COLREGs (RIPA): steering rules, lights and signals for the PER and PNB

What are the COLREGs (RIPA) and why do they weigh so much in the exam?

The RIPA (International Regulations for Preventing Collisions at Sea, the COLREGs) are the «highway code» of the sea: they say who has priority, who must keep out of the way and how ships signal to each other. In the PER exam it is the largest block and, moreover, eliminating (you need a minimum number of correct answers to pass). Mastering it is, together with buoyage, what most decides the result.

The COLREGs are organised into parts: general matters and definitions, steering and sailing rules, lights and shapes, and sound signals. This guide covers the essentials of each.

Conduct in any condition of visibility

These rules always apply, whether or not you can be seen:

• Look-out (Rule 5): keep an efficient look-out at all times, by sight and hearing.
• Safe speed (Rule 6): proceed at a speed that lets you manoeuvre in time to avoid a collision, according to visibility, traffic, the state of the sea and your manoeuvrability.
• Risk of collision (Rule 7): use every available means to assess it. If the bearing of another vessel does not change and she draws closer, there is risk. If in doubt, the risk is deemed to exist.
• Action to avoid collision (Rule 8): make it clear, in good time and ample, so the other vessel readily notices it. A succession of small changes is no good.
• Narrow channels (Rule 9): keep as close as possible to the starboard limit of the channel.

The three situations between vessels in sight of one another

When two power-driven vessels approach with risk of collision, there are three situations:

1. Overtaking (Rule 13). If you approach another from more than 22.5° abaft her beam (at night you would see only her sternlight), you are the overtaking vessel and you keep out of the way. You remain obliged to keep clear until you are finally past and clear.

2. Head-on (Rule 14). If you approach bow to bow or nearly so (at night you would see both her sidelights and/or her masthead lights in line), you both turn to starboard to pass each other port to port. If in doubt whether this is the situation, assume that it is.

3. Crossing (Rule 15). If you cross, the vessel which has the other on her own starboard side gives way, and keeps clear avoiding crossing ahead of her. The other vessel keeps her course and speed (Rule 17), although she may manoeuvre if she sees that the give-way vessel is not acting; and, if she manoeuvres, she will not turn to port for a vessel on that side. The give-way vessel (Rule 16) must act early and substantially.

Sailing vessels among themselves (Rule 12)

When two sailing vessels approach:

• If they have the wind on different sides, the one with the wind on port gives way.
• If they have the wind on the same side, the windward one (the one up-wind) gives way to the leeward one.

The «hierarchy»: obligations between categories (Rule 18)

When vessels of different types meet, there is an order of priority. A power-driven vessel must keep out of the way of:

• a vessel not under command,
• a vessel restricted in her ability to manoeuvre,
• a vessel engaged in fishing,
• a sailing vessel.

In turn, a sailing vessel keeps out of the way of those not under command, restricted and fishing. A simple idea: the less a vessel can manoeuvre, the more priority it has.

Conduct in restricted visibility (Rule 19)

In fog or darkness where you cannot see one another: proceed at safe speed, with the engine ready to manoeuvre. If you hear the fog signal of another vessel forward of the beam or you cannot avoid a close-quarters situation, reduce to minimum or stop. If you manoeuvre by radar, avoid —except when overtaking— turning to port for a vessel forward of the beam.

Lights and shapes (the essentials)

At night, the lights tell you the type of vessel and where it is heading. The basic ones:

Sidelights: red to port and green to starboard, each visible over an arc of 112.5°.

Sternlight: white, visible 135° aft.

Masthead light: white, on the centreline, visible 225° forward. It is carried by power-driven vessels; sailing vessels under way do not carry a masthead light (only sidelights and sternlight).

By combining what you see you work out the aspect: two sidelights ahead → you have her bow-on; only the red → you see her port side (she crosses to your right); only the white sternlight → you are overtaking her.

By day, some key shapes:

Vessel not under command: two black balls.

Vessel at anchor: one black ball forward.

Sailing vessel also using the engine: a cone, point down (for COLREG purposes it is a power-driven vessel).

Sound signals

They warn of your manoeuvres and your presence. Between vessels in sight of one another (Rule 34):

• 1 short blast → «I am turning to starboard».
• 2 short blasts → «I am turning to port».
• 3 short blasts → «I am operating astern propulsion».
• 5 (or more) short and rapid blasts → doubt or danger signal: «I do not understand your intentions» or «I doubt whether you are taking sufficient action».
• In a narrow channel, approaching a bend with no visibility: one prolonged blast.

In restricted visibility (Rule 35), at intervals of no more than 2 minutes:

• Power-driven vessel making way: one prolonged blast.
• Power-driven vessel stopped (not making way): two prolonged blasts.
• Vessels not under command, restricted, sailing, fishing or towing: one prolonged followed by two short.
• At anchor: rapid ringing of the bell for about 5 s, at intervals of no more than 1 minute.

How to pass the COLREGs block

• Do not memorise isolated rules: understand who keeps clear and why (the less manoeuvrable, the more priority). With that you solve most of the situation questions.
• Fix the three situations: overtaking (the overtaking vessel keeps clear), head-on (both to starboard), crossing (the one on the right gives way, the one who sees the other's red light).
• Memorise the blasts as a block: 1 starboard, 2 port, 3 astern, 5 doubt.

Frequently asked questions