Marine searchlights are high performance equipment which should be chosen carefully and concidered as a stand-alone delivery in any project based on quality, performance, reliability, experience and availability and should not be concidered as a minor part of a complete marine lighting package from a volume vendor. There are big differences in optical performance, maintenance accesibility, material quality and spare parts accessibility between different products and brands which might look competitive seen only from a wattage/voltage/light source point of view.
Halogen searchlights
Halogen lamps have been used in the marine searchlight industry for decades. They are connected directly to main power withput any need for ballasts, ignitors or electronic power supplies. Halogen lamps are low-cost light sources and provide cost efficient light with limited range and light quality. Spread angle is normally fixed between 6-10 degrees and focus system has limited function.
Halogen lamps are efficient for melting snow and ice since the searchlight drum will become hot during operation. Lifetime can vary but for a 2000W halogen lamp normal life time is 400 hrs. Lamps can be easily replaced due to the standard socket system. Range for a halogen searchlight is normally 1500-2000 meters /1 lux. Halogen searchlight is not suitable for detection of ice, color temperature is apx. 3200K. Halogen lamps can not withstand vibrations.
When the light beam is focused to wide beam, typically a «dark hole» with less illumination occours in the center of the beam.
LED searchlights
LED searchlights can be compared to a very good halogen searchlight when it comes to range and performance but not as good as a HMI, Xenon or a Laser searchlight. Color temperature is higher than for Halogen, normally 5000K. LED is often chosen for vessels where only 24 VDC is available since more the powerful , traditional HMI and Xenon searchlights only are available for 230 VAC.
LED searchlights does not have stepless focus system and can only provide a fixed beam. On some LED searchlight models you can alter light between two different led diodes with different spread angle installed in the searchlight making some kind of a wide/narrow beam function but function is very limited compared to a proper stepless focus system used in searchlights with gas discharge lamps. LED searchlights does not need any external power supplies and can reach 20-30 000 hrs lifetime, but when they have reached end of life the entire searchlight unit normally needs to be replaced. Power range is most often 200-500 watt. LED does not generate heat and can neither be exposed to the amount of heat which is required to melt snow and ice, so even with heating elements installed in the searchlight drum a LED searchlight will not perform good in cold demanding conditons since the drum temperature is limited to 35-40 degrees celsius. LED can withstand vibrations.
HMI searchlights, (also called Metal Halide lamps).
HMI lamps have a blue spectrum and color temperature close to 6000K making them suitable for detection of ice. These searchlights are delivered in a range from 400-2500W for marine searchlights and use short arc lamps, not similar to conventional metal halide lamps used in floodlights etc. HMI lamps needs a warm up time of apx. 20-30 seconds before full light output is reached when being switched on from cold lamp making some limitations for use. Warm lamp can be re-ignited with full light output if switched off. HMI lamps has a lifetime of 500-1000 hrs. and can withstand vibrations.
HMI lamps can focus the beam more narrow and reach a longer range than a halogen searchlight but not as narrow as a Xenon searchlight thus providing range in the medium to long area. HMI lamps become hot during operation and has the ability to melt snow and ice provided that the wattage is high enough. HMI searchlights require a ballast to be installed in a technical room making the installation more complex than a halogen searchlight or a Laser searchlight. Normally electrical focus is standard for all HMI searchlights. The light beam is more «foggy» than a Xenon light beam and does not provide the perfect border between light and dark zone. HMI is in general concidered as a cost efficient option to Xenon searchlights with some limitations related to light quality, warm up time from cold start and range, but performance is way better than Halogen and LED searchlights.
When the light beam is being focused to wide beam, typically a «dark hole» with less illumination occours in the center of the beam.
Xenon searchlights
Xenon lamps has been used since the beginning of the 70’s in the marine industry, particulary on vessels operating in ice condition. Their ability to detect ice is excellent due to the color temperature of 6000K. They provide instant light immidiately when being switched on without any warm up time.
Xenon lamps provides the longest range of all searchlights and the zoom system provide a very clear border between dark and light area since the beam is technically more perfect than the beam from a HMI searchlight. Xenon searchlights require a ballast to be installed in a technical room making the installation more complex than a halogen searchlight or a Laser searchlight.
Normally electrical focus is standard for all Xenon searchlights. Power is most often in range 1000-3000 Watt for Xenon searchlights. Xenon lamps has a lifetime of 2000-2500 hrs, more than double of a HMI lamp. and can withstand vibrations. The drum temperature can reach 120-130 degrees celcius during operation and the heat from the powerful beam can easily melt snow and ice in cold conditions. Xenon searchlight performs best among searchlights with gas discharge lamps (HMI, Metal Halide and Xenon).
When the light beam is focused to very wide beam, typically a «dark hole» with less illumination occours in the center of the beam due to the reflector optics.
Laser searchlights
Laser is concidered as the forth and last generation light source after incandescent, tungsten, fluorescent, discharge and LED light. Laser brings searchlight technology a major step forward eleminating use of traditional bulbs, reflectors, ignitors and lamp ballasts.
Laser in fact outperforms all other searchlights on the market when it comes to quality of light, range, focus abilities, maintenance and operational expenses. Laser creates a perfect light beam without any stray light in addition to a lifetime of 12000 hrs making these searchlights the very best choice for all purposes. When reached end of life, the laser unit mounted inside the searchlight drum can easlily be replaced with a new one.
Laser searchlights has excellent ability to detect ice, same as for Xenon due to the 6500K color temperature. They have very low power consumption and requires no maintenance. The size of a Laser searchlight is much smaller than a HMI or a Xenon searchlight (only 1/3 front glass area) while the light output is much more powerful. Making the Laser searchlight more robust to mechanical exposure and easier to install. In fact, a 500W laser searchlights provices illumination power equal to a 3500W Xenon searchlight but with a more perfect light beam, smaller size, less maintenance and less complex installation.
Electrical focus is standard and the beam can be focused wider than for any other searchlight without generating any «dark hole» in the center of the beam since the beam is generated by advanced lens technology and not reflectors. Laser is providing sufficient heat from the light source to work efficient also in harsh weather and cold arctic conditions.
Power range is normally 250-500 watt.