Dirty Bottom Problems
Odin's keel was in good shape when we purchased it. Even though it had been in the ocean, it had definitely been power washed. There were several places the boat had run aground, but not enough to do any damage. Forward had a bit of ablative paint left on the hull that would need to come off . The aft end of the hull had another type of hard paint that was in rough shape.
I would call the color of Odin and orange tan mix. It's a fairly ugly color, but does make the boat look straight out of the 70s. I knew I needed to bring the bottom down to that color, which I assumed was the gel coat. This gel coat is typically a hard surface, so it's fairly easy to sand off paint without going through the gel coat.
The keel, though in good shape had some rust around the edges. I wasn't to concerned with the rust, as it was all surface rust. Rather than spending weeks dropping the keel, sandblasting, epoxying, and then painting it, I decided to go with a wire wheel and knock off the dust. I then would throw on some epoxy to seal it, and paint over everything I could see. This wasn't the entire keel, but it was close. On a swing keel Catalina 22, there is a portion of the keel that a paint brush is just not going to reach.
This being my first boat, one of the things I worried about is blisters. These occur on fiberglass boats when water, through osmosis, gets underneath the paint and can start causing issues with the hull. They can be fixed, with something like WEST SYSTEM 105-K Fiberglass Boat Repair Kit, but I figured these could wait a year. It didn't look like they had been dealt with for years anyways, so what is one more year.
After donning my respirator mask, I used a rotary palm sander connected to a shop-vac and started sanding at the bow of the boat. I started out using cheap 80 grit sandpaper that I purchased online a few years back. Using cross beams on the trailer I was able to work in sections moving my way back. Within the first two section, I had burned through a stack of 25 sheets. The issue was that the ablative paint at the bow was clogging the sandpaper too quickly, I figured that 80 grit sandpaper was all the same, and I learned I was wrong.
I headed to the store and picked up a pack of quality sandpaper discs and a small wire wheel for the end of the drill. The next day I only went through 5 discs to complete the last 80% of the boat. Holding my arms above my head to sand everything down was painful, not something I am used to. I found that getting the right position that I could prop my was up was best. It only took about 5 hours over two days to complete. I came across several different spots that didn't look great. I covered them in epoxy to seal them in for the season and figured I would so more extensive repairs next year.
The wire wheel was pretty quick at stripping the rust spots from the keel, but in the end I found most of the larger spots were actually already cleaned up and epoxied. I placed another light coat and let it dry overnight.
The next evening I rose my boat on the boat stands about three inches from the bunk boards and did the last sanding. I used some denatured alcohol on several rags to wipe down everything really good. This was an important step really, as the old ablative paint put off a lot of dust that was on everything. Always remember to wear a respirator.
I chose a gallon of red Interlux BottomKote NT because I was able to get a good deal on clearance on defender marine. I liked the idea that it was supposed to be an ablative paint, but it was supposed to be a slower polish so it wouldn't rub off on everything. This wasn't the case but I'll go into that later.
The sailing plan for the year was to sail on the Great Salt Lake from a slip. No barnacles live in the extremely salty lake, so there wasn't a ton of terrible growth to be worried about. Algae can be an issue, but that's about it, and it's not a terrible problem.
The paint was easy to mix by hand, but it is extremely thick so it took a lot of stirring. I used a 3 inch short nap roller and covered the area under the bunk boards in about 5 minutes. Where ever this stuff is rolled, it is almost always complete coverage on the first pass. It's probably the best paint I have ever worked with because of this coverage.
Overcoat time for the paint is two hours, so we waited and then dropped the boat back onto the bunk boards. The paint goes a long way as you roll. I also had a soft paintbrush that I would go back over after I emptied my roller to knock down the ridges and bumps of the paint. This gives the paint more of a gloss smooth look. My wife filled my small tray two time for me for the first coat of the bottom and the keel. The next day we applied a second coat, but did not bother with a second coat under where the bunk boards rest.
The entire process was fairly easy, took a few evenings, but was easy enough. We ended up using a little over a quart of paint for the two coats. We should have enough for another coat next time we haul the boat.
We have had the boat in the water now for three months. There is slime growth after a few weeks of not sailing, but by the time we sail out of the channel, the slime is gone. I have had to use a sponge on the rudder where it doesn't get hit with as much water near the top of the paint line, but it comes off easy. The only bad thing is that it is more ablative than I was expecting. The anchor line has drifted under the boat a few times, and the red rubs off on it. We swim off our boat a lot, and if you hit the bottom, you will still have red on you, something I really wanted to avoid. I have really been happy for the most part with the paint for the first half of this season.
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