Originally Posted by Nos4r2
You've got to rub the gelcoat down to get it to stick so you'll never get rid of all of it.
Everyone told me that too, but that bothered me as I didn't want my shiny white hull ruined. However, antifouling a must here or there's barnacles and weed everywhere within six weeks.
I bit the bullet for this season, ordered a can of white International Interspeed Ultra. Washed the hull to get rid of last season's wax and just rolled the paint on - no sanding the gel coat, no undercoat. That was early May when the boat was launched. She's out now in expectation of the September gales (where are they?). Ninety five percent of the antifoul is still on the boat and it's worked well. There's barnacles and things on the elephants trunk and the rear end of the tubes, which sit in the water, but the hull is clean and smooth. No regrets on that score. However...
I ordered white. The paint came labelled 'Dover white', looked OK, but when applied was grey :-(. The submerged bit turned 'almost white' after a while, but the bit at the bow in the 'splash zone' turned greenish. I have seen pure white antifoul on yachts and that's what I thought I'd got. Still, it should be fairly easy to get off and I'll find some 'whiter than white' next time.
So, if you moor in a place with heavy fouling then antifoul. You'll get much more ribbing in, I think - but check the colour properly. :-)