I often hear of hard core racers who don't use anti-foul paint because they have the bottom of their boat scrubbed (while in the water). What is up with that? If we didn't paint on the VC17 just how fast will the algae / slime grow on our boat up here on the Great Lakes?
Anti-Foul vs Bottom Scrub
- Thread starter Ducati
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The bottom will begin to slime up in about 2 weeks and hair growth occurs when the water warms up with the right amount of sunlight.
I spent 3 weeks this spring removing several years worth of ancient antifouling, so I must at least try to promote the virtues of a clean hull. 
I've been told that in freshwater, if you have a clean, waxed hull and if you're using the boat at least once a week, and you are willing to scrub the waterline twice a month, you can keep the build-up of wildlife down. I don't have direct evidence of this yet; I mostly keep our boat on my trailer when not sailing.
The racers at our club (Solings, Etchells etc) have immaculately smooth and shiny white hulls that get hand-polished before each race. They also spend most of their time on their cradles, when not racing.
But if you're lucky enough to have a slip or mooring for the whole season, and it's too much hassle to scrub the hull regularly, VC-17 is probably the best option.
I've been told that in freshwater, if you have a clean, waxed hull and if you're using the boat at least once a week, and you are willing to scrub the waterline twice a month, you can keep the build-up of wildlife down. I don't have direct evidence of this yet; I mostly keep our boat on my trailer when not sailing.
The racers at our club (Solings, Etchells etc) have immaculately smooth and shiny white hulls that get hand-polished before each race. They also spend most of their time on their cradles, when not racing.
But if you're lucky enough to have a slip or mooring for the whole season, and it's too much hassle to scrub the hull regularly, VC-17 is probably the best option.
without antifoul the bottom will get increasingly harder to scrub. Algea deposit calcium onto the fiberglass. About the only way to remove this calcium once it builds up is to use hydrochloric acid. After a few months the hull feels like rough sandpaper when dry and real slimey when wet. I know this because I put off doing a bottom job one year and paid the price.
Use an ablative bottom paint and the paint buildup problem others are talking about won't happen. Not using a bottom paint on a boat that is stored IN THE WATER is just foolish.
One of the things we've learned on this forum, Ducati, is that phrases like "somebody told me," or "I often hear," are essentially unattributable claims and hearsay, making the basis questionable to begin with. If you said: "My racing friend, Bob, who's won hundreds of trophies, told me..." it'd be a very different thing.
Hard core racers who don't use anti-fouling paint keep their boats out of the water.
Hard core racers who keep their boats in the water use anti-fouling paint.
Two weeks is a pretty good estimate of when you'd expect growth. Even if you hand scrub, as noted, stuff will grow, slowing your boat down. Years ago, we had our C22 in the water in a lake during summers for three or four years with NO bottom paint. We hand scrubbed regularly. On that lake, there was a unique bottom scrubbing machine that was kinda like a carwash but underwater! Mostly powerboaters used it, but we had a swing keel and it worked for us. It took a lot of green crud off at the end of the season, but the underwater hull was never really white ever again.
Why didn't I paint the bottom? Because we used the boat in freshwater in the Lake during the summer and in the salt SF Bay during the winter. We trailer sailed the boat during the winter, so it wasn't in the salt water for lengthy periods.
Use appropriate anti-fouling paint if your boat remains in the water, even if you use the boat every day. Please note that cruisers, who use their boats every day, use paint. They may not always be moving...
Bottom paint in fresh water
I was on a fresh water lake for more than 20 years, btw.
Where'd you get the idea that bottom paint isn't necessary in fresh water? No barnacles, but there are fresh water mussels and "vegetable" growth that can easily be scrubbed off with a soft brush if the bottom has been painted...if not, it's almost impossible to get off without pressure washing and can sometimes even require a muriatic acid bath. The good news is, bottom paint lasts 5 years in fresh water.
I was on a fresh water lake for more than 20 years, btw.
The hard core racers at our club (Lightnings, Melges, Flying Scotts, Sonars etc.) keep their boats on trailers when not in use. We call them 'dry sailors', the boats that is.
They keep their rigs up all season and either use the ramp or the cranes that our club has for deploying and pulling their boats for each use. This way they can polish and wax their hull bottoms to their hearts content and get that extra 1/10th of a knot.
I tend to agree with SailingDog about ablative bottom paints in that they constantly erode, especially when power washed, and thus do not build up in thickness as quickly as other hard paints. However, it is my understanding that VC 17 is the paint of choice for the Great Lakes as evidenced by some of the above posts from other GL sailors.
They keep their rigs up all season and either use the ramp or the cranes that our club has for deploying and pulling their boats for each use. This way they can polish and wax their hull bottoms to their hearts content and get that extra 1/10th of a knot.
I tend to agree with SailingDog about ablative bottom paints in that they constantly erode, especially when power washed, and thus do not build up in thickness as quickly as other hard paints. However, it is my understanding that VC 17 is the paint of choice for the Great Lakes as evidenced by some of the above posts from other GL sailors.
If you consider the entire costs associated with a bottom paint job, including haul out, block, sanding, solvents, application devices, buckets, masking, cost of paint for a 40' hull youi might compare that with a diver scrubbing the bottom every 10 days if you have a 5 - 6 month sailing season.
I suspect if you scrub regularly you and often you can prevent most build up.
My RIB has a painted alum hull and is in the same water as the mother ship. It goes pretty foul in a month, but it is easy to scrap off the crude and nothing remains but smooth shiny epoxy painted aluminum. I think that doing that every 10 days would make it even easier and faster and I think this can be applied to a larger vessel if the diving cost is reasonable and the season short enough as in New England.
And you save hauling all that weight arounf and fouling the waters too.
I suspect if you scrub regularly you and often you can prevent most build up.
My RIB has a painted alum hull and is in the same water as the mother ship. It goes pretty foul in a month, but it is easy to scrap off the crude and nothing remains but smooth shiny epoxy painted aluminum. I think that doing that every 10 days would make it even easier and faster and I think this can be applied to a larger vessel if the diving cost is reasonable and the season short enough as in New England.
And you save hauling all that weight arounf and fouling the waters too.
Definitely VC17 is the choice for fresh water ... and the smoother you can put it on (and then 'burnish it') the better.
Most times if the VC17 is very smooth once you get up to planing speed, most of the 'crap' will fall off ... but, that requires that you do lightly wet sand the hull a few times during the season.
That said, if your boat isnt 'moving' in the (fresh or salt) water often but stays in its slip most of the time, then absolutely no bottom paint is going to prevent 'growth', even the 'ablatives'.
Most times if the VC17 is very smooth once you get up to planing speed, most of the 'crap' will fall off ... but, that requires that you do lightly wet sand the hull a few times during the season.
That said, if your boat isnt 'moving' in the (fresh or salt) water often but stays in its slip most of the time, then absolutely no bottom paint is going to prevent 'growth', even the 'ablatives'.
Five years of VC17 build up is less than what is left after powerwashing one season of an ablatative off. It goes on so thin and smooth.
It is very popular in the Great Lakes for many reasons, with the most important one being THAT IT WORKS. Ease of prep and speed of application, with virtually no build-up are also great qualities of VC17.
Go ahead and scrub your bottom for one season with no bottom paint and you will realize how foolish that was.
I've got a 34 foot boat, cost say $85 a bottom scrub, plus zincs.
You do the math extrapolated to a 40 footer...
I too use the VC17m on my boat in Lake Erie. Works good for a couple years before needing reapplied. At least once a season I'll brush the bottom while anchored off a beach or sandbar. I do find that I get more buildup near the waters edge, but I usually brush that off when washing the boat. I power wash the bottom when I get it home and there is just a thin film of slime. The VC17m holds up well to the power washing. I've seen other boats being pulled at the end of the season that didn't have bottom paint. The sides are nasty, but the actual bottom is not so bad. Probably due to lack of sunlight and friction from use.
JerryA
JerryA
Fouling occurs in stages. The slime layer is the first stage. Eating sized oysters is the end stage. Abaltive paints prevent anything over a certain size from attaching firmly. Since I am sailing year round the thought of scrubing the hull in 55-60 degree water is not appealing. Even during the summer spending time scrubbing the bottom is not appealing.
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