I thought the dazzle camo scheme wasn't meant to make the boats harder to spot, but rather, to make it more difficult for the enemy gunners/u-boats to determine it's course, speed and length. From what I've read so far, it was rather successful at accomplishing this with it's British innovators and was therefore adopted by the U.S. Navy. Of course, the advent of gun laying radar meant the advent of camo schemes designed to make the vessel harder to see.
