COLREGs quiz: 139 flashcards with spaced repetition

The one that has the other on her own starboard side. She turns to starboard and passes astern: crossing ahead is not allowed.

Rule 15.

Red means you see her port side, she is crossing right to left ahead of you. You give way: reduce speed and/or turn to starboard.

Rule 15. Mnemonic: red means stop, green means go.

You see her starboard side, so she gives way. Keep your course and speed, but watch her: if she does nothing, act yourself. If she shows no masthead light she is a sailing vessel, and then you keep out of her way.

Rule 15 and 17.

Both to starboard, passing port to port. Not one of them, each.

Rule 14 (a).

Her lights are ahead or nearly ahead, and you see her masthead lights in a line and/or both sidelights. By day, the corresponding aspect.

Rule 14 (b). In doubt, assume it exists.

The overtaking vessel keeps out of the way and stays bound until the other is finally past and clear.

Rule 13. It overrides the crossing rules.

From more than 22.5 degrees abaft her beam: at night you see only her sternlight and neither sidelight.

Rule 13 (b).

Assume it is overtaking and keep out of the way.

Rule 13 (c). Doubt is always resolved on the side of caution.

Not under command, restricted in ability to manoeuvre, constrained by her draught, engaged in fishing, sailing, power-driven. The third step is the odd one: everyone except the first two only has to avoid impeding a vessel constrained by her draught, not to give way to her. Mnemonic: New Reels Catch Fish So Purchase Some.

Rule 18, with 18 (d). Mnemonic: cannot, cannot because of her work, deep draught, fisher, sail, power.

The one on the port tack (wind on her port side).

Rule 12 (a) (i).

The vessel to windward keeps clear of the vessel to leeward.

Rule 12 (a) (ii).

You keep out of her way.

Rule 12 (a) (iii).

Keep her course and speed. But once it is apparent the other is not giving way she may manoeuvre, and when collision cannot be avoided by the other's action alone she shall.

Rule 17 (a), (b).

To port, if the other vessel is on your own port side.

Rule 17 (c).

Early and substantially, so as to keep well clear: one large, obvious manoeuvre rather than a string of small ones.

Rule 16 and 8 (b).

Rules 9, 10 and 13 win. In a channel and a traffic lane a sailing or fishing vessel must not impede a big ship, and the overtaking vessel always keeps clear.

The opening words of rule 18.

Both keep well clear of all vessels and avoid impeding their navigation. On the water the WIG craft is an ordinary power-driven vessel.

Rule 18 (e), (f).

Treat it as existing and act. The sign: the compass bearing of the approaching vessel does not appreciably change.

Rule 7 (a), (d).

Large enough to be readily apparent by eye or on radar. A succession of small alterations is forbidden.

Rule 8 (b).

Taking early action to leave enough sea room for her safe passage. The duty does not lapse when risk of collision develops.

Rule 8 (f).

A vessel restricted in her ability to manoeuvre: all-round red, white, red. With way on she also shows masthead lights, sidelights and a sternlight. Everyone gives way to her except a vessel not under command.

Rule 27 (b).

A vessel not under command making way through the water: two all-round reds, sidelights and a sternlight. No masthead lights, which is the key difference from a vessel restricted in ability to manoeuvre.

Rule 27 (a).

A vessel not under command with no way on: just two all-round reds. Two balls by day.

Rule 27 (a).

A vessel constrained by her draught: three all-round reds together with the lights of a power-driven vessel. A cylinder by day.

Rule 28.

A vessel engaged in trawling: all-round green over white. She is making way, hence the sidelights and sternlight.

Rule 26 (b).

A vessel fishing other than trawling: all-round red over white, nets or lines.

Rule 26 (c).

A fishing vessel with gear extending more than 150 m: red over white plus an all-round white towards the gear. Pass on the opposite side.

Rule 26 (c) (ii).

A pilot vessel on pilotage duty: all-round white over red. Mnemonic: white over red, pilot ahead.

Rule 29 (a).

A vessel engaged in mine clearance: three all-round greens (one at the foremast head, two at the yardarm ends). Do not approach within 1000 m.

Rule 27 (f).

A vessel at anchor of 50 m or more: an all-round white forward and a second, lower, at the stern. No sidelights and no sternlight.

Rule 30 (a).

A vessel aground: anchor lights plus two all-round reds. Three balls by day.

Rule 30 (d).

A towing vessel with a tow up to 200 m: two masthead lights in a vertical line and a yellow towing light above the sternlight. There is an object on a wire astern of her, never pass between.

Rule 24 (a).

A towing vessel with a tow longer than 200 m: three masthead lights in a vertical line, a diamond by day.

Rule 24 (a) (i).

A vessel pushing ahead or towing alongside: two masthead lights, sidelights and a sternlight, but no yellow towing light.

Rule 24 (c).

A vessel being towed: sidelights and a sternlight with no masthead lights. Look ahead of her for the tug with two whites in a column.

Rule 24 (e).

A sailing vessel underway: sidelights and a sternlight only, no masthead light.

Rule 25 (a).

A sailing vessel with the optional lights: all-round red over green at the masthead. Do not confuse with white over red (pilot) or red over white (fishing).

Rule 25 (c).

A vessel under sail with her engine running: the lights of a power-driven vessel, and a cone point down by day.

Rule 25 (e).

A power-driven vessel under 12 m: an all-round white instead of masthead and sternlight, plus sidelights.

Rule 23 (d) (i).

A power-driven vessel of 50 m or more: two masthead lights in line (the after one higher), sidelights, sternlight.

Rule 23 (a).

An air-cushion vessel in non-displacement mode: the normal set plus an all-round flashing yellow.

Rule 23 (b).

A WIG craft taking off, landing or in flight near the surface: the normal set plus a high-intensity all-round flashing red.

Rule 23 (c).

A dredger with an obstruction: red, white, red plus two reds on the obstructed side and two greens on the side you may pass. Go where the greens are.

Rule 27 (d).

A vessel restricted in ability to manoeuvre at anchor: red, white, red plus the anchor lights.

Rule 27 (b) (iv).

A vessel at anchor under 50 m: a single all-round white where it can best be seen.

Rule 30 (b).

Towing that severely restricts the ability to deviate: the towing lights plus red, white, red.

Rule 27 (c).

You see the white sternlight (135 degrees) and any all-round lights. You cannot see the masthead lights (225 degrees forward) or the sidelights (112.5 degrees forward).

Rule 21.

Assume you are overtaking and keep out of the way until you are sure you are not. A white with no colours is usually the sternlight of a vessel ahead: you see no sidelights, so you are in her stern sector. A vessel at anchor and a small craft with an all-round white look the same, and closing on them is still your job.

Rule 13 (c): if in doubt, assume you are overtaking. Also rules 21, 23 (d), 30.

Masthead 225 degrees, sidelights 112.5 each, sternlight 135, all-round 360.

Rule 21. 225 plus 135 makes 360.

A towing light: she is towing on a wire.

Rule 21 (d) and 24 (a) (iv).

Lights from sunset to sunrise, and by day in restricted visibility or whenever necessary. Shapes by day.

Rule 20.

Sidelights and a sternlight are added. Masthead lights are not, unlike a vessel restricted in ability to manoeuvre.

Rule 27 (a) (iii) versus 27 (b) (iii).

No. A vessel engaged in fishing shows only the rule 26 lights, underway or at anchor. A vessel not fishing must not show them at all.

Rule 26 (a), (e).

White over red is a pilot, red over white is fishing other than trawling. The order changes the meaning completely. Mnemonic: white over red, pilot ahead; red over white, fishing at night.

Rule 29 (a) and 26 (c).

Green over white: trawling, she is dragging gear. Red over white: any other kind of fishing.

Rule 26 (b), (c).

A sailing vessel underway: she carries no masthead light, only sidelights and a sternlight. You see her starboard side, so she crosses from left to right. If you are power-driven, you keep out of her way (rule 18 (a) (iv)); if you are under sail too, rule 12 decides by tack and by windward, not by which side she is on.

Rule 25 (a), with 18 (a) (iv) and 12.

She is a power-driven vessel of 50 metres or more: the second masthead light is compulsory from that length, and it sits higher and abaft the first. The height difference shows which way her bow points.

Rule 23 (a).

A vessel engaged in fishing: trawling or any other fishing.

Rule 26 (b) (i), (c) (i).

A vessel restricted in her ability to manoeuvre: the daytime equivalent of red, white, red.

Rule 27 (b) (ii).

A vessel not under command: the daytime equivalent of two all-round reds.

Rule 27 (a) (ii).

A vessel constrained by her draught: the daytime equivalent of three all-round reds.

Rule 28.

A vessel aground.

Rule 30 (d) (ii).

A vessel at anchor.

Rule 30 (a) (i).

She is under sail and using her engine, so by the rules she is a power-driven vessel.

Rule 25 (e).

Her gear extends more than 150 metres in that direction.

Rule 26 (c) (ii).

The length of tow exceeds 200 metres. Both the towing and the towed vessel show it.

Rule 24 (a) (v), (e) (iii).

Diving operations from a vessel that cannot show the full set of lights and shapes.

Rule 27 (e) (ii).

The balls mark the side with the obstruction. The diamonds mark the side you may pass.

Rule 27 (d).

A mine clearance vessel (balls at the foremast head and yardarm ends): do not come within 1000 m. Three balls in a vertical line would mean aground.

Rule 27 (f) and 30 (d).

“I am altering my course to starboard”.

Rule 34 (a).

“I am altering my course to port”.

Rule 34 (a).

“I am operating astern propulsion”.

Rule 34 (a).

“I do not understand your intentions” or “I doubt whether you are taking sufficient action”. Sounded immediately, and may be joined by flashes.

Rule 34 (d). It is not a distress signal.

In a narrow channel or fairway only: “I intend to overtake you on your starboard side”. Two prolonged and two short means on your port side.

Rule 34 (c) (i).

The vessel being overtaken in a channel: “agreed, come through”, and she then takes steps to permit safe passing.

Rule 34 (c) (ii) and 9 (e) (i).

A power-driven vessel making way through the water.

Rule 35 (a).

A power-driven vessel underway but stopped, with no way on.

Rule 35 (b).

Not under command, restricted in ability to manoeuvre, constrained by draught, sailing, fishing, towing or pushing.

Rule 35 (c).

A vessel towed, or the last vessel of the tow, when manned.

Rule 35 (e).

At anchor, rapid ringing of the bell for about 5 seconds every minute (from 100 m, bell forward and gong aft). Aground, the same plus three separate strokes before and after.

Rule 35 (g), (h).

One prolonged blast. Any vessel round the bend within hearing must answer with one prolonged blast.

Rule 9 (f) and 34 (e).

Short about 1 second, prolonged 4 to 6 seconds.

Rule 32 (b), (c).

From 12 m a whistle, from 20 m also a bell, from 100 m also a gong. Under 12 m, any means of making an efficient sound signal.

Rule 33.

Continuous sounding of any fog-signalling apparatus. Plus the Annex IV signals: red parachute flare, orange smoke, SOS, “Mayday”, flags N and C.

Rule 37.

A pilot vessel engaged on pilotage duty, as an identity signal.

Rule 35 (k).

Not at anchor, not made fast to the shore, not aground. A vessel drifting with her engine stopped is underway too.

Rule 3 (i).

Only when one can be observed visually from the other. A radar contact is not in sight, and rules 11 to 18 then do not apply.

Rule 3 (k).

The first cannot manoeuvre through exceptional circumstance (breakdown). The second cannot because of the nature of her work: cable, dredging, replenishment underway, aircraft operations, mine clearance, a heavy tow.

Rule 3 (f), (g).

A power-driven vessel only, whose draught in relation to the available depth and width of navigable water severely restricts her ability to deviate from her course.

Rule 3 (h).

Fishing with trolling lines or other apparatus that does not restrict manoeuvrability.

Rule 3 (d).

Fog, mist, falling snow, heavy rainstorms, sandstorms and any similar cause.

Rule 3 (l).

When it is necessary to avoid immediate danger. At the same time they do not exonerate anyone who neglected the ordinary practice of seamen.

Rule 2 (a), (b).

A yellow light with the same characteristics as a sternlight (135 degrees), shown above the sternlight of a towing vessel.

Rule 21 (d).

A light flashing at regular intervals at a frequency of 120 flashes or more per minute.

Rule 21 (f).

A pushing vessel and a vessel pushed ahead rigidly connected. They show the ordinary lights of a power-driven vessel under rule 23.

Rule 24 (b).

The strip between the coast and a traffic separation scheme. It is used by vessels under 20 m, sailing vessels, vessels engaged in fishing, and any vessel going to or from a port, installation or pilot station inside the zone.

Rule 10 (d).

A multimodal craft that in her main operating mode flies close to the surface using surface-effect action. Taking off, landing and in flight she keeps well clear of all vessels; on the water she is a power-driven vessel.

Rule 3 (m) and 18 (f).

The speed at which you can stop within the distance that matters in those conditions. It is set by visibility, traffic density, manoeuvrability, background lights and shore, wind and sea, and draught against the depth.

Rule 6.

The bearing of the other vessel does not change while the range decreases. With a very large vessel, with a tow and at close range risk can exist on a changing bearing too, and scanty information counts as risk by itself.

Rule 7 (d).

Early, large and readily apparent to the other vessel, visually and by radar. A string of small alterations is forbidden, you pass at a safe distance and keep checking until finally past and clear.

Rule 8.

It is the limit abaft the beam where the sidelights and masthead light stop. Beyond it only the sternlight shows, and that is the overtaking zone.

Rule 21 (a), (b) and 13 (b).

Masthead 6 miles; sidelights, sternlight, towing light and all-round lights 3 miles.

Rule 22 (a).

Masthead 5 miles (3 miles if under 20 m), the rest 2 miles.

Rule 22 (b).

Masthead 2 miles, sidelights 1 mile, sternlight, towing light and all-round lights 2 miles.

Rule 22 (c).

200 metres, measured from the stern of the towing vessel to the after end of the tow: three masthead lights instead of two, plus a diamond shape.

Rule 24 (a).

When the gear extends more than 150 metres horizontally: an all-round white or a cone point up towards it.

Rule 26 (c) (ii).

Within 1000 metres.

Rule 27 (f).

Second masthead light from 50 m. Deck lighting at anchor is required for vessels of 100 m and more.

Rule 23 (a) (ii) and 30 (c).

On the whistle, not more than every 2 minutes. The anchor bell, not more than every minute, ringing for about 5 seconds.

Rule 35.

Under 12 m: exempt from rule 27, except diving operations. Under 12 m aground: exempt from the two reds and three balls. Under 7 m at anchor away from channels: exempt from the anchor light.

Rule 27 (g), 30 (e), (f).

A flashing light, 120 or more per minute. A manoeuvring flash about 1 second, about 1 second between flashes, not less than 10 seconds between signals.

Rule 21 (f) and 34 (b).

From 25 metres in breadth, two more all-round whites at the sides. Over 100 metres in length, lights spaced so the gap never exceeds 100 metres.

Rule 24 (g).

Masthead 225, each sidelight 112.5, sternlight 135, all-round 360. The sidelights plus the sternlight make a full circle.

Rule 21.

A power-driven vessel of less than 7 metres whose speed does not exceed 7 knots may show one all-round white, and sidelights if practicable.

Rule 23 (d).

An alteration to port for a vessel forward of the beam (other than one being overtaken). Also altering towards a vessel abeam or abaft the beam.

Rule 19 (d).

Reduce speed to the minimum at which you can be kept on course, take all your way off if necessary, and navigate with extreme caution until the danger is over.

Rule 19 (e).

A power-driven vessel keeps her engines ready for immediate manoeuvre and her speed safe for the conditions.

Rule 19 (b).

The outer limit that lies on your starboard side, as near to it as is safe and practicable.

Rule 9 (a).

A vessel under 20 m, a sailing vessel and a vessel engaged in fishing. A fishing vessel must not impede any vessel in the fairway.

Rule 9 (b), (c).

Only by agreement: the overtaking vessel signals her intention, the other agrees and takes steps to permit safe passing. The agreement does not release her from rule 13.

Rule 9 (e).

On a heading as nearly as practicable at right angles to the general direction of flow, and ideally not crossing at all.

Rule 10 (c).

In a narrow channel (if it can be avoided) and in a traffic separation scheme or near its ends.

Rule 9 (g) and 10 (g).

At the ends of the lane. From either side, at as small an angle as practicable to the direction of flow.

Rule 10 (b) (iii).

Sound at least five short and rapid blasts: the doubt signal of rule 34 (d).

Rule 9 (d) and 34 (d).

Nobody stands on: the rules about who gives way do not apply in fog, the duties are mutual. Safe speed, engines ready, take avoiding action in ample time.

Rule 19.

To port. In region A a red can marks the port side of the channel along the direction of buoyage, a green cone the starboard side.

IALA system, region A.

A north cardinal mark: pass it to the north, the danger lies to the south of it. The light is white and continuous quick or very quick (Q or VQ).

IALA cardinal marks.

A west cardinal mark: pass it to the west, the danger lies to the east. The light is Q(9) 15s, nine flashes like 9 o'clock on the clock face.

IALA cardinal marks.

An isolated danger: a shoal or a rock right under the buoy with clear water all round it. Pass either side, but not close. The light is Fl(2) white.

IALA isolated danger mark.

A safe water mark (mid-channel): it marks the axis of a channel or a landfall, and the water under it is deep. The light is Iso, Oc, LFl 10s or Morse A.

IALA safe water mark.

An emergency wreck mark: a fresh danger that is not on the chart yet, most often a wreck. The light alternates blue and yellow.

IALA emergency wreck mark.

1852 metres, the length of one minute of latitude. A knot is one nautical mile per hour. Take distance from the side scale of the chart at your own latitude.

Mercator chart, units of distance.

True = compass + error, where the compass error is variation plus deviation. Westerly values go in with a minus sign. Only true directions go on the chart.

Compass error.

1, 2, 3, 3, 2, 1 twelfths over six hours. Half the range arrives in the two middle hours. Depth = charted depth plus the height of tide.

The rule of twelfths.

At new moon and full moon: sun, earth and moon line up and the forces add. Those are spring tides. At the quarters the tides are smallest, the neaps.

Springs and neaps.

Cold: a short hard downpour with a squall and a temperature drop, cumulonimbus cloud, a belt 50 to 70 km wide. Warm: long drizzle over 300 to 400 km, cirrus then stratus, and it gets warmer.

Weather fronts.

16 for distress, urgency and calling; 70 for digital selective calling, where voice is not allowed. Also 06 for survival craft and 13 for safety of navigation.

VHF channels and GMDSS.

Anticlockwise and inwards, towards the centre of the low. In a high it turns clockwise and outwards. In the southern hemisphere it is all mirrored.

Lows and highs.

Apparent wind is the true wind plus the headwind of the boat's own movement: on a close course it draws forward and feels stronger, downwind it feels weaker. A forecast always gives the true wind.

True and apparent wind.