Monday, September 14, 2009

Dazzle Camoflage

In Lynda Barry's perpetually amazing book Cruddy, the Navy-trained father repeatedly speaks of "dazzle camoflage" as a way to cover up his crimes - hacking up a body to cover up that she was shot first, and filling a trailer with freshly slaughtered deer meat in order to conceal the human blood already in it.

Prior to his creative license taken with the term, Dazzle Camoflage was a means to help ships in World War I and World War II confuse the enemy. According to Wikipedia:

At first glance it seems unlikely camouflage, drawing attention to the ship rather than hiding it, but this technique was developed after the Allied Navy's failure to develop effective means to disguise ships in all weather.

Dazzle did not conceal the ship but made it difficult for the enemy to estimate its speed and heading. The idea was to disrupt the visual rangefinders used for naval artillery. Its purpose was confusion rather than concealment. An observer would find it difficult to know exactly whether the stern or the bow is in view; and it would be equally difficult to estimate whether the observed vessel is moving towards or away from the observer's position.

The rangefinders were based on the co-incidence principle with an optical mechanism, operated by a human to compute the range. The operator adjusted the mechanism until two half-images of the target lined up in a complete picture. Dazzle was intended to make that hard because clashing patterns looked abnormal even when the two halves were aligned. This became more important when submarine periscopes included similar rangefinders. As an additional feature, the dazzle pattern usually included a false bow wave to make estimation of the ship's speed difficult.

""There is required for the composition of a great commander not only massive common sense and reasoning power, not only imagination, but also an element of legerdemain, an original and sinister touch, which leaves the enemy puzzled as well as beaten." - Sir Winston Churchill, The World Crisis, 1923.

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