COLREG

Those who are about to obtain a boating license will undoubtedly hear about COLREG at some point. This acronym stands for “regulation to prevent collisions at sea”, and it is an internationally recognized set of rules for lights and signals.

What’s in the COLREG, then?

First of all, we have specific rules for lights: in COLREG, the types of lights required according to one’s type of unit are described in detail, as well as specific signals that enable others to recognize for example the type of boat, hull length, or maneuverability.

With the right signals it is also possible to indicate whether the unit is sail or motor, or whether a vessel is employed in underwater work and is therefore a dredger, or a tugboat, or a fishing vessel. 

The COLREG also contains precedence rules for both sail and motor boats and allows for a better assessment of when there is a risk of collision.

But it is not just about light signals: the COLREG also includes sound signals that indicate maneuvering, overtaking, navigation in fog, and signaling of units at anchor, or rather at anchor.

Why is COLREG so important?

Night and day navigation questions and other signals feature heavily in ministerial quizzes, so it is worth studying them carefully.

In fact, COLREG is a set of shared rules that is fundamental to navigation in ports and in fact greatly limits boardings.

Definition of “boarding” 

A boarding is defined as a collision between two boats.

The term “collision” is perhaps more commonly used in common parlance, and sometimes even in the boating environment, but we tend to keep the term “boarding” precisely because of COLREG.

Let us now go into the details of the first chapter of COLREG: lights.

Lights

The first and most important method of signaling to avoid boarding according to COLREG is the lights, which must be on from dusk to dawn and at any time of the day when there is reduced visibility. 

For example: fog, snow, rain or sandstorm.

Lanterns must be displayed by all units when sailing at night more than one mile from the coast, although it is advisable to maintain them for safety even within one mile of the coast, and when sailing during the day.

Within 12 miles from shore, on the other hand, the only requirement is to have a white-light flashlight on board.

Regulatory lanterns should be visible to any type of vessel in any type of navigation and must be seen at 360°.

This provides for four basic lights in a vessel:

• the masthead light (at the bow);
• the companion light (at the stern);
• the side pathway lights.

Each of these lights must provide a certain angle of visibility (while one part is blind). The luminous part is the one colored in the figure below.

Mandatory lights

Let us now look at the mandatory lanterns in relation to hull length.

Let’s start with motor units and continue with sailing units.

1) Lights for motor sailing

Units less than 7 m with a maximum speed of 7 knots.

A single 360° white light is needed here. As we have already seen, a flashlight is also suitable, and side lights also combined into a single combined light are optional.

Units less than 12 m

Need a single combined lantern with a 360° white lantern, and two side way lights also combined into a single lantern.

Units less than 20 m

• One masthead lantern;
• Two side way lights also combined into a single green and red light; 
• One stern or crowning light.

Units less than 50 m

• One masthead light; 
• Two side pathway lights;
• One stern or crowning light.

Units greater than 50 m 

• Two masthead lights (one at the bow and one at the stern, 4.5 m higher than the one at the bow);
• Two sidelights; 
• One stern/crowning light.

2) Lights for sailing

Here again we see the minimum mandatory lanterns in relation to hull length.

Units less than 7 meters

A single 360° white light applies and a flashlight is also suitable. On the other hand, side marker and companion lights are optional, even combined into a single combined light.

Units less than 20 meters

A single combined lantern exposed as high as possible with two side way lights and a stern or crowning light or alternatively two side way lights (also combined into a single lantern) and a stern or crowning light is required.

Units greater than 20 m 

Two side path lights and a stern or crowning light are needed here. 

What if the motor sail sails with the engine on?

A motor sailing unit becomes a motor unit for all intents and purposes because it is powered by a motor and therefore must display:

• One masthead light, and if it is over 50 m two lights, the one aft a little higher;
• Two side path lights; 
• A crowning light. 

By day, the sailing unit that is motoring must display a cone with apex downward.

All sailing units that do not display other lights at or near the masthead may display two optional 360° lights aligned vertically (red above and green below).