Wednesday, March 22, 2006

Submarines: "Britannic" Blue Advantages

HMS Torbay has a blue silhouette as she becomes even more stealthy in her ocean patrols. The Britannic blue color (unofficially, Steely Blue) softens otherwise sharp outlines of a black submarine making it up to twice as difficult to detect. The added stealth was prompted by shifts from North Atlantic operations, traditional for UK subs, to the brighter seas of the Middle East and Indian Ocean in the War on Terror.

Selection of the short, sea cadet wavelegth suggests several technical advantages, not including making other navies "blue with envy." Terry Goodship, chairman of the Submariners' International Association said: 'All submarines in the Med used to be blue. ... It is only in the very dark waters that we need to have the submarines painted black.'

Some Navy and Submarine History
Submarines have historically employed camouflage to blend in with operating background, including white for arctic waters and gray shades for various ocean areas. Shown above with HMS Torbay is the USS O-16 (SS-77) with its WW1 surface camouflage circa 1917. The U.S. Navy began experiments in the late 1930s to develop camouflage paints and applications, first publishing the results in January 1941. By 1944, there was a shortage of blue pigments. USN paint schemes had become more regimented by this time and quite a bit of blue was being used, to make mixtures of gray.

Eventually, all navies adopted versions of the U.S. Navy's submarine black. By the treacherous Cold War's end, not just any black, however.

Advantages of Blue (technical and Political)
Politically, black has always been associated with evil, and mystery, whereas blue is associated with masculinity and loyalty. So, will the U.S. follow suit if the UK gets good results?
Who manufactures the pigment?

Technically, color is more complicated, but there are some modern wrinkles to keep in mind beyond perceptions to the naked eye:

First, the human brain does not simply analyze wavelengths of incoming light detected by the eye to perceive color. Too many hues are visually discernable for that alone. For example, an object will be perceived as yellow if it reflects primarily yellow light. Yet, if it reflects not one photon of yellow light but reflects red and green light equally, it will still be perceived as yellow. Visible blue light has a wavelength of around 475 nm. Because blue wavelengths are shorter than most in the visible spectrum, they are scattered reltively well at the molecular level. This you recall, causes the sky to appear blue.

Secondly, neither blue or red wavelengths contribute strongly to luminosity ( intensity).

Finally, we all know detection of the submarine menace is not left to the naked eye by any sophisticated foe. How do satellites and computers see? Digitally, of course. And here is something to well remember (bold added): "Black doesn't reflect light, and white reflects all colors. On the other hand, if you are talking to someone like me who deals with generating colors on a computer screen, black and white are exactly the same color, one is just brighter than the other." - Eric Tolman, Computer Scientist

Challenge Question
Click on the above photograph for enlargement. See the pennant being flown by the O-16?
Identify it by name and site your source. (HINT: Better photos of the pennant in this era are available online). Have fun.


At 22 March, 2006 17:32, Anonymous Anonymous said...

More interesting is the bulge on the port side of the fin that should have been covered

At 22 March, 2006 20:35, Anonymous Anonymous said...

Submarine Operating in Area. (which says that the pennant was made of metal when flown on a submarine - I suppose that this was so they could just leave it in place when they submerged, and thus have it displayed the moment they broke the surface)

RM1(SS) (ret)

At 22 March, 2006 21:29, Blogger Vigilis said...

spearfish, others of the British realm have noted your observation in a RN chat room. You will get no argument, here. Pray tell, what is it?

At 22 March, 2006 21:31, Blogger Vigilis said...

RM1 (SS) anonymous- you may want to come up with an identifying flag name before someone else.

Cheers, -Vigilis

At 23 March, 2006 09:11, Anonymous Anonymous said...

Vigilis,I was hoping you could tell me what you think it is!Another t-boat has got it -Trafalgar.At the fleet review in portsmouth last year the crew of Trafalgar were very careful to cover it after the skynews helicopter had flown past!

At 24 March, 2006 16:58, Blogger Vigilis said...

trr, would not recommend it unless you live somewhere the sun is scarce. But then, you are the chemical engineer, not me. -Vigilis


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