The Rules are asked here by number and paragraph, for a yacht of 20 m or more, where the small-craft allowances stop: which rule governs, what it asks, and who the other vessel is.
1 · Rules 1–8
Look out, judge, act
How do I know if there is a risk of collision with a ship?
Rule 7: a steady compass bearing, or any doubt, means risk of collision; with a huge ship close, risk can exist even while the bearing moves. Then act under Rule 8: early, with one large, obvious alteration.
Under way (3(i)): not at anchor, made fast or aground, so on a sea anchor you are under way. Not under command (3(f)) needs an exceptional circumstance; dismasted but motoring: power-driven. In sight (3(k)): by eye only.
Rule 5: a look-out by sight and hearing, always. Rule 6: radar's limits count against speed. Rule 7 says when risk exists, Rule 8 how to act; taking way off (8(e)) clears one vessel when a turn would close another. A plot gives her true course, hence the rule. Rule 2 adds seamanship: call her, light your sails.
Risk and action (Rules 7 and 8)
Steady compass bearing, or doubt: risk
After your own turn a relative bearing lies
A minute of radar data is scanty (7(c))
Huge ship close: risk even as bearing moves
Early, one large obvious alteration (8(b))
Hold on until finally past and clear (8(d))
2 · Rules 9 and 10
Channels and lanes
How do I cross a traffic separation scheme in a yacht?
On a heading at right angles to the lane (Rule 10(c)). Rule 10 relieves you of none of the other rules: under 20 m or under sail you also must not impede ships following the lane (10(j)).
Keep to the starboard side of a channel (9(a)). Under 20 m or sailing, do not impede a vessel confined to it (9(b)); at 20 m under power you meet her under Rule 14. Fishing impedes nobody there (9(c)); nobody crosses if that impedes a channel-bound vessel (9(d)). Not to impede means leaving room early; once risk exists both duties stand (8(f)).
Rule 10 at a glance
(b) Follow the lane; join at a small angle (c) Cross on a heading at right angles (d) Inshore zone: <20 m, sail, fishing, or bound for a port inside it (e) Separation zone: emergency, or fishing (g) No anchoring · (h) unused: keep clear
Rule 10 relieves nobody of the other rules (a): at 20 m under power Rules 13 and 15 apply as anywhere; under 20 m or sailing you also must not impede ships following the lane (j). All but NUC and RAM avoid impeding a vessel constrained by her draught (18(d)); a cable ship at work is exempt (l).
3 · Rules 12–18
In sight of one another
When am I overtaking a ship rather than crossing her, under Rule 13?
When you come up from more than 22.5° abaft her beam, where only her sternlight shows. Overtaking overrides the other rules, whatever she is: keep clear until past and clear, even if the bearing later changes.
Overtaking (13): from more than 22.5° abaft her beam, where only her sternlight shows. It overrides the rest, whatever she is: keep clear until past and clear; a later bearing change changes nothing. Head-on (14): both to starboard, boldly; in doubt assume it. Crossing (15): the one with the other on her starboard side keeps clear. Port tack, a windward yacht's tack unknown: keep clear (12(a)(iii)).
Rule 17: the stand-on vessel
(a)(i) Keep your course and speed (a)(ii) May act once she plainly does not (b) Must act when she alone cannot avoid it (c) Power: no turn to port for one to port
A VHF agreement overrides none of this
Rule 18: power yields to sail, both to fishing, all to RAM and NUC. A warship recovering aircraft is RAM; a pilot vessel plain power. Seaplanes and WIG craft keep clear of all; a seaplane on the water follows the steering rules once risk exists.
Pilot vessel
Sail, red over green
Hovercraft
WIG craft
4 · Rule 19 and fog signals
When you cannot see her
Which way should I turn in fog for a ship on radar ahead?
Avoid a turn to port for a vessel forward of the beam, unless you are overtaking her, and a turn towards one abeam or abaft it: Rule 19(d). Act in ample time; ten degrees barely moves the CPA.
Rule 19 governs vessels not in sight of one another in or near restricted visibility, radar and VHF contact or not. Act in ample time, avoiding a turn to port for a vessel forward of the beam, unless overtaking her, and a turn towards one abeam or abaft it (19(d)). If neither is open, or a fog signal sounds forward of the beam, slow to bare steerage way or stop (19(e)). Ten degrees barely moves the CPA.
Fog signals (Rule 35)
Power, making way: 1 prolonged, every 2 min
Power, under way, stopped: 2 prolonged
NUC/RAM/sail/fishing/tow: 1 long, 2 short
At anchor: bell 5 s/min; 100 m+: gong aft
Aground: 3 strokes, the bell, 3 strokes
A pushing unit sounds as one. From 20 m you carry and ring a bell; at anchor add short, prolonged, short to warn a vessel standing into you.
5 · Rules 21–25, Annex I
Arcs, ranges, heights
Can a sailing yacht of 20 m or more still show a tricolour masthead light?
No: from 20 m a sailing vessel loses the tricolour (Rule 25(b)). She shows separate sidelights and a sternlight, optionally red over green at the masthead, never with the engine driving.
Masthead light 225°, each sidelight 112.5°, sternlight and yellow towing light the other 135°: her lights fix her aspect. Masthead lights and red: you are forward of her port beam; yellow over white: in her stern arc.
From 20 m a sailing yacht loses the tricolour (25(b)): separate sidelights and sternlight, red over green optional at the masthead, never with the engine driving; seen with a steaming light, assume the worse. Under sail, no masthead light: a ship sees her at two miles. Under 50 m a second masthead light is optional.
Rule 22 and Annex I, from 20 m
Masthead 5 M (3 M under 20 m); the rest 2 M
Masthead ≥ 6 m up, or her breadth if more
Sidelights no higher than ¾ of it
Vertical line: 2 m apart, the lowest 4 m up
2nd masthead: 4.5 m higher, half length aft
Manoeuvring light: 5 M, 2 m from masthead
6 · Rules 24–30, Annex II
At work, in trouble
What lights does a vessel not under command show at night?
Not under command (Rule 27(a)): two red lights, by day two balls. She adds sidelights and a sternlight only when making way through the water, not while drifting.
Towing (24): two masthead lights in a line, three when the tow, tug's stern to its end, exceeds 200 m (a diamond by day); yellow towing light over the sternlight, so from astern the length is hidden. A rigid pushing unit is one power vessel. Towing your tender, you show them; 24(i) relieves only a tow in distress. A long, low tow: whites at each end and every 100 m.
NUC making way, astern
Dredger: pass the greens
Tug, restricted
Trawler hauling
Purse seiner
Aground
NUC (27(a)): two reds, two balls; sidelights and sternlight only when making way through the water, not drifting. RAM: red, white, red; ball, diamond, ball; at anchor plus anchor light. A dredger: two reds on the blocked side, two greens to pass; at anchor these replace anchor lights. A small dive boat: red, white, red, or a rigid flag A, 1 m. Three greens or balls in a triangle: mine clearance. Aground: anchor light and two reds; three balls.
Annex II: trawlers working together
Shooting nets: two whites below
Hauling: white over red
Net fast on an obstruction: two reds
Pair trawlers (searchlights): never between
Purse seiner hampered: two yellows flashing
7 · Rules 33–36, Annexes III–IV
Sound, light, distress
What do one, two and three short blasts from a ship mean?
They are manoeuvring signals (Rule 34(a)) from a power-driven vessel in sight of another: one short blast, altering to starboard; two, to port; three, engines astern. A yacht under sail makes none.
Manoeuvring signals (34(a)) belong to a power-driven vessel under way, in sight of another: one short blast, to starboard; two, to port; three, engines astern. Under sail, none. A light may repeat them (34(b)): an all-round white seen at 5 M, 2 m from the masthead light, one flash per blast.
Annex III, from 20 m: a whistle of 250–700 Hz heard at 1 M (a 200 m ship: 2 M), a bell with a 300 mm mouth. To attract attention (36): any signal not mistakable for another, a searchlight on your sails, never her bridge. Annex IV lists the distress signals; any use except in distress is forbidden.
Annex IV: distress
A gun or explosion about once a minute
A fog signal sounded continuously; SOS
Flames aboard; red flares; orange smoke
Square flag + ball; arms slowly up and down
MAYDAY, DSC, EPIRB · not an inverted ensign
Orange sheet (square, circle): for aircraft
Practice questions
Questions from this topic, as the app asks them. Open one to see the answer.
Night, 120 M offshore, under sail
You: 22 m sloop, the stand-on vessel
Ship 40° on your port bow, 4 M
Bearing steady, no sign of altering
Your watch leader says Rule 17 leaves you nothing to do but hold on. What does Rule 2 add?
Precautions too — call her, light up your sails
Fire a red flare so that she cannot miss you
Nothing — holding on is all a stand-on vessel does
Turn to port now and cross well ahead of her
Show the answer
A. Precautions too — call her, light up your sails
Rule 2(a): no rule excuses neglect of good seamanship — a VHF call, a light on the sails (Rule 36); a red flare means distress.
All 100 questions of this topic are in the app: practice by topic with the reason after every answer, your mistakes brought back, and a timed mock exam. Free, no sign-up, in the browser or in Telegram.
