Well this might not be the "best" solution or advice, but in my case it was a solution that I was kind of happy to be doing. I'm not one for using and mixing toxic chemicals and wearing safety suits and masks to do a small patch job. I was just looking for a very simple way to do it.
http://www.evercoat.com/productDetail.aspx?pID=102
Got this tube as a christmas gift and gave it a try about a month or two ago. It is still holding on there. I do have to "top it off" to make it level and then sand to smooth it out. But right now its doing the job and keeping water out of the fibreglass layer.
If you take a look at the attached picture, it shows the gash that is on my port side of my boat. It is approximately 4 inches long. I really should have snapped an "after" shot to show you how it came out.
To apply it all I did was:
1) dremel sanded the area around the gash so it was somewhat smooth
2) blew on it and used a towel to try and remove dust (no acetone for me!)
3) opened the tube and squished it into the gash, then moved the product around in the gash to stop drips until it set
I was doing the dremelling while the boat was bobbing up and down on water at the dock.. lol. Even with a gash my size I still have tons of product left in the tube for future use. As a first time for me doing this kind of repair, I know I put too much in it for the "first coat". But it did eventually set and hold.
So if you just have a small scratch, this product might be worthwhile to you.
Patching deep scratches
