LED navigation lights and replacement LED bulbs can seem anattractive proposition for yachtsman wishing to reduce powerconsumption. However, life, as usual, is not that simple.
No performance standard
As yet, there is still no international performance standard for small craft navigation lights, due in part to differences on both sides of the Atlantic over an earlier proposed standard intended for both incandescent and LED light sources. This means there is no method of knowing that an LED used for navigation will perform satisfactorily throughout its service life.
However, the ISO Technical Committee 188, responsible for small craft standards up to 24m LOA, has recently agreed to develop a standard specifically for LED lights. The RYA is involved in this work as a member of the European Boating Association.
Nevertheless, until the standard has been published, there are a number of pitfalls to using LED lights for navigation that recreational boaters should be aware of and which might not always appear in ‘the blurb’.
Fundamentally, all navigation lights must:
- Comply with the requirements in COLREGS (1972), Annex 1.
- Function satisfactorily without introducing intolerable electromagnetic disturbances to other equipment in the environment in which they operate.
I do not intend to get into the science of LED here, suffice to say they are electronic light sources that Produce colour according to the type semiconductor used.
The wrong colour
If you fit the type of bulb shown on the left in navigation light housings normally designed for incandescent filament bulbs then you may well have a problem.
Many are made from cheaper semiconductors that tend to give a ‘hard’, bluish light.
When these bulbs are placed behind conventional navigation light lenses the observed colour may be considerably different from the colours specified in COLREGS, and at worst may not be recognised as navigation lights.
Exceeds the cut-off sectors
The COLREGS state that: ....In the forward direction ….the intensities shall decrease to reach practical cut off between 1 and 3 degrees outside the prescribed sectors.
Incandescent navigation bulbs have vertical filaments to overcome this.
If the ‘hedgehog’ bulb shown above is fitted then it is likely that the horizontal cut–off sectors will be exceeded. This is equally true if you buy an LED replacement navigation light unit where the LEDs are arranged around its circumference.
In part two, next month (July 2012), I will cover other aspects of LED navigation lights, such as colour stability and luminosity and the potential problems caused by electromagnetic interference.
Stuart Carruthers RYA Cruising Manager