Navigation lights tend to be very difficult to identify correctly at night. Can you remember the difference between a vessel towing astern with a tow length more than 200 meters and a vessel with a tow length less than 200 metres?

The LIGHTrule claims to provide a quick and easy way to look up the light configuration for any given vessel, and is also a practical alternative to flick cards for learning lights and shapes in the first place

£14.95 from Bookharbour.com