This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
When the sides of a boat become scored or bruised scrape the parts clean and fill the depressions with wood cement. The wood cement or stick cement, as it is called, can be procured from a paint store. Heat the cement with a blowtorch and apply it to the bruised parts. Use a heated putty knife to smooth the cement and make the surface level. After sandpapering the fills and applying a coat of paint the boat sides will look as good as new. The cement will not chip or fall out. - Contributed by Henry Beck, Bronx, New York.