New to the site here, so first question: I recently purchased a new Crestliner VT18 aluminum bass boat. It is fitted with the new Mercury 115 Pro XS 4 stroke motor. The dealer placed the motor in the second hole from the top, they said they found that hole worked the best, and when I asked, they said it was not recommended to add a jack plate. After having the boat out on the water, there a few things I've noticed. One, when I trim this boat, I can ONLY do it with a very small adjustment. Small bumps on the trim switch seem to have a major influence on the boat. Just a little too high and the motor cavitates. I can trim the motor, get the boat on plane and everything seems fine, until I go into a sharp bend of the river, or decide to turn suddenly, then it cavitates. Should I move the motor to a different hole, and what is everyone's opinion on a jack plate on an aluminum boat?