Measure the region to be wrapped. You may want to do this step with the boat out of the water. The shrink wrap will require covering the entire top of the marine, including extra height for windshields and other protrusions down to a region on the hull below the rub rail.
https://shrinkwrappingnz.blogspot.com/2017/01/how-to-install-shrink-wrap-on-marine.html