for 800 bucks I'd suggest buying a used deep vee style gasser, or building a gasser deep vee, at least 48inches long for running in ocean waves, I wouldnt run it in more then 6-8 inch waves though, also saltwater is a killer on electronics and corrodes very quickly...and as for about a third of the boats overall length from the transom is about were it should be...have you found pictures of anything that you like, that would probablly help everyone here to help you out a little better...get things going in the right direction