Best Navigation Lighting.

[freedgabriel]

Originally Posted by michaelparez

yeah it sounds good. But when we ask the shop guys about this they will tell everything positive. So we are enable to find the exact quality things,,,,


london plumber

yeah, he is true,,,, we have to find ourselves instead of be-leaving vendors words,,,,,


ceramic brakes | ceramic brakes pads

[D.I.M.1]

To summarize most of the posts:
Go LED?

[Fanie]

Led's are great for small areas like in boats. If you need more bright light in larger areas then I would suggest compact fluorescent.

The LED board I made has 3 x 1W LED's on them. I tested it on my friend's house boat, and it looks impressive. Keep in mind the white enhances the light quite a lot.

Be aware of the led boards that uses switchmode stuff to increase the voltage to drive multiple LED's with. They emmit a lot of noise and may cause problems to rf equipment.

[hoytedow]

Incandescent is less toxic than fluorescent and more "green".

In general LED is the right way, yes.
Though Fanie made some valid comments. Do´nt forget the high power LED gets HOT!

[hoytedow]

Base of compact fluorescent gets hot, too, and if it breaks nasty stuff in tubes is not good for you.

[hoytedow]

Health issues section - Wikipedia:
Special handling instructions for breakage are currently not printed on the packaging of household CFL bulbs in many countries. The amount of mercury released by one bulb can temporarily exceed U.S. federal guidelines for chronic exposure.[53][54] Chronic however, implies that the exposure continues constantly over a long period of time and the Maine DEP study noted that it remains unclear what the health risks are from short-term exposure to low levels of elemental mercury. The Maine DEP study also confirmed that, despite following EPA best-practice cleanup guidelines on broken CFLs, researchers were unable to remove mercury from carpet, and agitation of the carpet—such as by young children playing—created spikes as high as 25,000 ng/m3 in air close to the carpet, even weeks after the initial breakage. Conventional tubular fluorescent lamps have been in commercial and domestic use since the 1930s with little public concern about their handling; these and other domestic products such as thermometers contain far more mercury than modern CFLs.

[Fanie]

Hoyt, we make CF's that works from 12V. They are compact, and if in any kind of decent housing they can withstand a lot of abuse.

I've had a customers losing their cargo offe'n their roof and the lights went sliding down the road after them. They all worked and not a single lamp broke. My own dear friends go fishing with my lights and when it starts to rain leave their lights out in the pouring rain. Not one compact bust it's hot lamp from the water.

There are no poisenous gasses in these tubes.

Incandescent is less toxic than fluorescent and more "green".

BS But the Incandescent is very toxic to battery life. They bust when even one drop of cold water spills on the glass, and their life expectancy is not so hot. Personally I hate changing light bulbs, isn't that what blonds do ?


As for the heat generated by high power LED's, it is unfortunately true. LED's do however have an interesting curve if you compare current vs light output. Up to 50 to 70% of the current already produces 80 to 90% of the light, so it is more economical not to drive the LED flat out.

The LED will also run a lot cooler, you save a bit of power and you still get most of the light from it. I drive my LED's up to 225mA with it's max at 350mA, which is about 65%. The difference between 225mA and 350mA in light output is not worth the extra current.

The biggest gain is probably the gained life of the LED's. The hotter a LED is running the shorter it lives. The LED's I use have a said life of 100 000 hours, that is ten years, but it would be nice if they still work 20 years from now.

By then I hope something even more economical would be out... maybe the world would wake up and produce harmless radio active sources that produces lights with 30 year half lives. Remember the lights they used on the life boats in WW2 ? You can buy glow sticks off the shelf, some of these glow for a week on end. Some weak phosporic something, a chemical reaction between two liquids.

[hoytedow]

I prefer LED over CFL because the light production is more dependable. I do notice a marked diminution of light output from CFL bulbs over time. Something that is avoided with LED and IL.

Originally Posted by Fanie

Up to 50 to 70% of the current already produces 80 to 90% of the light, so it is more economical not to drive the LED flat out.

That is a really interesting information, I did not know that. That simply means install one more and run them at 80% max. ?

If that is true (and I think you know what you are talking), that goes right down to the shop floor.

[Fanie]

Re Health issues section - Wikipedia: When was the article placed...

I don't see how they ban anything mercury and then put it into CF's

I prefer LED over CFL because the light production is more dependable.

That depends. CF's have a life span of up to around 10 000 hrs, but it is quality light. Some LED's doesn't make it to so many hours, but it also depends how hot they are run. Some LED light manuf will overdrive them to show more light, but the deminishing light you will discover only over a couple of months, usually shortly after you threw the guarantee papers away

I do notice a marked diminution of light output from CFL bulbs over time. Something that is avoided with LED and IL.

LED's also go dimmer over time. Again, it depends how hard you drive them and how hot they run.

One of the biggest advantages of LED's are that they are easily dimmable. One seldom needs full brightness, so if not required and you run them dimmer, they will last a LOT longer.

That is correct Richard, easy to test as well. Two resistors and a LED on a battery. Test it at night

Attached is a typical LED Illum to current graph. Keep in mind one have to consider the spectrum of the visibilty of the LED also.

They used red lights in the old days to prevent night blindness, I have to see if green has the same effect as the red.
I would like green night lights rather than red. Unless of course you are looking to attract certain people to the boat then stick to red

Originally Posted by Fanie

They used red lights in the old days to prevent night blindness, I have to see if green has the same effect as the red.
I would like green night lights rather than red. Unless of course you are looking to attract certain people to the boat then stick to red

Green does not work as good as red. The human nature is the reason, our eyes can recognize (or better to say are attracted by?) green light better than the rest of the spectrum. When one goes blind, green is the last light to disappear.

At night that is not helpful

[Fanie]

@ http://stlplaces.com/night_vision_red_myth/


Night Vision
The Red Myth

Unaided night vision even now in the 21st century is still the subject of some controversy.

For those just looking for an executive answer as to what supplemental lighting should be used to reduced the recovery time back to night vision (dark adapted or scotopic) here it is: a fully dimmable white light! This of course is a very incomplete answer but so are the answers red or blue-green and you should know why.

Lets start with red, specifically what I will call the red light myth.

I believe the myth started in the photographic darkroom.

Until about 1906 most photosensitive material (plate, film, and paper) was not very sensitive to red. Some of these orthochromatic materials are still used. This allowed these materials to be dealt with for a short time under a relative bright red light because the human eye can see red if the level is bright enough. The fact that L.E.D.s (having a number of advantages over other light sources) were economically only available in red for some time has also help to perpetuate this myth.

As more research about the eye was done it was found that the structure responsible for very low light vision, the rods, were also not very sensitive to red.

It was assumed then that like film you could use red light, which is seen by the red sensitive cones (there are also blue and green sensitive cones to give color vision), without affecting the rods.

It takes a while for true night vision to be recovered. About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week. The issue is the chemical in the eye, rhodopsin - commonly called visual purple, is broken down quickly by light. The main issue then is intensity; color is only an issue because the rods (responsible for night vision) are most sensitive at a particular color. That color is a blue-green (507nm) similar to traffic light green (which is this color for a entirely different reason). It would seem that using the lowest brightness (using this color) additional light needed for a task is the best bet to retain this dark adaptation because it allows rods to function at their best.

Unfortunately there are a number of drawbacks using only night vision.

Among these are:
The inability to distinguish colors.
No detail can be seen (about the same as 20/200 vision in daylight).
That nothing can be seen directly in front of the eyes (no rods in the center of the retina), you must learn to look about 15-20° off center.
Only motion can be detected well, therefore you may have to learn to move your eyes to detect something that doesn't move.
Objects that aren't moving appear to move (autokinesis). This has probably led to a number of plane crashes.
If you need to see directly in front of you or see detail you need red. Like many myths the red light myth has some basis in fact. The red truth?

Why red? The center 1.5% of your retina (the fovea) which provides you with most detailed vision is packed almost exclusively with red sensitive cones.

This is the same area that has no rods and is responsible for the night blind spot. There are fewer total green sensitive cones than red. The number of blue sensitive cones is very small compared to green and red.

Which is just as well since the lens in the human eye cannot focus red and blue at the same time. And using green really only changes perceived brightness because of the way the signals are processed in our neural pathways. Unlike a digital camera, more pixels, in this case, doesn't give us more detail.


Chart showing the distribution of rods vs cones. Note the absence of rods in the center and the absence of both about 15° away from the the center toward the nose where the optic nerve passes.


At first glance the tendency would be to pick the hue of red at which we are most sensitive (566nm) which would make sense except for the real reason: we don't want to involve the rods. The reason is the rods share the neural pathways with the cones so that you have this fuzzy image overriding the detailed one. This effect disappears at slightly higher mesopic levels which is why white is a good choice for most tasks. Many people look at the numbers for sensitivity for rods and cones and forget that in most cases the numbers have been adjusted so that rod peek sensitive matches cone peak. Rods are in fact sensitive well into the infrared (not too useful except to know that light you can barely sense can adversely impact your night vision). The key then is finding a hue that we can have at a high enough intensity that we can see the detail we need without activating our rods to the point were they obscure that detail. Most source say this should be nothing shorter than 650nm. Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes.


Conclusions:

No matter what your color choice it must be fully adjustable for intensity.
If you need the fastest dark adaptation recovery and can adjust to the limitations, or everyone in your group is using night vision equipment then blue-green.
If you must see detail (reading a star chart, or instrument settings) and can lose peripheral vision (see note 1), then a very long wavelength red at a very low level. Red really only has an advantage at very low levels (were the night blind spot is very obvious).
A general walking around light so that you don't trip over the tripod, knock over equipment or bump into people, then blue-green with enough red added to get rid of the night blind spot, or maybe just use white. Blue-green at higher brightness also works very well and at a lower intensity than white.
If you need to see color and detail then likely the best choice is the dimmest white light for the shortest amount of time.
If you are in the military you must follow their rules; hopefully they will have a good course in unassisted night vision.
If you are a pilot and say you only fly in the day, you should be aware of the problems of night vision and should consider a basic (ground) course in night flying.
If you wonder why no one else has drawn these conclusions look at the dashboard of most cars. The markings are large, the pointers are large and an orange-red (a compromise, for certain "color blind" persons) and at night it is edge lit with blue-green filtered fully intensity adjustable light.
For Best night vision:
Be sure you are getting enough vitamin A or its precursor beta-carotene in your diet (needed for the visual purple).
Green leafy stuff is best followed by vegetables that have an orange color. Yes that includes carrots but spinach or dark leaf lettuce are better. It is possible to get too much vitamin A especially as a supplement.
Keep up your general health. Smoking is also very bad for night vision, as are most illegal drugs and some prescription drugs.
Keep you blood sugar level as even as possible. No meal skipping. Six small meals are better than three large meals. For carbohydrates favor starches (potatoes, rice,and bread) over simple sugars (sweets, alcohol).
Use dark neutral gray sunglasses, that pass no more that 15% in full sun, when outside during the day.
True night blindness is rare. Most of what people call night blindness is either a lack of vitamin A in the diet or a failure to understand the night blind spot.

Cataracts, even minor ones, increase the effects of glare at night and the eye's lens does yellow and passes less light as we age which may contribute to what some call night blindness.


Note: The red filtered light at the intensity most people use is likely decreasing night vision much more than a properly dimmed white or blue-green light would!


Note: There are day blind spots also but are in a different position in each eye so are less of a problem.


Note: Blue-green (also called cyan, turquoise, teal and other names) as used here is NOT the combination of two colors but is a single particular hue. I use the most common name for that hue

Interesting article Fanie.

But not much to be concerned. The common wheelhouse has so many different coloured LED´s on the nav equipment, you´ll have always a nice mix of colours.
And more than the nav instruments one should´nt have at night.

(ah, yes, on a sailing boat, I could imagine some people like to have the saloon illuminated a bit)

[Fanie]

Well, it seems we can get away el cheapo by using the existing lighting and just keep it as low as possible.

I'll keep the red ones for mob life jacket flashers. You cannot believe how bright these are...