farmer boy 8:22am, 5 February 2012
Hi all, I have been wondering if I need to go the whole hog (like I did on Windsong) and remove all the old antifoul with caustic soda and hours of scraping? The previous time I got it back to gelcoat and put on a few coats of primocon before applying the antifoul. What did I achieve by doing that? Can I just give the existing antifouls a good sanding to provide a key and then apply new antifoul on top?
Does everyone remove the remnants of last years antifoul before applying the new?
Maybe its the weather but I am feeling a bit lazy...
craig48uk 7 years ago
I took all Chiron's back to gelcoat when I bought her, there was a large build up there and as I was going to race her I wanted the best possible finish. After sweeping up the flakes, not including the antifouling from the keel, I bagged about 10kg.
What does this have to do with cruising? Not a lot, for someone happily pottering about the coast, but an extra 1/4-1/2 knot over a 24hr period is worth 6-12nm, multiply that by an Atlantic crossing of 3-4 weeks and........If you're trying to make port on passage before bad weather moves in, you'll appreciate the extra speed too.
If your current finish is smooth and all well adhered, then a primer coat of Primicon, or Seahawk will be all that's required. Dissimilar paints won't adhere to eachother.
If you do take her bac to the gelcoat, then it would be advisable to put an epoxy barrier coat on there, such as Interprotect. The warm salty waters of the tropics, cause a lot more osmosis problems than you see here in the fridgid north!
farmer boy 7 years ago
Thanks Craig, I have just had a quick scrape (oh joy!) and the antifoul comes off quite easily leaving the white gelcoat visible below. Might not be as bad a job as I thought.... so... scrape off old antifoul, barrier coat (Interprotect) and then fresh antifoul. Would you recomend a hard antifoul paint, ablative, or coppercoat stuff...
craig48uk 7 years ago
If it's coming off easy, it might not stay on on it's own accord! Take it off, degrease the hull, put the necessary coats of Interprotect on, then your chosen antifouling.
With the amount of travelling you intend to do, I'd suggest a hard antifoul. Boats delivered new from France to the charter base in Tortola, had lost the equivalent of 1/2 their ablative antifouling.
Another thing to consider is that many antifouling formulated for our waters here, are not as effective in the high fouling areas of the Tropics.
Our charter fleet use to use the illegal TBT Micron 44 antifouling, but I changed this to the new non-tin based International Micron 66. Did a good job out there, but was ablative. Having said that the boats were doing up to 35 charters per year and were always moving.
If you don't mind jumping in with a cloth and scraper (and lets face it you won't in warm waters) then a hard antifoul, occassionally rubbed/polished should do you well for a year, maybe longer. Just get the most potent one available before you head off and in a dark blue, or black.
farmer boy 7 years ago
Thanks Craig.... I spoke too soon ...... been scraping all day - I hate boats.... hard antifoul it is... ta
rothwell_neil 7 years ago
Want to borrow a 40 grit belt sander?
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