I have a 2005 Coleman Niagara. Lovely, especially the open roominess and full bathroom for 2 am. Otherwise, don't use the electric or water hookups. Bought it used 5 years ago, but wasn't for a couple of years realized the pullout canvas was leaking onto the bed corners and the OSB was starting to get punky in the outer corners. Put a 1 ft strip of varnish around the OSB borders that stopped the deterioration without compromising its breathability. Sealed every stitch hole (I swear there are several thousand stitches!) and 303'ed the entire canvas, and finally sealed a couple of pinholes in the vinyl. Stopped the leaking. Then last August, a puddle on the varnish from water running down the U tube (I paper towel to trace the leak) where roof drainage runs down the canvas. Problem is the 303 doesn't last long and really should be applied every year or two. Big issue with the 303, besides cost, is it can't get on the vinyl. With the frequent applications, I'm guaranteed to miss a vinyl spill. 1- Does anyone know what 303 does to vinyl? 2- Is there a 303 replacement that is OK to vinyl? If there is an issue with breathability, looks, etc., I can limit its application to the pullouts where the roof drainage runs down the canvas. Thanks to anyone with ideas.