Vessel #2 traveling north of the Manson Bay marina on Lake Chelan at approximately 1230 hours.  Vessel #1 traveling directly behinf #2.  According to the operator of vessel #1, he was jumping the wake of vessel #2 and at one point a wave pushed his vessel/jet ski inot the port side, stern of vessel #2.  THe eroaptor of vessel #1 said he was then thrown into the cab of vessel #2.