1998-2000 Yamaha WaveRunner GP800 Factory Service Manual, Page 202Get this manual
;I_H_U_LL C_-r_= HULL REPAIR
Shallow scratches 1Sand the scratches with 400 grit sandpaper (either wet or dry) until the scratches are smoothThen, sand the scratches once again with 600 grit sandpaper (either wet or dry)
Deep scratches 1Remove any sharp or rough edges from the hull surface2Sand the scratches and 1-inch circumference around them with 80 grit sandpaper (either wet or dry)3Clean the entire area with acetone and let it completely dry4Mix gel-coat and gel-coat thickener to form putty, and then add the catalyst to the putty5Apply the putty, spread it with squeegee, and then cover the putty with wax paper6When the putty has set, sand itSmooth the area with 80400 grit sandpaper (either wet or dry) and sanding block7Clean the area with dry cloth and then polish it