You're playing with potential huge disaster if you try to do the boat.

Suggestion: If you know and artist with oil paints, (once it's glassed and done) see if they can match the surrounding color and texture. Then paint some varnish over it once dry. I paint and if you try it, get some yellow ochre, white and maybe some burnt umber (dark brown) and you'll be able to mix a color and camouflage it almost perfectly. A good airbrush artist could do it too.