Re: Do it yourself
You will probably want to remove the rubrail, at least enough to repair this correctly.
Then tape the area, just about an 1/8" outside the damaged area. No need in making the project bigger than it needs to be.
The only glass you'll need to grind out is this loose stuff. It sometimes turns white when air gets underneath. But it doesn't look like much is bad there.
Sand carefully with an aggressive grit until you get the bevel you need from the edge of the repair to the middle of the damage. 45 degrees is a good rule of thumb. The repair has to have a good land to hold.
Pull the old tape and retape.
Clean with acetone before you apply any resin.
You may need to apply a layer of mat with resin, but probably not.
Color match your gelcoat to an area of the boat that you've sanded lightly. That's the color you want to match. Mix enough for the entire job, add catalyst to a small amount in a separate cup according to the gelcoat instructions and mix thoroughly.
Add cabosil and mix till consistency of smooth peanut butter.
Spread into area with plastic spreader. It looks like an outside radius you're working with, so try to go from end to end as you spread. You'll want to get the basic shape with the first coat. Be sure to press it down into the area, then light stroke back over to smooth. Don't waste a lot of time trying to get it perfect, just get it close
Carefully remove tape before the paste dries. Let it cure completely, at least 24 hours. You can remove ridges in your work while it is partially cured with a grater. This will save you much sanding time.
Retape and sand carefully with a 120 grit until smooth and slightly depressed from original gelcoat.
You will probably have to repeat a couple of times, but sand with 180 next time, then 220. Always sand so that area is slightly depressed. If there is wax in your gelcoat, rinse with acetone between applications.
Lastly, spray with color matched gelcoat until you have a very slight buildup.
Let cure, wet sand with 320, 600, then 800 grit.
It will take a few days, but mostly wait time.
Not really difficult, just take it a step at a time.
Good luck!
