During World War I, the British and Americans faced a serious threat from German U-boats, which were sinking allied shipping at a dangerous rate. All attempts to camouflage ships at sea had failed, as the appearance of the sea and sky are always changing. Any color scheme that was concealing in one situation was conspicuous in others. A British artist and naval officer, Norman Wilkinson, promoted a new camouflage scheme. Instead of trying to conceal the ship, it simply broke up its lines and made it more difficult for the U-boat captain to determine the ship's course. The British called this camouflage scheme "Dazzle Painting." The Americans called it "Razzle Dazzle."