After a full year of sailing with some time sitting in various marinas, it was time to take her out of the water and see how everything looked below the waterline. In the Caribbean, we had spent some time diving around the boat and even did some scraping with a soft plastic tool to try and get her cleaned up a bit for the passage back across the Atlantic.
Performance
As it turned out, even a little amount of 'crud' on the bottom significantly affects the performance level of the boat. We lost about 1.5 knots of speed because of it. On first glance that might not seem so much but to a boat that is going 8 knots and is now doing 6.5 knots it adds a huge amount of more time onto each passage especially one of two weeks or more.
By simply scraping her clean once in a while, we could maintain her previous performance easily. In warm waters, this was much nicer to do than when we were in cold waters!
On the Hard
Once we reached Spain we had her hauled out and put up on the hard for three days. It was an amazing adventure to see what the bottom looked like after a year in the sea. After the pressure washing we let her dry out for a while then went to work looking at the anodes. They didn't seem too bad and I attribute that to several things. First we spent a much smaller portion of the year in a marina hooked up to shore power. Second, we had an Isolation Transformer between the shore connection and the ships electrical system.
If you don't know, there are problems sitting in a marina with other boats around you who have bad grounding systems as well as the shore power being badly grounded. The net result is that systems on your boat will deteriorate much more quickly. Having adequate protection in the form of an isolation transformer is expensive but not as expensive as replacing engine and generator parts. In our case, I was very glad I had installed this system.
Shipyard
We had contracted with the local shipyard to haul her out of the water and put her up on a hard support for a few days while they renewed the antifoul.
As it turned out, their base fee didn't include anything more than pressure washing the hull, letting it dry out and painting the hull with two coats of antifoul before tossing her back in the water.
This was less than optimal as all the anodes needed to be replaced, the thru-hull openings needed to be cleaned, sanded and re-primed as did the propeller support structure. The bow thruster blades needed to be disassembled, cleaned, primed and re-painted as well. The hull had numerous places where the pressure washing didn't really clean things properly. Some 'crustaceans' were still attached and needed to be sanded off. Actually, we spent the better part of a day just sanding the rough spots off. The propeller needed to be cleaned with acid and polished as well.
This was also a good time to polish the above-water sections of the hull with a UV-resistance wax. It's much easier to do this on the hard as opposed to in the water as you can reach everything easily. Lot's of work can be done while the boat is out of the water much easier than when it is in the water.
The yard has no provision for doing all this work so we decided it was important to spend the time to 'do it right' (I hate doing a 'half-assed' job on anything). We took several days to prep the boat before we let the yard apply the anti-foul.
Once we had the boat properly 'prepped' we allowed the yard to apply the anti-foul in two separate applications. We monitored how they applied the antifoul and made sure every part of the hull was covered adequately. Once the paint was dry, we put the boat back in the water and took her out for some sea trials. She was really fast and we could tell the difference in having a 'clean bum'!
Summary
If you care about your boat and peformance. Don't just let a yard take her out and anti-foul it themselves. Either insist on the items we described above being done properly or do it yourself. At the very least, be there through the entire procedure and make sure they are doing a proper job for you. Remember, your hull will be in a 'hostile' environment for a year before you get to see it again. Take the time to do it right and you will be rewarded by better performance and knowledge that you have taken care of the 'invisible' parts (underwater) of your yacht.
Enjoy your sailing with a clean hull!