I have a 21’ rinker v bottom open bow. Just bought a new cover 600D waterproof , trailerable. It does well in warm weather but doesnt look like it will do well in winter. Im going to build a 2x4 frame to support cover for winter, but Im thinking of putting a waterproof tarp over the cover as well to make it easier for snow to shed off. does anyone else do this? Is it a bad idea? A tarp costs $30. I know there are products like transhield, but I have reached my budget limit for the season. After winterizing the boat a $200 winter cover is not an option.