I did our 25' express cruiser
a few years ago with Interprotect. It's not hard to work with just follow the instructions. I'm assuming you're not going to take all the gelcoat
off? The yachtpaint.com web site has good instructions on prepping the surface for barrier coating. Be careful once you get your hull
stripped that some of the crazing isn't actually spider cracks. They're potentially problem areas that barrier coat will not fix.
Get good rollers when applying the epoxy
barrier coat. The cheap
foam type from the big box stores won't work. The epoxy
components will eat the foam right off the roller handle in only a few minutes. The best ones I found were the short nap rollers from TimbrMart.
Doing that job outside is almost a must. The fumes from the epoxy paint
is noxious and dangerous. A good respirator and tyvek suite (or sleeves) is essential. The stuff gets everywhere!! We followed up with XXX anti-fouling
and that's nasty stuff too. Don't ever sand it, the dust will kill ya!
It's a good job for the DIY's as long as you take time to read the instructions!