How come some boats you sit on the right side to drive like on all Sea Rays that we built at the Phoenix plant and my neighbors bayliner etc. and most jet boats are left side drive? My 16 year old son asked my this question and I did not notice but now I am wondering. 
I have several answers, I think most of them are correct. The best one is that most if not all jet boats are lake only use boats (or river) and the navigation rules for the lake are much different than for a harbor or ocean, all the lakes I have ever been to are counter clockwise putting the driver on the inside if on the left...
I have also heard the counteraction of rotational force, but I call BS.
It would be rare to find a low profile jetboat on the East coat and also rare to find a left hand drive, so lets just call it a California thing...

GT