Light Fantastic

Not long ago I was bemoaning the fact that so many boatbuilders are still using highly inefficient incandescent and halogen lights, even though fluorescent lights have long been available and LEDs are now viable for most marine lighting applications. Since then, Neil Harrison, a reader from the UK, has pointed out that the next revolution in lighting may already be on the horizon—Organic
Author:
Updated:
Original:

Not long ago I was bemoaning the fact that so many boatbuilders are still using highly inefficient incandescent and halogen lights, even though fluorescent lights have long been available and LEDs are now viable for most marine lighting applications. Since then, Neil Harrison, a reader from the UK, has pointed out that the next revolution in lighting may already be on the horizon—Organic Light-Emitting Diodes, or OLEDs.

Before getting into this, let’s look first at the currently available technologies. Efficiency is not the only critical factor. Equally important are the beam angle, the color temperature, the color rendering index score, life expectancy in the marine environment and, of course, cost.

EFFICIENCY AND BEAM ANGLE

The efficiency of a light source is typically measured in terms of lumens of light output per watt of electricity consumed. Incandescent lights are generally below 10 lumens per watt, halogens around 15 lumens per watt, fluorescents between 50 and 100 lumens per watt, and LEDs anywhere from 20 lumens per watt to 60 lumens per watt, with the efficiency improving every year (in the laboratory LEDs rate at well over 100 lumens per watt).

Traditional light sources tend to radiate in all directions, but usually we want light projected in a specific direction, for example from the ceiling downward. If two lights are equally efficient, but one scatters light in all directions while the other projects it solely where we want it, the latter can be a lower-power fixture and therefore more efficient. Incandescents, halogens and fluorescents all scatter their light. LEDs concentrate it into a defined beam. In practice, an LED that puts out 60 lumens per watt is generally significantly more efficient than even a fluorescent running at 100 lumens per watt.


COLOR TEMPERATURE

Lighting is described as “warm” or “cold.” Warm light tends toward the red end of the light spectrum, while cool tends toward the blue end. Warmth can also be expressed in degrees Kelvin, or K. Warm light has a color temperature of around 2,700K to 3,000K. Cool light is 4,000K and higher. For interior boat lighting, we typically want something on the order of 2,700K to 3,000K. Most incandescent and halogen lighting is between 2,500K and 3,100K. Traditional fluorescent office lighting is around 4,000K, which is on the cold side, although compact fluorescents are now widely available with color temperatures as low as 2,700K. (The color temperature is generally given in the small print on the packaging.)

White LEDs actually create a very cold blue light that excites a phosphor coating on the inside of the LED’s lens. This coating is doped with optically active ions that convert some of the blue light into yellow light. The resulting blue-yellow mix is seen as white light. Most white LEDs are above 4,000K, and as such give a relatively cold light.

Although “warmer” lights with lower color temperatures are easier on the eyes, their light is less efficient—warmer LEDs are typically only 70 percent as efficient as cooler LEDs. Researchers are currently trying to manipulate LED phosphors in a way that will add red light to lower the color temperature without a loss of efficiency.

Another factor to consider when evaluating light quality is the ability of a light source to illuminate an object’s colors, as they would be seen under a natural light source. This is expressed through something known as the color rendering index, or CRI. Natural light has a CRI of 100. As the quality of light degrades, the CRI goes down. If the CRI is below 90, colors start to look unnatural to the human eye. Most incandescent and halogen lights have a CRI of 100. Compact fluorescents are usually around 90, although some are as high as 95. Most white LEDs are between 70 and 80, yielding a significant degradation of light quality, although some LEDs are now available with CRIs up to 90. One of the reasons for the low CRI of LEDs is the difficulty of ensuring a uniform mix of the blue and yellow light over the entire illuminated area.


LIFE EXPECTANCY

The life expectancies of the various forms of marine lighting vary enormously from what is achieved in the laboratory. This is primarily a function of the widely variable voltage on DC systems. A typical 12-volt system, for example, may range from as low as 11.0 volts when it is seriously discharged or under a heavy load to as high as 14.4 volts during the absorption phase of battery charging.

Halogens, in particular, suffer a sharp loss of life at the higher end of the voltage scale. LEDs in the “raw” state are also extremely sensitive to high voltage, and must be coupled with a “driver” that acts as a voltage regulator. The life expectancy of an LED is substantially dependent on the quality and sophistication of its driver. The latest drivers are incredibly sophisticated.

In general, the life expectancy of incandescents and halogens is measured in the low thousands of hours, while fluorescents can last tens of thousands of hours. LEDs vary, but can last as long as 50,000 hours.

The primary reason most boatbuilders still use incandescents and halogens is because of the relatively low purchase price. This, of course, is no measure of real cost, which must include efficiency and life expectancy. In this respect, fluorescents are particularly cost-effective. Meanwhile, the cost per lumen of light output from LEDs has decreased rapidly in recent years, while the gap with fluorescents is closing. If I were to build a boat today, I would seriously consider all-LED lighting. My current boat has fluorescent area lighting and LED reading and task lighting.

The OLED Revolution

An OLED has a very thin layer of organic material sandwiched between a negative and positive electrode layer. The whole thing is no thicker than several sheets of paper, less than 1 mm. When an electric charge is applied, the organic material is excited and produces light. These are the first electric lights that do not create a point source of light. Instead, a sheet of light is generated. Initially, OLEDs will be produced in panels of various sizes, but in time they will probably be coated onto walls, ceilings and other surfaces. If successful, OLEDs will radically change lighting and interior design concepts.

Predictions are that OLEDs can achieve higher efficiencies than even LEDs (currently, OLEDs produce up to 64 lumens per watt), with the necessary color temperatures, CRI, life expectancy and cost effectiveness to be viable. We shall have to wait and see. General Electric and Konica Minolta are leading the charge on OLEDs. Konica Minolta plans to open its first mass production facility later this year, with commercialization predicted for 2011.

It could be that by the time most boatbuilders finally get on the LED bandwagon, they will already be obsolete.

Related

Lee-Cloths-Lee-Boards-and-single-bunks-on-ISBJORN_by-Andy-Schell_Trans-Atlantic-2019

The Perfect Offshore Boat: Part 2

November, 2009: Mia and I were sailing our 1966 Allied Seabreeze yawl, Arcturus, on our first-ever offshore passage together, a short hop from Wilmington, North Carolina, to Jacksonville, Florida. Our second night out, the brisk northwesterly wind shut down, but the sea state ...read more

210727_JR_SE_Tokyo20_186871368

Tune in for Olympic Sailing

Today marks the start of 470 and NARCA 17 racing on Enoshima Bay, and racing in the other seven fleets is already underway. A few of the American sailors are already off to an impressive start, with Maggie Shea and Stephanie Roble currently in second place in the 49er FX, Luke ...read more

Happy-Cat

Boat Review: Happy Cat Hurricane

I’m not sure what I expected from my daysail on the Happy Cat Hurricane. One thing I do know is that the day didn’t go as planned. The SAIL staff was invited by Alex Caslow from Redbeard Sailing to Gunpowder State Park on Chesapeake Bay near Baltimore. We were to test several ...read more

210722_PM_Tokyo20_4910_5979-2048x

Olympic Sailing Guide

The Opening Ceremony for the Tokyo Games is finally here. From July 24 to August 4, sailors from across the world will be gathering on six courses on Enoshima Bay to race for gold. Ten classes will take part in the event: RS:X (men), RS:X (women), Laser Full Rig, Laser Radial, ...read more

01-LEAD-TobagoCaysHorseshoeColors

Chartering: Voltage is King

For some time now, both in the pages of this magazine and with individual charterers, I’ve talked about how important it is to pay close attention during a charter checkout. The idea is to listen “between the lines,” as it were, to be sure you aren’t missing any hidden red flags ...read more

AC75-No.-1

ETNZ May Abandon New Zealand

Remember when the Kiwis were the young, underfunded upstarts of the America’s Cup world, with right on their side as they took on the Big Bad Americans? Remember the withering criticism leveled at Larry Ellison when, in the wake of “The Comeback” on San Francisco Bay, arguably ...read more

01-LEAD-EX26_1119_dehler_30od_race_2nd_077_web_4zu3_300dpi2048x

Boat Review: Dehler 30 One Design

I’ve long believed that while they may not be as much fun, the best sail trials are the ones that take place in drifters since it’s then that a boat’s performance—or lack thereof—really becomes evident. Pretty much any boat is fun to sail in 15 knots of wind. That said, there’s ...read more

01-LEAD-Opener-DJI_0026-2048x

The Multihull Industry’s Major Builders

It’s a given that boatbuilding these days is a global industry, with sailboats going down the ways everywhere from the icy waters of Scandinavia to the South China sea. This includes the manufacture of multihulls—no surprise given their birthplace in the far-flung islands of the ...read more