The RYA’s Cruising Manager revisits the pros and cons of using LED lights for navigation following publication of a new international standard.
LED light sources are an attractive proposition for any yachtsman who wishes to reduce power consumption and extend battery life. However, as we have previously explained, the not so obvious downside was that what you bought might look fine to you, but there was there is no way of knowing that an LED light was compliant with COLREGs in terms of colour, cut off angles and range.
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. This could well confuse the watch keeper on the bridge of a large commercial vessel coming your way.
|This may cause problems if you fit the type of LED bulb shown here as a replacement for incandescent filament bulbs. Many LEDs are made from cheaper semiconductors that tend to give a ‘hard’ bluish light. When such bulbs are placed behind conventional navigation light lenses the observed colour may be considerably different from the colours required in COLREG72 and at worst may not be recognised as navigation lights at all. In addition the lens itself may well reduce the observable range or luminous intensity of the light.|
|The second problem comes with cut-off angles. COLREG72 states that: ....In the forward direction sidelights as fitted on the vessel shall show the minimum required intensities. The intensities shall decrease to reach practical cut off between 1 and 3 degrees outside the prescribed sectors. That is why an incandescent bulb has a vertical filament. If the ‘hedgehog’ LED bulb show above is fitted or you buy an LED replacement Navigation light unit where the LEDs are arranged around the circumference, it is possible that the horizontal cut–offs will be exceeded as shown in the diagram.|
Apart from colour and cut off arcs, there are a number of other problems that can affect LED light sources that must be assessed against a technical standard if they are to provide assurance for the user.
For example, heat and cold can affect the LED colour which needs to be maintained within the boundaries of the COLREG colour requirements. LED must be protected from voltage spikes, shorting or mechanical failure inside the lamp due to moisture, impact, shock and vibration. They may also interfere with other electronic equipment on board if not filtered.
Some manufacturers have invested significant time and effort to ensure their LED navigation lights can perform in the harshest environments without degradation or failure. Other manufacturers may not have been so diligent. Fortunately there is now a solution.
In 2012, the RYA proposed that an International Standard that specifies requirements and testing for navigation lights with permanently fixed LED light sources should be developed for small craft of up to 24 m LOA. As a result the standard, (EN ISO 19009:2015 Small craft - Electric navigation lights – Performance of LED lights) has now been published. This provides a means for LED navigation light manufacturers to show that their products are of adequate quality, conform to the COLREGs requirements and will perform reliably.
It is an inescapable fact that decent LED units may not be cheap. However, the cost may be acceptable compared with the lifecycle costs and the obvious advantages of knowing that something is performing as it should.
Stuart Carruthers, RYA Cruising Manager
This article was published in December 2015.