The International Regulations for Preventing Collisions at Sea, 1972 — the COLREGs. They apply to every vessel on Australian water, from a kayak to a container ship, and they are the single body of knowledge every skipper assessment tests.
In Australia the COLREGs carry force federally through Marine Order 30 (Prevention of Collisions) 2016, made under the Navigation Act 2012, under which it is an offence for an owner or master to operate a vessel in contravention of them. Each state then applies the same rules to its own waters through its marine safety legislation. So a recreational skipper on Sydney Harbour is answerable to the same rules as a ship in the Torres Strait.
Four rules underpin everything else, and they apply to every vessel at all times — there is no give-way vessel and no stand-on vessel until these are satisfied.
RULE 5 — LOOK-OUT
Maintain a proper look-out by sight and hearing, and by all available means appropriate to the circumstances — which now includes radar and AIS if you carry them. The phrase "all available means" is what makes ignoring an AIS alarm a breach, not merely bad practice.
RULE 6 — SAFE SPEED
A speed at which you can take proper and effective action to avoid collision and stop within a distance appropriate to the conditions. The rule lists what to weigh: visibility, traffic density, your vessel's manoeuvrability and stopping distance, background shore lights at night, wind, sea and current, your draught against the depth of water, and — if you have radar — its range scale, sea and rain clutter, and its blindness to small close targets.
RULE 7 — RISK OF COLLISION
Use all available means to determine whether risk exists, and assume it does if you cannot tell. The examinable test: if the compass bearing of an approaching vessel does not appreciably change, risk of collision exists. This is the constant-bearing, decreasing-range situation — CBDR. Take a hand-bearing compass reading, or line the other vessel up against a stanchion and hold your head still. If she stays on the same part of your boat, you are going to hit her. Be suspicious even of an appreciable bearing change when the other vessel is very large or very close.
RULE 8 — ACTION TO AVOID COLLISION
Any action must be positive, made in ample time, and large enough to be readily apparent to the other vessel — visually or on radar. A succession of small alterations is specifically discouraged. Make the turn big enough that the other skipper cannot miss it.
- Rule 9 — Narrow channels. Keep as near to the outer limit on your starboard side as is safe and practicable. Vessels under 20 m and sailing vessels must not impede a vessel that can only safely navigate within the channel. Do not anchor in a narrow channel.
- Rule 10 — Traffic separation schemes. Proceed in the lane's direction of flow; cross lanes as nearly as practicable at right angles. Vessels under 20 m, sailing and fishing vessels must not impede a power-driven vessel following a lane. Relevant at Port Phillip Heads, Torres Strait and the major port approaches.
- Rule 12 — Two sailing vessels. Different tacks: the vessel with the wind on her port side keeps clear. Same tack: the vessel to windward keeps clear. If you cannot tell which tack the other is on, you keep clear.
- Rule 13 — Overtaking. The overtaking vessel keeps clear, always, regardless of type — a yacht overtaking a motor cruiser still gives way. You are overtaking if you approach from more than 22.5° abaft her beam, which at night is the arc where you see only her white sternlight. The duty persists until finally past and clear.
- Rule 14 — Head-on. Two power-driven vessels meeting on reciprocal courses: each alters to starboard, so each passes port to port. At night you will see both her sidelights and both masthead lights in line.
- Rule 15 — Crossing. Two power-driven vessels crossing: the vessel that has the other on her own starboard side gives way, and should avoid crossing ahead. "If to starboard red appear, 'tis your duty to keep clear."
- Rules 16 and 17 — Give way and stand on. The give-way vessel takes early and substantial action. The stand-on vessel maintains course and speed — but may act alone as soon as it is apparent the other is not giving way, must act when collision cannot be avoided by the give-way vessel alone, and when doing so should not alter to port for a vessel on her own port side.
- Rule 19 — Restricted visibility. Safe speed, engines ready for immediate manoeuvre. A vessel detected by radar alone: avoid altering toward a vessel forward of the beam, and avoid altering toward one abeam or abaft the beam. Hearing a fog signal forward of the beam, reduce to bare steerage way and if necessary take all way off.
Rule 18 — the pecking order
The hierarchy every candidate memorises. Each vessel type keeps out of the way of everything above it. Note where sailing vessels actually sit: below fishing boats, and above nothing but power-driven vessels — the popular belief that "sail has right of way" is wrong in three separate directions at once, because Rules 9, 10 and 13 all override it.
1 Not under command
A vessel unable to manoeuvre as required through some exceptional circumstance — steering failure, engine failure. Two black balls, or two all-round red lights. 2 Restricted in ability to manoeuvre
Constrained by the nature of her work — dredging, cable-laying, servicing a navigation mark, replenishing at sea, launching aircraft. Ball-diamond-ball, or red-white-red. 3 Engaged in fishing
Nets, lines or trawls deployed that restrict manoeuvrability. A boat trolling a lure is not
"engaged in fishing" for this purpose — recreational anglers do not get priority. 4 Sailing vessel
Under sail alone. The moment the engine goes on you become a power-driven vessel, whatever the sails are doing — and you must show a cone, point down, by day. 5 Power-driven vessel
Gives way to everything above. Seaplanes on the water generally keep clear of all vessels.
Sitting outside the ladder is the vessel constrained by her draught, showing a black cylinder or three all-round red lights. She does not outrank sail or fishing outright, but every other vessel should give her as much room as practicable — and she must herself navigate with particular caution. In practice, in a dredged channel in a commercial port, give her the channel and stay out of it.
AMSA's own marine notices single out vessels under 20 m, sailing vessels and fishing vessels for the good-seamanship obligation, and stress radar reflectors and AIS for small fibreglass and timber craft, which return almost no radar echo. A ship's bridge team may genuinely not see you, may not be able to alter for you in a channel, and may take a mile or more to stop. The rules say she gives way to you; physics says you should not be there.