Disclaimer: My facts came from viewing “Das Boot”, which was perhaps the best submarine film ever made, but fictional nonetheless.
So when I was watching the film, when they were preparing to attack, the bridge was appropriately swathed in red, as we have all seen in Navy movies. But, the next scene shows them switching the white lights in the forward torpedo room to blue.
Why would the torpedomen get blue, while the bridge was in red?
If they need to see their work, leave the white lights on. If the white light would bleed into the other parts of the ship, turn on red lights instead.
That was for the bridge crew, so that they could dark-adapt their eyes so as to see the enemy better. The guys in the other compartments needed bright lights to do their job.
I wonder if it might have to do with the torpedo tubes themselves. Water absorbs blue light, so it’s less likely to be noticed from above in case of a leak in the outer seal while they’re loading torpedoes, which is probably quite handy in case there are planes and destroyers in the area.
Edit: But then, that should work even better with red light at depth and make no difference near the surface, come to think of it. All right, I’ve got nothing.
I’m not a submariner, but it was my understanding that red made it difficult to see certain bits that were in the engine room and torpedo room. They didn’t want to just use white because (a) they want some indication that the ship is running in combat conditions so that the sailors don’t need to wait for orders to rig the sub’s equipment a certain way and (b) blue, according to WWII era understanding of vision still only saturated some of the eye’s color sensors, which meant that the sailors would still have some night vision if it became necessary.
I have a friend who used to be a submariner. If we don’t get a more definitive answer by Monday, I’ll ask him.
I found a mention here that states blue lights indicate submerging, but there’s no cite for it that I can find and I’m not sure how much of an expert “Anonymous B” is. Still, it does make a certain kind of sense that crewmen would need to be extra attentive during a dive.
It’s like red alert in star trek - visual cues can be useful to get people into the appropriate demeanor for the conditions. red ain’t so hot for seeing everything. so why not blue?
I have no idea how much it applies — if at all — to the question at hand, but I recall reading the following in a (fictional) book on submarining during the Korean War:[ul]
[li]There was one person who decided that red lights were appropriate for nighttime conditions.[/li][li]There was another person who decided that red was the appropriate color for indicating important information on charts, gauges, etc.[/li][li]The two obviously never met, much less discussed their determinations.[/li][/ul]Whenever someone was about to use a “bright” light to check a chart or light a cigarette, he would tell everyone in the vicinity to close their eyes. At one point the protagonist forgot to rescind the order, and by the time he did the boat had lost depth control and was very near to crush depth.
And I can attest to the color issues of using red light…
I remember one bewildering moment on the ship when, while bathed in red light, I tore open a box of Good 'n Plenty licorice candy and poured the contents into my hand. My first reaction was “Wow, a whole box full of white Good 'n Plenty”
…Then I realized that the magenta/purplish ones looked exactly like the white ones under the red light.
From my understanding, the point of using red light on the bridge at all is to allow the officer manning the periscope to retain his night vision. If the electrical systems go on a sub, no amount of night vision is going to do anything at all, because everything will be perfectly pitch black.