0
Here's the short answer: to preserve the night-vision of the submarine's crew, while retaining adequate color and depth-perception abilities.
The long answer? Well, to understand that, let me take you back, just before World War I, when early submarines were starting to come into their own.
Back then, all military vessels--surface and submerged--relied on red-colored lighting for night operations. The theory, at the time, was that red-hued light only saturated the red photo-receptors of a person's eyes, thus leaving the green and blue receptors unaffected. Hence, all-important "night-vision" could be preserved better by stimulating only *one* of the three photo-receptors (humans can see red, green, and blue, and have receptors for each of these three "primary" colors). In addition, red had the advantage of a high-frequency wavelength (about 560-570 nm). When coupled with a low-powered intensity of illumination (through lower wattage, typically 4-6 W; what your standard incandescent "night-light" puts out), the light effectively "died-out"; it was hard to detect from long distances. Perfect for surface-going ships.
But, how did this make its way to the world of the submarine?
Remember, early submarines were really not much more than surface-going small frigates (some would say, using the British term, more like "corvettes") that *could* submerge under water. Back then, submarines did the majority of their fighting "above-the-beam"; from a surfaced position. That's why all those old WWI-WWII era subs have huge deck guns--you're not going to fire that thing from underwater!
Instead, the purpose of a submarine was to stealthily sneak up on an enemy contact, quickly surface, fire off it's deck guns, and submerge before it could be fired upon. (Although torpedoes could be used, they were--for the time--fraught with unreliability, were expensive, and required the boat to remain on-station until impact--due to their cable-operated guidance--thus rendering a submarine highly vulnerable to counter-attack.) Thus, the deck gun was the most favored means of primary attack.
Most submarine surface attacks were carried out at night (I don't care what's depicted in U-571, that was a completely different, highly-desperate situation). Thus, transitioning from the enclosed, controlled conditions inside the boat to the exposed, uncontrolled conditions *outside* the boat had to be done as quickly as possible. As the ship came to Battle Stations, and subsequently surfaced, the Chief of the Boat would "rig for red," dimming (or extinguishing) all work lights, and lighting the red lights, so as to prepare the men for going topside, into the night. Remember what I said, a few paragraphs ago? By saturating the men's eyes with red-colored light, their blue and green "night-vision" perception was thus unaffected, making "recovery time" once topside much quicker!
In fact, this tradition is still used by submariners, to this day. When a sub surfaces, the lights are switched to red (as accurately portrayed aboard the USS Dallas in The Hunt for Red October). As Cpt. Mancuso and his XO go up to the weather bridge, the lights switch to red--the holdover from the old submariner days!
So, what's with the funky bluish-green lights, you ask? It has to do with two developments, namely: better understanding of how the human eye works, and advancements in computer-display technologies.
First-off, the human eye. By the mid-60's, scientists had discovered that red-light saturation actually *decreased* night-vision, to some extent. It wasn't necessarily the hue of the light that affects night-vision (though that fact is still debated), but rather the intensity of illumination. See, red-hued light requires almost *twice* as much illumination to provide the same candle-power as lower-frequency (420-460 nm) blue-hued light. Thus, red-light is prone to induce more glare, and will negatively affect the cones (photo-receptors) of the eye. Blue-green light at a *lower* illumination is actually better, providing more color "information" per degree of illumination.
Which leads to the second development...
Red light kills depth and color perception. Sonar operators--who relied not only on their well-trained ears, but also their well-trained *eyes* to interpret the sonar plot)--were reporting trouble reading their spectral plots in the intense red light (coincidentally, most sonar plots are now green-and-blue, and sonar shacks are *always* rigged in blue lighting). The Navy conducted many studies and tests, and found out--sure enough--that blue light would actually be better for *modern* submariners. Since they hardly go topside, now, to fire their armaments, the whole "preserving night-vision" mechanism is unnecessary. Instead, accurate color and depth-perception, especially when translating instrument output, is paramount. Again, using The Hunt for Red October, as the Dallas goes to Battle Stations, the blue lamps are switched on!
Add your answer:
Earn +20 pts
Material used to build first submarine?
Wood was used to make the first submarine
Why was a blue light used by the navy?
white light carries a long distance, especially at night. Using blue lenses on lights decreases the distance light can be seen, helping to conceal position.
Is a U boat a submarine?
A U-boat was a submarine used by Germany in World War 1 and World War 2.
Who created the submarine that was called turtle?
David Bushnell created and used the Turtle
What was the name of the first American submarine?
Techically, that would be the U.S. Navy's first submarine, USS S-1 (SS-105) , built by John Phillip Holland. Though the first submarine that was used in combat, David Bushnell's Turtle (Revolutionary War), the U.S. wasn't in fact a country at that time.The Confederate submarine H.L. Hunley was also not technically an American submarine, effectively being used by the Confederate Army (manned by Confederate sailors), but it was never a commissioned vessel in any navy.
What is the purpose of the red lights used in submarine control rooms?
Red light is supposed to be easier for the eyes to transition to darkness. Red lights are also used on the bridge or pilot house of boats and ships. It does allow you to regain your night vision quicker.
What color are the lights used to outline taxiways?
yellow and black
Is it illegal to have blue cab roof lights?
In the United States it is illegal to have blue lights anywhere on a vehicle unless the vehicle is used by law enforcement personnel.
Is there a blue light on a traffic light?
No, traffic lights typically have red, yellow, and green lights. Blue lights are not commonly used on traffic signals because they could be confused with emergency vehicles.
When were blue lights first used on policed cars in the us?
Blue lights were first used on a police car in the 1980's. This was in the United States.
What is the purpose of definity?
The purpose of definity can vary depending on what the context of the situation in which it is being used. The main and most common purpose of definity is to define something, like with lights.
Material used to build first submarine?
Wood was used to make the first submarine
What is the purpose of rope lights?
The purpose of rope lights is for decoration. Then can be used indoor or outdoor to light up any area. They easily be bent or twisted into any shape and or hang on pole or fence with little or no effort.
Why are taxiway lights blue and runway lights white?
White: Probably because white is the brightest color (no colors are filtered out of white light) and the main runway lights are the most important lights for a pilot to see in bad weather. Blue: Probably because red is typically used as a warning color (and sometimes direction), and green is sometimes used to indicate direction, blue was available to use for taxiways and was not distracting.
A sentence with submarine in it?
A submarine is only used under water.
How was the submarine used?
they were used in wars
How is the word submarine used in a simple sentence?
The submarine is under water.
