This scheme was designed to be disruptive, thereby confusing enemy gunners.
It consisted of black and white stripes on all vertical surfaces, with light blue-greyish counter shading. This scheme was not used on any boats in action.
Zebra Scheme (click for larger view)
Drawing courtesy of Andreas Hanke, Germany
However, a modification of this scheme was applied to a number of Elco 80 foot PT-103 Class boats, PTs 163 - 174. This modification utilized an yellowish green in lieu of the white stripes. The scheme proved to be unsuccessful and was painted over with a more appropriate scheme.
A squadron (Squadron 15) of Higgins 78 foot PT-71 Class boats, was deployed to the Mediterranean with the variation of this scheme utilizing the black and white stripes.
The bottoms of all of these boats were all Copperoyd.
Further discussion on the Adaptor Scheme (Zebra Scheme)
and photos of PT-174 with and with and without