"Kill all uncessesary lights...."

[MarkQuinn]

Sorry for the off-topic post, but as I type this I am reading about midget submarines in WOLFPACK, have a war patrol going on in SHIII and have Das Boot playing in the next room. Yes, it is a U-Boot kind of night.

I figured this would be the best place to find an answer to my question.

Why does the commander in Das Boot order all unecessary lights turned off as they dive to escape the destroyer?

MQ

[CCIP]

Probably to 1) save electricity and 2) keep the crew more quiet and in one place (so they don't move around and make noise - you don't usually get up and start walking around if it's dark)

[AO1_AW_SW_USN]

Two reasons:

1. Turning off unnecessary lights helps conserve the precious energy stored in the battery.

2. Turning off/on the lights is a much better way to communicate to a submariner to secure for silent running, rather than using a very noisy interior communication announcement system between compartments.


In addition, it is believed by some that play this game that the bright white lights are switched to red to indicate the time of sunset. This is partially true.

Bright lights are switched to red at sunset to all hatches and watertight doors leading to weather decks (outside access to a ship or vessel). This is because red lights are much more difficult to spot at night rather then a bright white light, thus making the ship of vessel difficult to spot by unfriendly units. This is called "Darken Ship" in most of the world's Navies and it's practiced by all, even in peacetime.

[MarkQuinn]

Thank you both for your answers.

In addition, it is believed by some that play this game that the bright white lights are switched to red to indicate the time of sunset. This is partially true.

I'd watched a show about a modern US sub a long time ago (have since forgotten it) where the above explanation for the red lights was given: a sort of psychological effect for the crew so they do not feel they are living in perpetual daylight. The aspect of red light not traveling as far/being harder to spot also makes sense to me.

MQ

[Aqualung]

regarding use of red light in the evenings, I thought the main reason (and I cannot recall where I read this so am happy to admit this could well be wrong) for using red light was because it had less impact on your 'night vision' than white light. It takes the human eye quite some time to adjust to low light conditions which is why if we step out of a well lit room into a dark night it's very hard at first to see anything, but our eyes adjust if we stay out in the dark until we can see at least a little (save for in pitch darkness - the absence of any light, of course).

Once our eyes have adjusted to low light conditions, even a brief amount of white light (normal elecrtic lighting) will usually mean we have to go through the whole adjustment process again when back in the dark - only takes a few minutes, but thats a long time if your looking for enemy ships

Switching to red light in the evenings therefore makes it easier for the kaleun and crew to preserve their 'night vision' and spot things on the surface in the dark. In fact, I'm sure in one evening scene in Das Boot you can even see the Kaleun wearing darkened goggles on his head - which I assumed (if an accurate historical reflection) was to help him preserve maximum night vision.

Like I said, could be wrong. However, am pretty sure the above is accurate.

[donut]

Aqualung's correct #1 answer 100 Renoun

Red light is used to prevent night vision loss and to reduce the chance of being spotted.

But you may ask yourself, why red light, why not say Blue or Green. Well the simple fact is that red light is at the bottom of the visable light spectrum just befor it become infrared. Now infrared as every 1 knows is a light we cant see, we can feel it tho (called heat), but we cant see it. So if your using a visable light source thats damn close to a light source we cant see, what do you think happens. Our pupils expand of course to gather as much of this nearly none visable light into the retina so as our feeble brains can process it.

Blue light believe it or not is actualy the closest colour light to white light, so its of course no good, Green follows not to far behind.

Also of interest, when a match stick is struck onto the box and the immediate flaring that you get - thats visable on a good clear night to 1 mile. Now you can see why the red light's are always so dull, to even further reduce the Night vision loss and detection.

[jumpy]

oh yeah!
makes my 'puter room look like a knocking shop, but what the hell... made things seem easier on the bridge at night

[Overstear]

LOL

[STEED]

Originally Posted by jumpy

makes my 'puter room look like a knocking shop

I shall keep an eye on the news from the Midlands

Originally Posted by AO1_AW_SW_USN

This is called "Darken Ship" in most of the world's Navies and it's practiced by all, even in peacetime.

When I was in we called it "Rig For Red". It also works wonderfully well on surface ships, when you are moving in and out a lot.

[MikuliES]

It is still referred to as "Rig for Red" in 688 submarine control rooms and standard procedure for PD preparations at night and/or shallow water operations requiring the scopes up continously. It is done by the Messenger by order of the Chief of the Watch. It is not required if no scopes are up or the ship is not surfacing.

It is a night vision aid or atleast that is what is taught in the Periscope portion of the ESM training in Groton; although ...

... there are various areas of the boat with colored light capabilities: ex. the bridge trunk has red as well as all compartments leading into the control room, and the lighting in radio above the ESM interface panel may be rigged blue [though my XO found it hard to read black ink messages on paper bathed in blue and would frequently growl and flip on the bright whites upon entering.]

It was/and i suppose still is part of the messenger's job to rig the forward passageway/control room for sunset and sunrise ... which simply meant turning on/off the lights to the appropriate level depending on what depth the boat was at and what time of day.

As far as the Unterseeboots were concerned, taking down all unecessary lights while submerged was part of the procedure for rigging the boat for silent running, and/or deep submergence, or battlestations -- the theory being the less equipment running the better. It conserves power, makes less noise, and reduces chance of fire when taking damage. SUBs today will "power down unnecessary equipment" and "secure all unecessary evolutions".

[AO1_AW_SW_USN]

Well, I was recently discharged from the US Navy. I had to set a watch bill to my Division to ensure "Darken Ship" was set in all my spaces that all "Circle X-Ray" doors were secured and lights switched from white to red. I also had to ensure that the "Darken Ship" log was signed under my Division's name for the OOD (Officer of the Deck).

Yes, your night vision adjustment holds merit. I'm not denying that. But that's not the reason for switching to a red light at sunset for surface ships. The true purpose of "Darken Ship" was to reduce the emission of bright lights that radiated from the ship's weather decks.

I do admit, the Submariners (Bubbleheads) and their "Rig for Red" is different in most aspects.

[tycho102]

Originally Posted by Cdre Gibs

Red light is used to prevent night vision loss and to reduce the chance of being spotted.

But you may ask yourself, why red light, why not say Blue or Green. Well the simple fact is that red light is at the bottom of the visable light spectrum just befor it become infrared. Now infrared as every 1 knows is a light we cant see, we can feel it tho (called heat), but we cant see it. So if your using a visable light source thats damn close to a light source we cant see, what do you think happens. Our pupils expand of course to gather as much of this nearly none visable light into the retina so as our feeble brains can process it.

Blue light believe it or not is actualy the closest colour light to white light, so its of course no good, Green follows not to far behind.

Close.

Rhodopsin is the main pigment in the rods of your retina. Rods are designed to absorb low-level (low lux) light, but at a very poor resolution. Rhodopsin is purple, so it reflects mostly red and blue, and absorbs green most efficiently.

Years ago, this much retinal biochemistry was unknown. Emperical data showed that green required the least lux for a given resolving ability, with red and blue following. Red filters and lenses were more economical to make, and red is generally absorbed more efficiently by the majority of substances on our planet (namely water and chlorophyll), so red propagates less than blue or green.

However, we have since learned that it takes far less green light power, and our eyes have greater resolving power with green light, that most low-light operations have started using it. Night-vision goggles, backlit LCD displays, cockpits.

Red is still used on vehicles because of the propagation factor. Water in the atomsphere absorbs it very quickly; far more quickly than green or blue. Blue and violet are the last light waves to be filtered out in the deep ocean (violet extends to nearly 50 meters depth).

[Redwine]

Interesting topic.....

Which is the function or the objective of the Blue lights ?

If you look at the das Boot Movie, they had White, Red and Blue lights.