If I remember right. Drake was "driving" the canoe and Cousin D was standing in the back playing King of the Mountain {or King of Something, the Canoe???} when the wave runner came around and he lost his balance and abandoned ship.
D then tried to make a get away but it didn't work. 
D then got a tow from G "the model" and 
then coasted into shore where he met up with Cousin D after his long swim back. 
Oh summer fun... 