Rule 1: where the COLREGs apply.

What does COLREGs Rule 1 say?

Rule 1(a): the rules apply to all vessels on the high seas and in all waters connected to them that are 'navigable by seagoing vessels'.

Rule 1(b) and (c) leave room for special rules — local rules for harbours, rivers and other inland waters, and extra signals that a government may set for warships, convoys and fishing fleets. Rule 1(d) says traffic separation schemes may be adopted by the Organization (the IMO). Rule 1(e) covers vessels of special construction or purpose that cannot fully comply with the rules on lights, shapes and sound-signalling appliances.

Where do the COLREGs apply?

On the high seas, and in all waters connected to the high seas that seagoing vessels can navigate. That takes in coastal waters, estuaries, harbours and rivers, as long as they are connected and navigable by seagoing vessels.

As we read Rule 1(a), a lake or inland waterway that is not connected to the sea, or that seagoing vessels cannot navigate, falls outside it. Such waters normally have their own rules, and those are the ones to check.

Which vessels do the COLREGs apply to?

All of them. Rule 1(a) says 'all vessels', and Rule 3(a) defines a vessel as every description of water craft used or capable of being used as a means of transportation on water — including non-displacement craft, WIG craft and seaplanes. A tender or a rowing boat is as much a vessel under the rules as a container ship; Rule 25(d)(ii) even provides for lights on a vessel under oars.

In the UK, MSN 1781 (in the sources below) states that the rules apply by virtue of the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996.

What are the 'special rules' in Rule 1(b)?

Rules made by an appropriate authority for roadsteads, harbours, rivers, lakes or inland waterways that are connected with the high seas and navigable by seagoing vessels. Rule 1(b) says nothing in the COLREGs interferes with how those special rules operate — provided the special rules 'conform as closely as possible' to the COLREGs.

In practice they range from a single port's byelaws or local regulations to whole national codes for inland waters, such as the United States' Inland Rules. Local notices, pilot books and the harbour authority are where you find them.

Do local rules replace the COLREGs?

Not as a whole. As we read Rule 1(b), the local rules operate where they apply, and the COLREGs still govern everything the local rules do not change. Where a local rule says something different, follow it in that water; where it is silent, the COLREGs apply.

In practice, that is why a passage plan into a port includes its local regulations: a vessel can comply with every COLREG and still break a harbour's rules on speed, channels or signals.

What does Rule 1(c) allow?

Rule 1(c) lets the government of any state make special rules adding station or signal lights, shapes or whistle signals for 'ships of war and vessels proceeding under convoy', and adding lights or shapes, but not whistle signals, for fishing vessels 'engaged in fishing as a fleet'.

So far as possible, those extra signals must not be open to confusion with any light, shape or signal the rules authorise elsewhere. In practice, an unfamiliar arrangement of lights on a warship or around a convoy may be one of these, and it calls for caution rather than guesswork.

What does Rule 1(d) say about traffic separation schemes?

Only that they may be adopted by the Organization — the IMO — for the purpose of the rules. Rule 10(a) then applies Rule 10 to traffic separation schemes 'adopted by the Organization'.

As we read the two together, a scheme set up locally and not adopted by the IMO falls outside Rule 10's own wording; check the local regulations for how it is to be used.

What is a 'vessel of special construction or purpose' under Rule 1(e)?

A vessel that, as the Government concerned determines, cannot comply fully with the rules on the number, position, range or arc of visibility of lights or shapes, or on the disposition and characteristics of sound-signalling appliances. She must instead comply with whatever other provisions that Government determines to be the 'closest possible compliance' for her.

As we read it, the Government concerned is normally the flag state, and the provision is about the number, position, range and arc of visibility of lights and shapes, and the disposition and characteristics of sound-signalling appliances — the detail of which is in Annex I (positioning and technical details of lights and shapes) and Annex III (technical details of sound signal appliances). It does not excuse the vessel from the steering and sailing rules. The rule itself gives no examples.

How might Rule 1 come up in an MCA oral?

It may come up as an opening question or in a port-entry scenario. Examples of the kind of question to be ready for:

“Where do the COLREGs apply?”

“You're entering a port that has its own local regulations. Which rules apply to you?”

“Do the COLREGs apply on a lake?”

“Who adopts traffic separation schemes?”

“A warship is showing lights you don't recognise. How can that be allowed?”

Where do candidates go wrong on Rule 1?

The common slips: saying the COLREGs stop at the harbour entrance; treating local rules as if they replaced the COLREGs entirely; forgetting that special rules must conform as closely as possible to the COLREGs; and missing the condition in 1(a) — connected to the high seas and navigable by seagoing vessels — when asked about inland waters.