Yngmar
Well-known member
Update! The below waterline hull (all 40 ft of it) and keel are scraped completely, only the rudder left to do. Overall I'd say it's a tough but very doable job. You get a great upper body workout and learn a lot about antifouling in the process. The Bahco 665 scraper would be my recommendation, although the Pro Scraper is not far behind and features a hose/vacuum attachment if you're so inclined. I've done it wet (see below) and wore a coverall with hood, cartridge mask and closed(!) goggles. The stuff nonetheless gets absolutely everywhere. Mild allergic reaction on my lower arms, as the coverall let some through.
The stuff comes off three times better when thoroughly soaked, so best done in rain! In fact, I've made the most progress while the boat was still in the slings and the yard staff had gone to lunch. Don't have that cup of tea first, get scraping immediately - it's so much easier before it dries out. After it was in the cradle, I've wetted it thoroughly with a hose whenever it started drying out again, but it's not the same as when the boat is fresh out of the water. In total I've scraped one full day and two half days, but not continuously - took a break because the arms were aching and had another enforced break because the sandblasting guys were hogging the only hose (oh irony).
Thing's I've noticed: In total I've counted 5 layers of blue AF and a grey primer underneath. The strip near the waterline that was only sometimes immersed was much tougher to scrape off than the rest of the hull. The keel (lead) needed less scraping, as the AF there had flaked off in the pressure wash. There were some patches on the hull where the supports must've been that had no primer underneath. In those areas, the AF came off very easily, and the blue colour had seeped into the outermost layer of gelcoat, tinting it blue (seen in photo). Gelcoat was not harmed in the process (grinding the edges off the scraper helps) and the gelcoat on my hull is over 1mm thick where I've seen it.
Next is sanding off the remaining bits to get a clean white, keyed gelcoat for later coppercoating. I've used the random orbital sander in a small test area and it went very fast, so this should be the easier part. I've watched the sandblasting guys clean a large steel hull in the morning and spray on primer in the afternoon, but they came with two vans, two trailers and 5 men that I wouldn't want to pay for, so I'm happy I've done it this way.
The stuff comes off three times better when thoroughly soaked, so best done in rain! In fact, I've made the most progress while the boat was still in the slings and the yard staff had gone to lunch. Don't have that cup of tea first, get scraping immediately - it's so much easier before it dries out. After it was in the cradle, I've wetted it thoroughly with a hose whenever it started drying out again, but it's not the same as when the boat is fresh out of the water. In total I've scraped one full day and two half days, but not continuously - took a break because the arms were aching and had another enforced break because the sandblasting guys were hogging the only hose (oh irony).
Thing's I've noticed: In total I've counted 5 layers of blue AF and a grey primer underneath. The strip near the waterline that was only sometimes immersed was much tougher to scrape off than the rest of the hull. The keel (lead) needed less scraping, as the AF there had flaked off in the pressure wash. There were some patches on the hull where the supports must've been that had no primer underneath. In those areas, the AF came off very easily, and the blue colour had seeped into the outermost layer of gelcoat, tinting it blue (seen in photo). Gelcoat was not harmed in the process (grinding the edges off the scraper helps) and the gelcoat on my hull is over 1mm thick where I've seen it.
Next is sanding off the remaining bits to get a clean white, keyed gelcoat for later coppercoating. I've used the random orbital sander in a small test area and it went very fast, so this should be the easier part. I've watched the sandblasting guys clean a large steel hull in the morning and spray on primer in the afternoon, but they came with two vans, two trailers and 5 men that I wouldn't want to pay for, so I'm happy I've done it this way.
