Is there any way to restore a cedar-strip canoe that has developed gaps after being out of the water for years?
A canoe may look gappy, but that doesn’t mean it will take on water like a post-iceberg Titanic. Wooden boats gain and lose moisture, so if you get your canoe wet, the gaps should disappear as the wood absorbs water and expands. Soak the canoe for a day, then bail it out and let it dry before taking it for a paddle. If you come back with a cup or two of water in the bottom, no big deal. If it’s leaking any more than that, you should sand and re-coat with a high-grade oil-based varnish. The varnish will wick its way into the cracks and help seal them.
If the majority of the varnish looks fine, there’s no need to take the boat down to bare wood. Build up small damaged areas, lightly sand the surface, then use one full coat to blend.
Unfortunately, if the canoe is very badly dried out, it may need to be stripped, bleached, oiled, then dried and varnished. Don’t fibreglass the bottom, no matter how badly you want dry feet. Never mind that slapping fibreglass on an old wooden boat decreases its value; the wood under glass can’t expand or contract. If it gets wet, it will buckle or crack the glass.