KINGSTON, New York — Behind the diesel-powered Rip Van Winkle party boat, across from Mathilda, the decommissioned 19th-century tugboat, and about 1,000 yards upriver from the rusted husk of a retired New York City hospital barge named the Lila Acheson Wallace, you will find the Solaris, pitching softly on the placid Rondout Creek, a tributary of the Hudson River. It’s an elegant boat, white and cream-colored with wooden accents, its spotless 45-foot hull a stark contrast to some of the older ve