I haven't tried this yet, but have seen good results. It's much better than kevlar paint or whatever applied superficially because it bonds by reacting to the existing surface.
Recipe (courtesy of cartespleinair.org ) :
Ingredients:
-ABS plumbing pipes (i.e. 3 in. diam)
-acetone (4L)
-paint can or large glass jar with cover
Recipe:
-cut the pipes in small pieces (i.e w hacksaw), and put in can
-fill can 3/4 with acetone and cover
-wait 2-4 days, stirring a couple of times per day
-200mL acetone+ 4in long (of 3in. pipe)= putty texture
-300mL acetone+ 4in long (of 3in. pipe)= texture a little thicker than paint.
MEK is another possible solvent (methyl-ethyl-ketone), and vinyl can also be dissolved this way.
remember that acetone requires good ventilation and is extremely flammable.
spread on with spatula or fingers (I don't know what kind of gloves resist this mix- perhaps the chemical ones at Home Depot).
hope this is useful. I'd try a small test first and see how it works on your boat.
OC.
you've got a couple of pics in this file:
http://192.77.51.2/~cleduc/Canot/Divers ... eCanot.pdf