I found a bunch of spider cracks on the bottom of the boat. I have no idea how long they had been there. Looks it had been awhile and I didnt check under the boat when I bought it. At this point I had taken a deposit from I guy that bought it from California sight unseen.. I didn't want to sell it to the next guy in this shape so I figured I'd fix the cracks before he picked it up
I ground out the cracks using a Dremmel tool, then filled the cracks with color matched gelcoat material from Spectrum Color. Malibu had used two different colors of white in 2002. "Moon Beam" or "Bright White"
I couldn't find a Malibu color chart so I took a chance and ordered a quart of the bright white.
I didn't snap any pics of the repair process but what I did was use a layer of masking tape around the cracks to keep from sanding into the existing gelcoat. I used a paint brush to fill the crack with as much gelcoat as I could get in there. The gelcoat is pretty runny and you aren't able to get much to stick with it being on the underside of the boat. In hindsight I should have used plastic to help force it into the crack. I keep thinking that one more coat with a paint brush would do it...I ended up filling and sanding it 10 times. For the final finish I sanded with 180, 300 1000, 1500 grit and then used a polisher with Meguiars Mirror Glaze #49 Oxidation Remover to buff to a shine.