2003 Old Town Stillwater - How deep do I sand?

I bought Stillwater this summer with quite a few scratches which they are known for. This was not much of concern but I want to switch from factory green to more of a tan marsh color.

I started sanding today to prepare for painting (Rust-Oleum 207003 Marine Coatings Topside Paint). And the green outer paint gave away to the very thin layer of gray, that gave away to a white layer. I would appreciate advice regarding am I sanding too deep or just right. I plan to stop at the white which I am assuming is raw fiberglass. It was not difficult to sand down to the white with 80 grit disk sander.

This picture shows all three layers; green top, gray middle and white from deeper scratch.

This is my first time painting a canoe. Feel free to point to existing articles that explain the process I should follow.

Thank you in advance!

I forgot to mention, there is one round spider crack that doesn’t leak. I was planning to simply sand and paint but maybe I need to do more.

Thanks again!

I painted my canoe with the Rustoleum Topside paint. I would strongly suggest you look at other paints. It is very delicate, scratches, chips, and peels easily. My canoe didn’t have a previous coat of paint, just the gel coat. I painted it due to some repairs I had to make, and thought painting it would make it look better. I made the repairs, sanded the entire canoe, applied a coat of Rustoleum wood and fiberglass primer, sanded again, then coat two of primer. Sanded again, the top coats. It took three coats before I couldn’t see the primer. But it did look good. Until I used it, anything that touched it scratched it. It wasn’t too long before it wasn’t looking too good.
That’s my experience,YMMV.
As for the spider crack, what I did for those was to sand back to the fiberglass, then skim it over with Bondo, sand smooth, prime and paint.

Good Luck.

Thank you, I appreciate the advice!

The green appears to be paint. The grey looks like gelcoat and the white is probably the fiberglass.
I would be careful with the 80 grit. Maybe sand in 2 stages. Go to 120 or 150 for the finish sanding.
The spider crack is structural. It is no big deal to add a layer of epoxy and fiberglass cloth over that whole area. Add some additional coats of epoxy to fill the weave if you need to.

I repaired an OT Canadienne from 1987 that is a kevlar boat. I used the Rustoleum marine paint with good results. Don’t over think your paint. Don’t under think your structural repairs.

Thx for the advice, really like the last two sentences about paint and structure.

If the gray is gel coat, do I need add a gel coat before painting or will the paint provide the sealing of the fiberglass?

Some people seem to like working with gel coat. I have never bothered. You can add some clear epoxy to the scrapes when you are adding the fiberglass patch. Sand them smooth and paint. For deeper gouges you can add wood dust or microballoons or other filler to thicken the epoxy and make it stay put in the gouges.

People always want to make a big deal out of painting a canoe. Don’t. It is easy to touch up. Marine enamel, epoxy paint, oil based porch paint and even latex house paint work surprisingly well. Prep the surface, clean it, apply paint in a clean environment and let it cure for a couple of days. Don’t drag your boat around on the gravel or rocks.

Keep it simple…I like it!

If the gray layer is very thin, it’s probably just primer. When you sand the boat, try not to sand into the glass fibers, as it weakens the layup and it may print through whatever top coat you use. Use the appropriate primer for whatever paint you choose. Wet sand it until you achieve the desired level of smoothness, repeat the prime-sand process if necessary, then apply your top coat.