SailNet Community banner
1 - 19 of 19 Posts

·
Registered
Joined
·
188 Posts
Discussion Starter · #1 ·
Looking into updating my mast headlight and deck light to LED. Misea/Signalmate has a combination unit with either a red or white deck light. Have not seen the red offered by others but seems to me a very good idea. Marinebeam has a nice and much less expensive unit with white only for the deck light. Any experience with red deck lights?

BTW - I installed a Signalmate (was called Kimberlite then) LED stern light in 2009. This spring noticed it was half full of water. They were very good about warranty replacement.
 

·
Once known as Hartley18
Joined
·
5,179 Posts
One issue I can think of with a red deck light is the possibility of it being mistaken for a nav light ie. it wouldn't be legal to use it under way, which is when you're most likely to want it so's not to affect night vision.

It couldn't be used as an anchor light either.. so, although it sounds like a great idea, it probably isn't. :)
 

·
Registered
Joined
·
5,072 Posts
Red, Green, Yellow, Purple doesnt make a difference, its the intensity that is the bane of night vision.
Id opt for the white deck light ... and then put a rheostat on it to control the amount of 'brightness'.
 

·
Registered
Joined
·
511 Posts
Red, Green, Yellow, Purple doesnt make a difference, its the intensity that is the bane of night vision.
Id opt for the white deck light ... and then put a rheostat on it to control the amount of 'brightness'.
Intensity is vital. A light has to be very dim to preserve most of our night vision, but our rod receptors are very insensitive to red. This means it if you want to see some detail and preserve scotopic vision colour is important. Red is the only option.
 

·
██▓▓▒▒░&
Joined
·
13,641 Posts
"Red is the only option. "
Old school, and proven obsolete. The intensity of the light counts for as much or more than the color does. Since our eyes are many many times more sensitive to a yellow-green color, a dim amber can be better than red. And with LED options, it is so much simpler to restrict colors, as opposed to trying to make expensive glass filters or colored bulbs.
Vision and spectrum can get quite complicated. Like avoiding the use of blue lights, which are all the rage for a while now, because the eye doesn't focus well with blue light.
And then there's a little problem with yellow, because our eyes can't actually detect yellow light. Our eyes only sense red, green, and blue. Our brains deduce "yellow" from the green/blue balance, and since that deduction is a very subjective process, there's no way to tell if the "yellow" you see is the "canary" I see.
But red, versus dim white, dim green, or dim anything else? There's been a lot of discussion and measurement on that in the last 20 years, and red is no longer king. What do they say? No one ever got fired for hiring IBM? Or for choosing red for night lighting. Just makes it tradition.
 

·
Don't call me a "senior"!
Joined
·
968 Posts
Once your eyes get used to it you can see pretty clearly in incredibly dim light. I would just use as dim a white light as will do the job. I think I read somewhere that the whole red light thing comes from the use of red "safelights" in darkrooms when printing black and white photos.
 

·
██▓▓▒▒░&
Joined
·
13,641 Posts
"the whole red light thing comes from the use of red "safelights" in darkrooms when printing black and white photos. "
Not for a long time. Red safelights were needed for orthochromatic films, but for many decades "photographic" films and paper are panchromatic and what is called an "orange amber" or similar yellow-green safelight has been used. Red has only been used for special high contrast graphic arts media, for decades and decades now. Originally, GE actually made red safelight bulbs, using red glass. No filters or paint were involved. I'd bet that it was simpler to make red glass than to try blending odd amber colors. (There are a number of specific specs for safelight colors.)
It is generally easier to work in a darkroom with "amber" safelights, you can see much better than with the red ones, even when the same bulb and fixture are being used.

Since red was the military standard for many years, it was used in the civilian world for night lighting.

Perhaps not coincidentally, I've read that most terminal predators (i.e. humans) mainly see the color red when they see blood. Or poisonous plants. I'm told that simply switching to red lights also tickles the fight-or-flight reaction, presumably because red usually meant blood, so switching to red night lights might also carry something of an adrenalin boost. Which would work out just fine for the military and night combat operations.
 

·
Registered
Joined
·
511 Posts
"the whole red light thing comes from the use of red "safelights" in darkrooms when printing black and white photos. "
No it has nothing to do red lights used in darkrooms, although the principal is the same. Our Rod receptors are very insensitive to red light like some types of photographic film. Our cone receptors work much better with red so using red light our cones still function, but our rods remain dark adapted. This is scotopic and photopic spectral sensitivity curves. You can see the shift in sensitivity which can exploited with red light. Wavelengths above 650nm cannot be seen by our rod receptors so we can use such wavelengths without effecting their sensitivity.

Red is only useful if we want to maintain a very high level of dark adaptation. It is difficult to work with and pointless if the environment and time needed to obtain near full dark adaptation is not available. But a yacht sailing at night is such an environment at least on some occasions.
 

Attachments

·
Registered
Joined
·
23 Posts
Back in the day, just after the Vikings, the aircraft carriers I was on would use red flood lights for the flight deck and we were only allowed to used blue lensed flashlights. We also used single "D" cell flashlights (think match light) clipped to our vests in the event we went over the side. Maybe things have changed. :)
 

·
Registered
Joined
·
511 Posts
Maybe things have changed. :)
Yes things have changed. There is so much information from sophisticated radar and sonar in modern ships and aircraft that maintaining a high level of dark adaptation is not practical so red light light has become largely irrelevant.

This also, sometimes, applies to our sized vessels when using chartplotter/radar etc, but there are times on our smaller vessels when high levels of dark adaptation are needed, such as entering an anchorage at night and trying to spot fishing floats etc.

Unfortunately if use any colour other than red to see detail, such as reading the pilot book, if the light is bright enough to read text you have almost completely bleached out your rod function. You will still retain some dark adaption from your cone function, but to regain full dark adaptation will take at least a further 15mins.

You can overcome this assigning another crew member to retain full dark adaptation, or close one eye and only bleach out the receptors in one retina. However, because Rods cannot respond to red light this colour light can be used to see detail (such as reading) without bleaching out the rod receptors.

Red light is very uncomfortable to use, it also removes some coloured detail, but the physiology of eye is such that it is the only light source that seen by our cone receptors and not our rod receptors. In our bright world this has very limited application, but on sailboat at night is one of those situations.
 

·
Registered
Joined
·
5,111 Posts
Looking into updating my mast headlight and deck light to LED. Misea/Signalmate has a combination unit with either a red or white deck light. Have not seen the red offered by others but seems to me a very good idea. Marinebeam has a nice and much less expensive unit with white only for the deck light. Any experience with red deck lights?
I'm using an Aqua Signal Series 41 Steaming/foredeck combo, nice unit, though perhaps a bit 'bulky' on a boat as small as mine... Not a problem, though, I like 'oversized' when it comes to running lights :) Seems considerably less expensive than the Misea, they occasionally show up on eBay, I found mine at a consignment shop for about $75...



They come with a standard "tractor light", which I swapped out for an LED about a year ago... Turned out to be a HUGE improvement over the original incandescent or halogen, whatever it was...

I, too, was thinking about going to a colored lens, red or yellow... But I went with a soft white, which is almost more of a very pale yellow, and for me it turned out to be the right choice... (If you do decide to go this route, it really pays to shop around, prices for these replacement LED tractor lamps are all over the place, I think I scored mine on eBay for under $30. )

While the LED appears to be a bit less directional or 'intense', it seems to offer far greater illumination in a much greater arc surrounding the boat... Seems to be a 'softer' light than the previous incandescent, which surprised me a bit, but I think might translate to a bit less of a loss of night vision. The greater arc of illumination is a big advantage in a foredeck light, IMHO, and could be critical in an emergency situation such as a MOB recovery. I first noticed the difference coming back into my lagoon late at night, a narrow, twisting waterway that is getting narrower each year, as more residents add boat lifts, jet ski docks and other projections that further encroach on the canal. The LED does a far superior job of illuminating the sides of my lagoon, and thus would be of great benefit in situations like entering a slip in a marina, or weaving thru a crowded mooring field in the dark. Not too long ago I had crossed Albemarle Sound late at night to beat some weather, and was looking to anchor up just outside of the channel for the night. Problem with that area, it's littered with crab pots, and the foredeck light on the boat I was running was really lame. A light like mine would have been very beneficial in that situation...

For spreader or deck lights, I think the concern over the loss of night vision is a bit overstated, and I really don't think I'm suffering much of a loss of night vision at all with the light I'm using now... And, in many instances like those I've mentioned above, you might be most likely to be using a foredeck light when anchoring, coming into a dock, etc - when you're basically 'finished' for the night, anyway...
 

·
Registered
Joined
·
178 Posts
Intensity is vital. A light has to be very dim to preserve most of our night vision, but our rod receptors are very insensitive to red. This means it if you want to see some detail and preserve scotopic vision colour is important. Red is the only option.
I wonder if charts are made "red-light readable" like topos used by the Army. Without that characteristic, map features like roads disappear under red light.

Here is a discussion about light color and reading maps/charts:

Map Light color choice
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top