CTCCC (Captain Tolley's Creeping Crack Cure) is an acrylic, not epoxy, per their website. It goes on milky white, and then dries dark, thus accentuating your gelcoat cracks. Don't ask me how I know... It is also VERY runny, and won't stay confined to the spider crack well, so you'll be tempted to let it go all over the uncracked surface, thinking that the milky will dry clear. It won't, it will darken. Sigh.
On the other hand, I think I had a little leak under my teak toe rail. I ran the CTCCC under the toe rail, and so far I see no evidence of the leak continuing. I'm thinking this off-season will be the year to replace the toe rails anyway, so I can be sure they are properly bedded with Life Caulk or whatever...