Top tips: lights and shapes 

It doesn't matter how experienced a sailor you are, the many variations of navigation lights and day shapes are one of those things that tend to be forgotten over time but they are a vital aspect of navigating safely.   

After all, at night, in a busy channel, understanding different light configurations can make the difference between being deeply confused and having a very clear picture of what's going on.

Here are the lights and shapes required to be shown by the main types of boat you will be encountering.  

Vessels under seven metres and capable of less than seven knots:

• Need to display a single white light astern. There is no day shape.

Powered vessel under 50 metres:

• Needs to show a white masthead light, a white sternlight and port and starboard lights. There is no day shape.

Powered vessel over 50 metres:

• Needs to display two white masthead lights, the forward one lower than the aft. In addition to this, there would be port and starboard lights and a stern light. There is no day shape.  

A yacht under sail:

• Needs to display a tricolour white/red/green light at the top of the mast or port and starboard lights and a white stern light.
• An alternative to this is a red light over a green light.

There is no day shape, but if a vessel is motor sailing, it should display an inverted triangle.

Any vessel at anchor:

• Vessels under 50 metres need to show a single white light, while vessels over 50 metres should display two white lights, with the stern one lower than the bow.  

It is worth noting that many large vessels switch on their deck lights while at anchor, making it very clear that they are not underway. The day shape is a black ball.

Vessel engaged in diving operations:

• Dive boats should show a code flag. 

At night they should show the restricted in ability to manoeuvre light configuration (see below). 

Vessel engaged in fishing (not trawling):

• These show the usual lights for a powered vessel with the addition of an all round red light above its white light.

• The day shape is two triangles, apexes touching.

Vessel engaged in trawling:

• This is the same as a vessel fishing except an all round green light replaces the all round red.

• The day shape is the same as for trawling.  

Vessel restricted in its ability to manoeuvre:

• Should show the usual lights but also a red-white- red combination at its masthead.

• The day shape is two balls with a diamond between them.  

A vessel towing:

• A vessel towing displays an additional white masthead light. If the tow is less than 200m long. Two additional white masthead lights are shown if the tow is longer than 200m.  

• The day shape is a diamond on both vessel and tow.

These are some of the basic lights and shapes which will give you a better picture of what is going  on  in the seas around you. Obviously there are more, but these are the basics.

Even an experienced boater can forget these from time to time, so it is well worth testing yourself.