Like Ross siad, it will bond with mild sanding.
The life span of the paint is the question. If you want to dress up the boat fast, sand and paint. If you are going to own the boat more than two years, remove the vinyl. Most vinyl lettering is time dated. e.g. 2 year, 5 year, 10 year. That is for the color in the lettering.Who knows how long the bond will last in UV conditions. So, your north/south location plays into the UV factor. Your future intensions for owning the boat also plays a part. Short term, sand and paint. Long term, remove prep and paint or maybe another vinyl stripe.r.w.landau