Dazzle camouflage was developed in World War 1 by the painter Norman Wilkinson, and was intended to confuse U-boats to such an extent the would be unable to fire torpedoes at the ships.
In order to attack a ship with a torpedo the U-boats needed information such as the ships range, heading, speed and type. The dazzle camouflage made it very difficult for a U-boat to identify the bow and other important features used to calculate the required information.
These weren’t just random patterns either, Wilkinson set up ship models on a turntable and viewed them through a mock up periscope, in light and dark conditions to test out if the direction of the model could be ascertained.
A team of female painters worked on the designs and would paint the specific pattern as an actual painting which would then be sent to the shipyards to be copied onto the ships.