"Oh, the canvas can do miracles"
Does he mean, like, the canvas that artists paint on?
No, you dummy. He means, like, the canvas that sails are made from. Maybe not so much anymore, but they used to be.
Oh, OK. Then that would be Sailing, by Christopher Cross. Pretty song.
This was a #4 hit in 1985:
Doctor says you're cured, but you still feel the pain