Is TotalBoat Halcyon a water-based polyurethane? Eric Boudreau November 25, 2020 19:47 Updated TotalBoat Halcyon varnish is a water-based polyurethane coating which was designed for superior performance, making it suitable for marine applications. Related articles Can TotalBoat Halcyon be applied over TotalBoat Wood Sealer? Will TotalBoat TotalStrip remove TotalBoat Halcyon? Can TotalBoat Halcyon be applied over linseed oil or tung oil? Can TotalBoat Halcyon be applied over shellac? Which varnish should I use? Comments 0 comments Please sign in to leave a comment.