lights or that spoil the lookout, which includes a bright cockpit or deck light left on while under way.

The four basic lights

A towing light is yellow, with the same arc as a sternlight, and goes above the sternlight. Notice that the masthead light and sidelights together cover exactly the sector the sternlight does not. From any angle you see either the forward lights or the sternlight, never both. This is what lets you read a vessel's aspect.

Ranges for small vessels

A yacht's sidelights are only required to be visible at 1 or 2 miles. A ship at 20 knots covers a mile in three minutes, which is why you show your lights early and keep a radar reflector rigged.

Your Own Boat's Lights

The assessor's question "What lights should you show on your own boat at night?" is limited to your type of boat. Know your answer cold.

Sailing vessel under way (Rule 25)

• Sidelights and a sternlight. On a yacht these are usually a bicolour lantern on the pulpit and a white light on the pushpit.
• Under 20 m, these may instead be combined in one tricolour lantern at or near the masthead. A tricolour is easier to see at a distance and uses little power, which suits a long passage, but it must be switched off the moment the engine goes on.
• A sailing vessel may also show, at the masthead, two all-round lights in a vertical line, red over green, in addition to her sidelights and sternlight. These must not be shown with a tricolour.
• Under 7 m, if she cannot show sidelights and a sternlight, a sailing vessel must have a white torch or lantern ready to show in time to prevent collision. The same applies to a rowing boat.

Under engine or motor-sailing (Rule 23)

With the engine running and in gear, your yacht is a power-driven vessel. Show:

• a white masthead light (on a yacht, the "steaming light" fixed to the front of the mast, partway up);
• sidelights (the bicolour on the pulpit);
• a sternlight.

Not the tricolour: it would show your sternlight and sidelights at the masthead and confuse everyone. A power-driven vessel under 12 m may instead show one all-round white light plus sidelights; under 7 m with a top speed of 7 knots or less, one all-round white light alone (and sidelights if practicable). Most motor cruisers show the standard set: masthead, sidelights, sternlight.

By day, motor-sailing, a sailing yacht with sails up and engine running shows a cone, point down, in the forepart of the boat (Rule 25(e)). Few do, but the assessor may ask.

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At anchor (Rule 30)

• One all-round white light where it can best be seen, for a vessel under 50 m. Ships of 50 m or more show two: one forward and a lower one aft. Ships of 100 m or more also light up their decks.
• By day, one black ball in the forepart, usually hoisted on the forestay.
• A vessel under 7 m, anchored away from channels, fairways, anchorages and where others normally navigate, need not show the light or the ball.

In a crowded Mediterranean anchorage a masthead anchor light can be hard to see from a dinghy at water level. Many skippers add a second white light low in the cockpit, which is allowed as long as it reads as an all-round white anchor light.

Charter handover check

On an unfamiliar boat, find out which switch is which before dark. Panels are often labelled "nav", "steaming", "anchor" and "tricolour", sometimes in the local language. Test each with someone on the pontoon looking at the boat, and check you can see the correct lights from ahead, abeam and astern.

The diagram below shows the arcs of a sailing vessel's sidelights and sternlight seen from above.

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Recognising Other Vessels at Night

A method that works

1. Colours and count. How many lights, and which colours? Look for red over red, red-white-red, green over white, white over red.
2. Arrangement. Vertical lines of all-round lights tell you the vessel's status. Lights spread horizontally tell you her length and heading.
3. Aspect. Which sidelight can you see? Both, one, or only a white sternlight?
4. Bearing over time. Take bearings to see whether she is a threat. Never decide from a single glance.

Power-driven vessel under way (Rule 23)

• Under 50 m: one masthead light, sidelights, sternlight.
• 50 m or more: two masthead lights, the aft one higher than the forward one. A smaller vessel may show the second light too.
• Hovercraft in non-displacement mode add a yellow all-round flashing light.

Two masthead lights act like a pointer. If the lower (forward) light is to the left of the higher one, the ship is heading left. If they are in line, one above the other, she is heading straight at you or straight away (then you would see her sternlight instead).

Sailing vessel under way (Rule 25)

Sidelights and sternlight only, with no masthead light. A tricolour high up, or red over green all-round at the masthead, also means a sailing vessel. At sea, a lone red or green light low down with no white light above it is very likely a yacht under sail.

Vessel at anchor (Rule 30)

One all-round white light (under 50 m) or two (50 m or more, forward one higher). No sidelights. A big ship at anchor is often lit up like a block of flats by her deck lights. Because an anchor light and a sternlight are both white, take bearings: an anchored vessel's bearing changes only because you are moving.

Tug and tow (Rule 24)

A power-driven vessel towing astern shows:

• two masthead lights in a vertical line instead of one, or three if the length of the tow, from the tug's stern to the back of the tow, is more than 200 m;
• sidelights and a sternlight;
• a yellow towing light above the sternlight.

The vessel being towed shows sidelights and a sternlight, with no masthead light. If the tow is over 200 m, both tug and tow show a diamond shape by day.

A vessel pushing ahead or towing alongside shows two masthead lights in a vertical line, sidelights and sternlight, but no towing light. The pushed or towed vessel shows sidelights and, if towed alongside, a sternlight.

Never pass between a tug and her tow. The towline may be a few metres under water, and the tow may be hundreds of metres astern, unlit by modern standards. From astern, yellow over white means a tow is somewhere ahead of you.

Dredger and underwater operations (Rule 27)

A dredger at work is restricted in her ability to manoeuvre. She shows:

• red, white, red all-round lights in a vertical line (the RAM signal);
• two all-round red lights in a vertical line on the side where the obstruction (her pipe or wires) lies;
• two all-round green lights in a vertical line on the side where another vessel may pass;
• when making way, masthead light, sidelights and sternlight as well. At anchor, she shows these lights instead of anchor lights.

By day the same vessel shows ball, diamond, ball, with two balls on the obstructed side and two diamonds on the side where you may pass. Remember: pass on the green or diamond side.

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Other vessels you should know

Memory aids: "red over red, the captain is dead" (NUC), "red over white, fishing at night", "green over white, trawling tonight", "white over red, pilot ahead". A vessel not under command that is not making way shows only red over red, so its two reds and no sidelights tell you she is stopped and helpless.

Vessels under 12 m are excused the NUC and (except when diving) RAM lights, and vessels under 12 m aground need not show the aground signal.

The panel below shows the main configurations as they appear at night.

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Reading Aspect

The assessor will ask "What type of vessel is this, and what aspect is shown?" Aspect is the angle from which you are seeing her, and it tells you which way she is heading.

With a ship showing two masthead lights, the spread tells you more. Lights wide apart: you see her broadside. Lights closing up into a vertical line: she is turning towards you. If the lights open out again, she has turned away.

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Worked example. At night off Cherbourg you see two white lights, the left one lower, and a red light below and to the right of them. Lower forward light on the left, so she heads left. Red, so you see her port side. Two masthead lights: she is 50 m or more. A power-driven ship over 50 m crossing from your right to your left. If you are motoring she is on your starboard side, so you give way (Rule 15). If you are under sail she should keep clear of you, but watch her bearing closely and act early if she does not.

Day Shapes

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A small diving boat often cannot show the RAM shapes. Instead she shows a rigid replica of the International Code flag A (white and blue swallowtail): keep well clear and slow down.

Fog Signals (Rule 35)

In or near restricted visibility, by day or night, vessels sound fog signals. A prolonged blast lasts 4 to 6 seconds, a short blast about 1 second.

A vessel at anchor may also sound one short, one prolonged, one short to warn an approaching vessel. A dredger working at anchor, and a fishing vessel at anchor, sound one prolonged and two short instead of the bell.

Your own boat in fog

The assessor's question "What sound signal would you make in your own vessel in fog?" has a simple answer:

• Under sail: one prolonged and two short blasts, at intervals of not more than two minutes.
• Under engine, including motor-sailing: one prolonged blast every two minutes (two prolonged if you stop and lie still in the water).
• At anchor: ring the bell rapidly for about five seconds every minute.

A vessel under 12 m is not obliged to give these exact signals, but must make some other efficient sound signal at least every two minutes. In practice, use the proper signal on an aerosol or electric horn.

"What does one long and two short mean?"

This is the assessor's other sample question, and the point is that it covers several vessels. One prolonged and two short means a vessel that cannot easily keep out of your way: a sailing vessel, a vessel not under command, restricted in her ability to manoeuvre (such as a dredger), constrained by her draught, engaged in fishing, or towing or pushing. You cannot tell which from the sound alone, so treat it with caution.

What else to do in fog

Signals are only part of the job. When fog comes in:

• fix your position and note it in the log;
• switch on navigation lights;
• hoist a radar reflector if it is not permanently fitted, and switch on AIS and radar if fitted;
• put lifejackets on everyone, and have the liferaft and grab bag ready;
• post a lookout forward, away from engine noise, to listen as well as look;
• slow to a safe speed and have the engine running ready for use, even under sail;
• consider heading for shallow water outside the shipping lanes, where big ships cannot go, and anchoring until it clears.

On hearing a fog signal apparently forward of the beam, slow to bare steerage way and stop if necessary until you know where the other vessel is (Rule 19).

Worked Example: A Night Crossing to the Channel Islands

You are motor-sailing at 5 knots from Poole towards Alderney at 0200, showing steaming light, sidelights and sternlight. You see:

1. A single white light, slowly brightening, bearing steady. Anchor light or sternlight? Out in mid-Channel no one anchors, so it is probably a vessel ahead going the same way, and you are overtaking. You keep clear (Rule 13).
2. Green over white, with a red sidelight below and a white light above and behind. A trawler, showing her port side, with her optional masthead light. She is making way. You are power-driven, so you keep clear of a vessel engaged in fishing (Rule 18), passing well astern of her.
3. Three white lights in a vertical line above a green, with a yellow light seen later from astern. A tug towing, tow over 200 m, seen from her starboard side. You look for the tow's green sidelight far behind and pass well astern of the tow, never between.
4. Red over red with no sidelights. A vessel not under command, not making way. You alter well round her.
5. Fog patches arrive. You switch to one prolonged blast every two minutes (you are under engine), slow to 3 knots and post a lookout forward. You hear one prolonged and two short ahead: a sailing vessel or one of the vessels above. You slow to steerage way until you hear it pass.

Common Mistakes

• Tricolour on while motoring. Under engine you must show a masthead light, sidelights and sternlight, and the tricolour must be off.
• Steaming light left on under sail. It turns you into a power-driven vessel in everyone else's eyes.
• Confusing red over white (fishing) with white over red (pilot). Use the rhymes.
• Passing between a tug and tow. Look for two or three white masthead lights in a line and find the tow before you commit.
• Passing on the wrong side of a dredger. Pass on the side with the green lights by night or diamonds by day.
• Identifying from one light. A single white light could be a sternlight, an anchor light or a small boat. Watch it and take bearings.
• Forgetting the fog signal changes when the engine goes on. Sail: long, short, short. Engine: one long.

Summary

• Masthead light 225° white, sidelights 112.5° red and green, sternlight 135° white, towing light yellow above the sternlight. Lights sunset to sunrise and in poor visibility; shapes by day.
• Under sail: sidelights and sternlight, or a tricolour at the masthead if under 20 m. Under engine: masthead light, sidelights, sternlight. At anchor: all-round white; black ball by day. Motor-sailing by day: cone point down.
• Power-driven: masthead light (two if 50 m or more, aft higher), sidelights, sternlight. Sailing: no masthead light. Anchor: all-round white(s).
• Tug: two masthead lights in a line (three if tow over 200 m) and yellow over white aft. Tow: sidelights and sternlight.
• Dredger: red-white-red, two reds on the obstructed side, two greens on the side to pass. By day ball-diamond-ball, two balls and two diamonds.
• NUC red over red; fishing red over white; trawling green over white; pilot white over red; CBD three reds.
• Fog: power making way one prolonged; stopped two prolonged; sail, NUC, RAM, CBD, fishing and towing one prolonged two short; tow one prolonged three short; anchor bell for 5 seconds every minute.

Check Your Understanding

1. What lights does your 11 m yacht show under sail at night, and what changes when you start the engine?

Answer: Under sail: sidelights and sternlight, or a masthead tricolour. Under engine: masthead (steaming) light, sidelights and sternlight, with the tricolour switched off.

1. What do you show at anchor by night and by day?

Answer: One all-round white light where it is best seen at night, and one black ball in the forepart by day.

1. You see two white lights in a vertical line, a green light and, later, a yellow light above a white one. What is it?

Answer: A power-driven vessel towing astern, tow 200 m or less. First you see her starboard side, then her stern with the yellow towing light above the sternlight.

1. A vessel shows red, white, red in a vertical line, with two reds to one side and two greens to the other. What is she, and which side do you pass?

Answer: A dredger (or vessel on underwater operations) restricted in her ability to manoeuvre. Pass on the side of the two green lights.

1. You see a masthead light and a red sidelight. Which aspect, and which way is she going?

Answer: Her port side. She is a power-driven vessel crossing from your right to your left.

1. What does a cylinder hoisted by day mean?

Answer: A vessel constrained by her draught. Do not impede her.

1. What fog signal do you sound under sail? And under engine?

Answer: Under sail one prolonged and two short blasts at intervals of not more than two minutes. Under engine and making way, one prolonged blast at intervals of not more than two minutes.

1. You hear one prolonged and two short blasts in fog. Name three vessels that might be making it.

Answer: Any three of: a sailing vessel, a vessel not under command, restricted in her ability to manoeuvre (such as a dredger), constrained by her draught, engaged in fishing, or towing or pushing.

1. You hear a bell rung rapidly for five seconds, once a minute. What is it?

Answer: A vessel at anchor (under 100 m). Over 100 m she would also sound a gong aft.