Bottom paint

[mhfowle]

I have a 26 ft. S2 in fresh water. I'm goint to haul the boat out for maintenance soon. What bottom paint is best for fresh water?? I don't quite understand barrier coats. Do I need one. Also could someone give me a brief overview of the steps to properly repaint the bottom.

Thanks A Lot,
Mike

[sailingdog]

Barrier coats are usually layers of epoxy, that are designed to provide a osmosis proof "barrier" so that you do not get osmotic blistering on the hull of your fiberglass boat. Vinylester resins are less prone to blistering than the polyester resins, and epoxy resins are even more resistant to moisture pentration. Usually, a boat is blasted, with soda-blasting being the newest way to do it, and then faired and coated with the barrirer layer. This is done by adding actual layers of epoxy, not just an epoxy-based paint. Then the surface is primed, often with an epoxy-based primer paint, and then the antifouling is painted on.

If your boat is stored in the water, but hauled for the winter, then I would recommend an ablative anti-fouling paint. Fresh water tends to have less growth than salt water. The reason I recommend an ablative paint, is that most ablatives can be hauled and stored ashore without having to re-paint them. Most hardcoat anti-fouling paints become inactivated when exposed to air for long periods of time.

What you have to do to repaint your boat really depends on what kind of paint is on it, and what kind of paint your putting on it. If you've got an ablative, and want to use the same stuff...just sand lightly and paint away. If you've got an ablative, but want a hard coat, you'll need to soda blast the bottom to get rid of the paint, and then prime and paint. If you've got a hard paint and want to switch to an ablative, you might need to soda blast, you might not... it depends on the two paints.

Not all paints are compatible with each other, so you really should contact the paint manufacturer to get their recommendation for bottom preparation.

[Fstbttms]

Originally Posted by sailingdog

If you've got an ablative, but want a hard coat, you'll need to soda blast the bottom to get rid of the paint, and then prime and paint.

This is a fallacy. Modified epoxies can be applied over ablatives after sanding. Removing the old paint is generally not necessary. But as mentioned before, it is always a good idea to check compatibility before applying one type over another.

[sailingfool]

Originally Posted by mhfowle

I have a 26 ft. S2 in fresh water. I'm goint to haul the boat out for maintenance soon. What bottom paint is best for fresh water?? I don't quite understand barrier coats. Do I need one. Also could someone give me a brief overview of the steps to properly repaint the bottom.

Thanks A Lot,
Mike

If your bottom doesn't have blisters you don't need a barrier coat.

Good answers about choice, preparation and compatibility of bottom paints can be found at http://www.yachtpaint.com/usa/ If you have a special case consideration, their phone support is both free and excellent at 800 468 7589

[mhfowle]

Thanks for the info!

One more thing, my bottom paint has sort of a rough texture, sort of like the texure on a wall in your house. I guess it's from not properly sanding whenever painting. Does this rough texture affect speed?

Also should bottom paint be brushed or rolled on?

Mike

[sailingfool]

Originally Posted by mhfowle

Thanks for the info!

One more thing, my bottom paint has sort of a rough texture, sort of like the texure on a wall in your house. I guess it's from not properly sanding whenever painting. Does this rough texture affect speed?

Also should bottom paint be brushed or rolled on?

Mike

The rough texture probably is indicative of too many layers of old paint, resulting in flaking and bumps. If so, its time to strip it all and start over. preferrably by having someone blast the old bottom paint off (we used sand...).

You need to roll or spray bottom paint, otherwise you get an uneven application that takes too long to complete.

[hellosailor]

"Does this rough texture affect speed?"
Yes, and it *probably* slows you down somewhat. But rough textures (think golf ball) can actually speed you up, which is why they were banned from most boat racing circuits.

If you are pursuing ultimate speed, you'll be looking for something like Baltoplate, which can be polished to an almost glassy finish. And of course, you'll be diving on it at least weekly to make sure it is kept smooth and clean.

[ebs001]

Most people in our area use Interlux VC 17. It is only for use in freshwater and is a real pain to remove. It is a hard multi year use antifoulingand works extremely well.

[Fstbttms]

Originally Posted by hellosailor

But rough textures (think golf ball) can actually speed you up, which is why they were banned from most boat racing circuits.

Puh-leez. The rough texture of a boat bottom caused by brush strokes, orange peeling or old layers of paint ain't making ANY boat go faster.

Originally Posted by hellosailor

If you are pursuing ultimate speed, you'll be looking for something like Baltoplate, which can be polished to an almost glassy finish. And of course, you'll be diving on it at least weekly to make sure it is kept smooth and clean.

Take the advice of an experienced hull cleaner and avoid Baltoplate like the plague.

[resdog]

I've been using VC 17 for years on my fresh water sailed boats. The scum and algae that grows on it after a summer is easily removed with a pressure washer at hallout time. Take your bottom all the way down to gel-coat if it has any other type of paint on it before applying VC 17. You can roll it on or use a spray gun. It's expensive, but hard as hell and smooth and it doesn't mind being on the hard all winter.