Bottom Paint

markrienecker

New Member
Found the j 24 I've been looking for but it has never been bottom painted. I will be mooring and need to know the best anti foul to use for speed and approximately what this should cost from my local boat guy. Is there a template that is used to judge the waterline on a clean hull?
 
the "best" bottom paint really depends on the geographical area that the boat will be moored. We use VC-17 for freshwater inland/great lakes here in Ohio, but that's all that I can attest to.
 
the "best" bottom paint really depends on the geographical area that the boat will be moored. We use VC-17 for freshwater inland/great lakes here in Ohio, but that's all that I can attest to.
Thanks, I will be morning in Port Jefferson harbor in salt water off Long Island sound , any suggestions?
 
One Qt. of VC-17 just barely covers the hull. I needed to open the second can to do the rudder and the cradle patches.
OBTW: this is tricky stuff. The second coat will dissolve the first coat, so you cannot build it up thick in critical areas (leading edges).
I will comment back when I pull her out in the fall.
 

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Applying multiple coats of antifouling paint is very counterproductive. The only coat that matters is the one that touches the water. Antifouling (bottom paint) is made up of the physical binding material, antifouling material, coloring and the volatiles that allow you to apply it. The physical bonding materials are the "paint" itself. It contains the resins that bind all of the ingredients together and stick it to the hull. It does nothing against fouling. The color pigment provides the color that you see and they also do nothing against antifouling. The volatiles are what evaporate away and allow the components to set up and "dry" and it is the antifouling additives that provide you protection against growth and slime.
The antifouling agents protect against slime, organic growth and discourage critters from attaching to your hull which helps retain your boats performance. Antifouling agents are materials such as tin and copper (tin is no longer allowed unless it is a government vessel (rules for thee not for me)). They also add chemicals that discourage or kill biological growth. Over time the antifouling agents become used up and the fouling gets worse and worse. Think of it like a battery. While the battery is fresh the light shines and darkness is defeated. Over time the battery dies and darkness takes over. When the light is too dull you change the batteries (apply a new coat).
Bottom paint does not keep water out, it is only designed to inhibit growth and provide a uniform appearance and color. Over time the resins in the binding agents die and adhesion is lost with the hull. Applying a new coat over top of dead paint does not fix the adhesion issue of the very first coat. The more coats you apply typically the rougher the bottom becomes especially when it begins to flake off from below. A rough bottom or a fouled bottom, same result... slow. To combat against coat after coat build up problems manufactures have designed paint that wears away or ablates. Ablative paint physically wears away over time and helps eliminate the constant build up. The quicker it wears away the thinner it will stay and the less chance of flaking and rough surface finish. As it wears away it also exposes fresh antifouling agents which is a good thing. Applying three coats of a non ablative paint means the first two coats won't do anything because they are buried. Pettis Vivid is for the most part a hard non ablative paint. Added coats adds only money and weight, not better antifouling.
I ask people all the time when they come in for new bottom paint, how is your bottom? The typical answer is, it looks fine! Looks mean nothing. House paint looks fine but it will not protect against growth. To really know, you must see the boat when it is pulled, not after it is power washed. They all look pretty good after they are washed but before power washing most look pretty bad.
VC17 is one of the most expensive paints per quart and it wears away the fastest. For many that is counterintuitive, but that is exactly what you want. You want it to wear away so it doesn't get thicker and thicker and you want it to wear away to constantly expose new antifouling for better protection. On most boats the leading edges will be almost bare in one season. Perfect!
VC17 is also one of the most slippery paint available. It is so slippery (contains TPFE - teflon) that trailering or travel lift (sling) launching can be a problem. VC boats on trailers don't stay put while in motion. They will slide forward while braking and backward while accelerating. Hanging in straps while in a travel lift the straps will slide along the hull and head for the ends. VC is most used in fresh water but it is a very good paint in salt as well.
It is designed to be applied every season because it disappears. If you are in a situation where the boat stays in years between haul outs, VC is not for you. If you are looking for the fastest bottom and the least buildup year after year, VC is the ticket.
Dale
 

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