Snap Extenders for Old Canvas
Sunbrella does not shrink. That is the mantra, and for covers and dodger that are left in place, it seems to be the true. It stretches a little when wet, and so long as it is maintained under tension while it dries, it retains it shape. So says Sunbrella. While this seems true for tensioned cloth (our dodger still fits) and it hardly matters for a sail cover, our real world experience with removable Sunbrella window covers has been different, shrinking as much as 5 percent over a period of years. The problem, no doubt, is that these are worst case scenario, repeatedly removed while still wet with dew and allowed to dry. The end result was that the covers became difficult to install and some of the snaps were being ripped out by the excessive tension.
While not pretty, a simple solution is snap extenders. Simply a short strip of polyester cloth with a male and female snap set in the ends, a handful of these can make the most stubborn cover easy to install. They are available pre-made in standard lengths, or you can make you own using hammer-on snaps and the material of your choice, including webbing and leather.