jet-o-vater and place diverters do the same job but a different animal. it lets you trim the jet nozzle, changing the attitude and ride of the boat. in the full up position, it is what gives jetboats the ability to throw that big roostertail behind it.
i see youre pretty new around here (welcome), most of my time spent here is searching, and reading reading reading. theres tons of info, the search is your friend