Water line sanding ?
 

Kind of a silly question - but maybe one of you has a better mousetrap ? How do you sand your bottom paint at the very top of the water-line where the paint and gelcoat meet ?

I've always used a high-end, ablative paint, but it's gotten layered and thick - and seems to chip along that pain:gelcoat line, making it look like cr*p. Also, that same 2-3" of paint that is not under the water all the time seems to craze a bit and flake off. I find that any of my anti-fouling not immersed in the brine gets rock hard and sometimes brittle. BTW - I use Petit SR 60 - very high cuprous level.

Oddly enough, 10 years ago, when I first got the boat, I sanded as much of the red bottom point off, fairing as I best I could. I rinsed it and topped it with Black Petit. In some areas, the Petit will just NOT stick right and will flake off - any idea why ? I can tell that under that original red, the boat was epoxied, probably with InterProtect 2000 ( looks gray ).

I wetsand that area with 220 every year to keep the buildup to a minimum.