Smoothest application of bottom paint short of spraying

[akuakai]

Has anyone found a good process for applying bottom paint that produces a reasonably smooth surface without spraying. I know the limitations of applying a thick paint with a roller is asking a bit much. And it doesn't help that paint thickness is the objective. Foam rollers? Thinning the paint? Anything else?
The last time, which was also the first time, we had a yard apply bottom paint the bottom of our carefully faired (by yours truly) catamaran looked like the surface of the moon. I could see where they back rolled areas where the paint was already drying and really made a mess of it.

[ben373]

I spray but would like to follow.

[SailingHarmonie]

If you are a high end racer, and you need a glass smooth bottom you should know the answers already.

For a cruising boat, a roller surface is just fine. Every paint manufacturer has a recommendation for the type of roller to use to get the proper film thickness. Follow the recommendation of the manufacturer. Unless you know more about paint than they do.

[Uncle Bob]

Originally Posted by ben373

I spray but would like to follow.

Ben, would love to know whereabouts in sydney they let you spray antifoul paint.

[GILow]

Ablative bottom paint is going to be smooth within days of going in the water.

And as noted above, plenty smooth enough for a cruising boat.

I’ve always rolled my anti foul and never had a problem with even coverage. I pressure wash back to the blue guide coat under the black at each slipping so I’d know if there were serious thickness irregularities.

[jcapo]

A boat in the yard near me rolled and tipped. Looks good but ...

[Bill O]

Use a better roller then burnish/polish the bottom paint (hard) before launching for a smooth bottom.

[fstbttms]

Bear in mind that anti fouling paint longevity is 100% dependent upon how much biocide is on the hull and when you sand or burnish the paint, you are removing biocide and therefore shortening the paint's lifespan.

[rslifkin]

Originally Posted by fstbttms

Bear in mind that anti fouling paint longevity is 100% dependent upon how much biocide is on the hull and when you sand or burnish the paint, you are removing biocide and therefore shortening the paint's lifespan.

Yes, the important criteria isn't the amount of paint you start with, it's how much paint you have on the hull at the end of the process.

[akuakai]

Maybe a little more explanation is needed. Our catamaran is somewhere in the middle between outright racing catamarans and cruisers. We're originally small catamaran sailors and enjoy reaching along at 10-12 knots on our 42' catamaran. Its tough to look at a bottom that is needlessly cratered with uneven paint and since I clean the bottom I get to see those craters about once a month. Some have names.

After the paint was applied I noticed (and still notice) areas where the paint is reasonably smooth (not quite spray smooth) but closer to what you'd see when painting a door with a foam roller. So I know it can be done. Just like to reproduce that all the way around. By the way, the roughest areas seem to hold on to the growth far better(or maybe thats the other way around). Anyway, bottom cleaning is a lot faster and easier where its smoother and not so pitted. Another benefit.

Looks like a painting experiment is in my future. I'll try a variety of rollers and do a little research with the paint manufacturers. Always fun to see who's techs are helpful.

[Chotu]

I think the answer is you have to do it yourself because you can’t trust them to do a good job as you found out.

It’s easy enough to get a nice smooth surface with bottom paint using a roller. Short nap. Maybe even foam I don’t know I have not used foam.

But then it all gets pretty darn smooth with use as well

[ben373]

Originally Posted by Uncle Bob

Ben, would love to know whereabouts in sydney they let you spray antifoul paint.

Hi Bob, I have it sprayed at Mac Marine in Pittwater.
For me it is important to not have too much buildup. Spraying provides a good even thin coat.

[ms.lau]

You'll get a better result using a foam roller, small roller is better than large. More thin coats rather than few (one?) thick coat(s). Don't rush.

[Bill_Giles]

Remove any loose paint from before. Level off anywhere where the pint has come off. Apply a single light coat of finish and brush in along the fore and aft direction.

[Goodxcharly]

I use to roll a heavy coat with a 3/4 roller and lay it off with a brush horizontally. Worked fine.
Now I do what the manuf. suggests.