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IRPCS Lights Test

This self test is designed to assist you with the Coastal Skipper/Yachtmaster Course

Lights are shown in the format that would be presented in the IRPCS exam. Select vessel type, aspect, size and status where appropriate

mystery tip

Category of vessel: Size of vessel: Aspect: Status:

Checks: Submitted: Correct:


Here you should be able to identify the type or category of vessel from it's lights

For example:
If you can only see the port (red) and/or the starboard (green) light, then it must be a 'Vessel under Sail'

If you see three verticle red lights in addition to the side lights then it must be a vessel 'Constrained by its Draught'

For the full configuration of light categories refer to the IRPCS
If we can see the forward or side aspect of a vessel we maybe able to determine its size:

For a vessel under power two mast head lights indicate that is is probably over 50m in length.  One indicates it is under 50m in length.

An additional mast head light on a vessel showing its trawling lights (green over white) indicates it is probably over 50m in length.

For vessels under sail port,starboard and sternlight displayed at the top of the mast in a tri-latern or tri-colour would generally mean the vessel is under 20m in length.  Whereas when displayed at deck level we can only say length unknown.

For vessels at anchor or agound - one white light indicates a length of under 50m, two means probably over.
This should be straightforward for all vessels making way and for most that are underway (see next tab)

If port and starboard sidelights can be see together we are seeing the bow or forward aspect.

If only a port (red) light can be seen then port aspect and green for starboard.

A white light alone may either be the stern aspect of a vessel making way or an unknown aspect of a vessel at anchor under 50m, or a power driven vessel under 7m.

There are exceptions to this for some vessels ('Fishing (both types)',  'Not Under Command' and 'Restricted in Ability to Manoeuvre') when they are underway but not making way  . For these vessels, when not underway, their side-lights would be extinguished - so we can only say aspect unknown.
Not Under Way : moored or aground
Under Way : not attached to the seabed or shore
Making Way : moving through the water

There are only 4 categories of vessel that are able to indicate if they are Making Way or Not Making Way by virtue of having their side-lights on or off respectively

They are:  'Fishing not Trawling','Trawling','Not Under Command' and 'Restricted in Ability to Manoeuvre'

For all other categories we may only say that they are Underway (even if they may be Making Way, or even they are displaying their steaming/mast headlight)

For example:
A trawler only showing Green over White is Underway but Not Making Way
A trawler showning Green over White plus side-lights is Making Way (and also Underway)
A vessel showing 3 red lights vertical, 2 mast headlights and sidelights (ie. Constrained by Draught, under power, prob over 50m in length) can only be said to be Underway even though they may well actually be making way.


The reason for this is because they are the four categories of boat that might choose to be Not Making Way because of their situation or their operations.
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