Indoor winter storage facilities are practical - with a solid roof over your head, i.e. a boat, you can work reasonably comfortably even in adverse weather conditions. But the roof also absorbs light. Only a few sheds are equipped with large skylights and window strips, and even with them it remains gloomy on a gloomy winter's day. If the boat is favourably positioned under a light strip, you may be able to work on deck. However, it is almost impossible to avoid additional lighting on the underwater hull at the latest, as the closely spaced hulls cast additional shadows.
Some skippers still rely on construction spotlights with halogen rods. Inexpensive and obviously very bright, they seem well suited to the purpose. However, the power consumption of up to 500 watts per lamp is not only detrimental to the electricity bill, but also quickly leads to a power failure in poorly secured halls. With just two spotlights, it is barely possible to operate a sanding machine and extractor.
In addition, most of the energy is lost as heat radiation. This can be recognised by the heat generated by the spotlights and is clearly evident when the electrical power consumption is compared to the luminous flux emitted. The luminous flux describes the part of the radiation that is emitted in the visible range of the spectrum; it is measured in lumens. Conventional halogen spotlights with 400 to 500 watts produce around 8,700 lumens. This corresponds to a yield of 17 to 22 lumens per watt. Modern light sources such as LEDs achieve 60 to 100 lumens per watt, depending on the design, and even fluorescent tubes are well ahead of halogen spotlights at around 90 lumens per watt, meaning they convert a much larger proportion of electrical energy into light.
LED spotlights are significantly more efficient
In practice, an LED spotlight requires only around a tenth of the electrical energy of a halogen spotlight with the same light output. However, the luminous flux says nothing about the direction in which the light is emitted. Halogen rods and fluorescent tubes emit light all round, so around two thirds of the light has to be deflected by a reflector in order to shine forwards. This results in losses. LEDs, on the other hand, emit light in a focussed manner from the outset and do not require reflectors.
However, the poor efficiency of halogen spotlights also has a positive side. In winter storage, it is often difficult to maintain the processing temperatures of synthetic resins. Gelcoat repairs are particularly critical, as polyester resins hardly cure below 15 degrees. A suitably positioned halogen spotlight provides the necessary heating and warms the hull area without stirring up a lot of dust. To prevent the laminate from overheating and being damaged, the minimum distance should be observed, as the radiators can reach temperatures of over 300 degrees.
Halogen light distorts the colours
Another disadvantage of halogen light is its colour. It is specified as the colour temperature and is around 2,900 Kelvin. This creates a cosy atmosphere in the home, but is not ideal for working - a body that is white in daylight appears yellowed in the light of the spotlight.
Even more problematic than the wrong colour is the effect of the warm white light on human vision, as contrasts are perceived much less clearly. This explains why many a hull that has been painstakingly polished in halogen light appears cloudy in the first ray of sunlight. The fine nuances of the unevenly polished wax simply cannot be recognised as well in yellowish light as in comparatively cold daylight.
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There are also differences in the light colours. At 4,000 Kelvin, even the cheap DIY store models are significantly colder than a halogen spotlight, and as the power of the LEDs increases, the colour tone of the light becomes even more similar to daylight. This increases the chance of actually polishing the hull without clouds.
The fluorescent tube - favourable and good
For polishing and painting work, the most uniform and daylight-like illumination possible is an advantage. Probably the cheapest way to achieve this is a combination of fluorescent tubes. In the simplest version, a 1.20 metre long light strip with 36 watts costs just 5 euros. If you choose a more robust damp-proof version with housing, you will have to pay around 10 euros per tube.
The individual strips do not produce a great deal of light, as the nominal 3,200 lumens are emitted all round and are not focussed by a reflector. However, a combination of five to ten tubes mounted at a distance on a white board provides very good lighting. If you are not confident about wiring, you can have the prepared board and tubes professionally wired by an electrician.
The light colour can be controlled by the choice of tubes and should be 6,500 Kelvin or more. The three-digit numerical code after the tube's wattage is more meaningful than designations such as "warm white" or "cool daylight". The first digit stands for the colour rendering and is usually an 8. The next two digits indicate the colour temperature in Kelvin, for example 65 for 6,500 Kelvin.
Due to the enormous size of the light source, there are hardly any problems with shadowing and alignment. A practical working position can be achieved by suspending the light unit from the hull of the neighbouring boat - a demonstration of the design usually gets the neighbours to agree.
Such a light unit is too bulky for work below deck. However, if larger areas are to be painted, it is worth experimenting with individual light strips. In the interior, their light intensity is usually sufficient. The edges of the housing can be softened with cut-away pipe insulation.
With LED spotlights, panel lights and fluorescent tubes, there is a whole range of good alternatives to halogen construction spotlights that not only provide better light, but also offer a wider range of applications. At the latest when the supply of light rods is used up again, it is worth thinking about completely replacing the work lighting and perhaps investing in a new system.
