I have a 1998 sylvan deck boat that when I bought it had a jack plate with a 90 hp mariner , my question is does it really need to be there ? Have no idea why the previous owner put it on. The reason I ask is when I use the trim if I move it up just a little like 3 to 5 degrees it seams to cavitation. I have to keep it tucked down . Did check the distance on the cavitation plate to bottom of the boat and its bout an inch below. Also it is a tri hull , which I've never owned before so I'm just not us to it. Any ideas ? Or I just might take it off , also it sticks out about 10 to 12 inchs off the transom.