Hull bottom paint question- What am I looking at?

pbyrne · February 10, 2022, 02:07:55 PM

Need a bit of help understanding what I'm seeing. The boat is in freshwater, and gets a VC17 antifouling every year. It looks like some kind of paint needs to be replaced, but I don't know if it's the barrier coat or...?

To make matters more interesting there is a note in the manual that says:

"Bottom Painting and Blister Protection:
Calalina models are manufactured with an integrally molded blister protection system in the hull laminate. This water absorption barrier material is between the gel coat surface layer and the laminates of the hull.

The bottom may be prepared for painting using conventional de-waxing solvents, then sanding the gel coat surface or using a chemical etching primer. The keel has been painted using epoxy primer, filler fairing compound and finished with epoxy paint. This material is a suitable substrate for most anti-fouling systems"

So does this mean a barrier coat was/is needed?

This is all new to me, what am I looking at and what needs to be done?

Also, is there a low maintenance bottom that can be put on instead of VC17? We're in the Great White (ice and snow) North, so it's haul out and launch every year, and a power wash at the end of the season whether we want one or not. VC 17 is rather expensive, and I'd rather spend the $100s on the boat itself if possible.

Jim Hardesty · February 10, 2022, 03:12:39 PM

Not sure if I'm answering your questions. But, here is my experience with Shamrock on Lake Erie. In a normal season will do over 1,000 kn some double that. Very happy with VC17.

When pulled at seasons end paint looks good, some algae, maybe a couple of zebra muscles between the rudder and hull. Gets a good pressure washing.

Over the winter get some, very little, a couple of square feet, bottom paint flaking off. I think it's from a too thin of a barrier coat and moisture gets in the gelcoat, then flakes the paint when it dries out.

Spring I go over with a 3m pad, especially the areas of flaking. I repaint the entire bottom. Takes 2 to 3 cans and about as much acetone thinner using a high volume low pressure paint sprayer. Takes me half day, was half that when I was younger. The paint goes on so thin buildup is no problem. Because I mainly use the sprayer for bottom paint only clean up is to run a little acetone thru.
I'm not a fan of Harbor Freight but my friend likes his.
https://www.harborfreight.com/high-volume-low-pressure-spray-gun-kit-44677.html

That's what I do. Sailors that sail less just do a touch up.
FWIW I don't think in fresh water there's any growth that harm the hull. Bottom paint only retards the growth and doesn't protect the hull.

That's what I do and it works for me.
Jim

Kyle Ewing · February 10, 2022, 04:51:42 PM

pbyrne,

I use VC-17 on Lake Michigan and my experience is similar to Jim's, however I roll mine on instead of spraying and use 2-3 cans per coat. I must still be young because I can do a coat, including taping (waterline, prop, transducers) in a couple of hours

. I sometimes skip a season if I'm short on time and it works just as well.

Your paint looks pretty thin so I'd put at least one coat on. If you don't, worst case is you get a build-up of slime or algae which will slow you down. You can clean (or hire someone to clean) the hull in the water. Ask around to see what others do. Some people would rather pay a diver than buy bottom paint. Interlux usually has sales/rebates in the spring.

Here's what freshly painted VC-17 looks like.

pbyrne · February 10, 2022, 06:13:53 PM

So the navy blue, is the barrier coat and the white showing through is the gelcoat? Or is the navy blue what's left of the VC17 and the white showing through is the barrier coat?

Sorry, I'm trying to figure this out.

Based on what you said it sounds like the navy blue IS the barrier coat, and the VC 17 applied in the spring is completely gone?

Meaning I need to paint on a new coating of barrier coat and then apply the VC17?

Quote from: Jim Hardesty on February 10, 2022, 03:12:39 PM
Not sure if I'm answering your questions. But, here is my experience with Shamrock on Lake Erie. In a normal season will do over 1,000 kn some double that. Very happy with VC17.

When pulled at seasons end paint looks good, some algae, maybe a couple of zebra muscles between the rudder and hull. Gets a good pressure washing.

Over the winter get some, very little, a couple of square feet, bottom paint flaking off. I think it's from a too thin of a barrier coat and moisture gets in the gelcoat, then flakes the paint when it dries out.

Spring I go over with a 3m pad, especially the areas of flaking. I repaint the entire bottom. Takes 2 to 3 cans and about as much acetone thinner using a high volume low pressure paint sprayer. Takes me half day, was half that when I was younger. The paint goes on so thin buildup is no problem. Because I mainly use the sprayer for bottom paint only clean up is to run a little acetone thru.
I'm not a fan of Harbor Freight but my friend likes his.
https://www.harborfreight.com/high-volume-low-pressure-spray-gun-kit-44677.html

That's what I do. Sailors that sail less just do a touch up.
FWIW I don't think in fresh water there's any growth that harm the hull. Bottom paint only retards the growth and doesn't protect the hull.

That's what I do and it works for me.
Jim

pbyrne · February 10, 2022, 06:15:22 PM

It's the navy blue paint showing the white I can't figure out. Is the navy blue the barrier coat..? and the white showing through is the gelcoat? Sorry new to all this.

Quote from: Kyle Ewing on February 10, 2022, 04:51:42 PM
pbyrne,

I use VC-17 on Lake Michigan and my experience is similar to Jim's, however I roll mine on instead of spraying and use 2-3 cans per coat. I must still be young because I can do a coat, including taping (waterline, prop, transducers) in a couple of hours . I sometimes skip a season if I'm short on time and it works just as well.

Your paint looks pretty thin so I'd put at least one coat on. If you don't, worst case is you get a build-up of slime or algae which will slow you down. You can clean (or hire someone to clean) the hull in the water. Ask around to see what others do. Some people would rather pay a diver than buy bottom paint. Interlux usually has sales/rebates in the spring.

Here's what freshly painted VC-17 looks like.

Kyle Ewing · February 10, 2022, 07:14:31 PM

I bet the blue is the VC17. Rub the paint off at the boot stripe (use acetone or paint thinner) to see what's under it. I think you'll find a light gray barrier coat that'll be easier to see next to the white gelcoat.

pbyrne · February 11, 2022, 08:15:57 AM

Will do.

Do you happen to know what the right compound is for touching up the keel? Its got some, uh, repairs needed. Some of them are round 12" diameter. on the leading edge of the keel. It's not too obvious but you can see it faintly in the photos, in a few places.

Might as well fix that too.

Quote from: Kyle Ewing on February 10, 2022, 07:14:31 PM
I bet the blue is the VC17. Rub the paint off at the boot stripe (use acetone or paint thinner) to see what's under it. I think you'll find a light gray barrier coat that'll be easier to see next to the white gelcoat.

scgunner · February 11, 2022, 08:26:51 AM

pbyrne,

Whether you've got a barrier coat or not what difference does it make? It looks like there are zero blisters on the hull so whatever you've got is working. The only problem I see is the need to cleanup those dings on the leading edge of the wings. Otherwise prep it, paint it, and plop it.

pbyrne · February 11, 2022, 01:54:53 PM

Yeah I just want to keep it that way!

What would you use to path up the keel?

Quote from: scgunner on February 11, 2022, 08:26:51 AM
pbyrne,

Whether you've got a barrier coat or not what difference does it make? It looks like there are zero blisters on the hull so whatever you've got is working. The only problem I see is the need to cleanup those dings on the leading edge of the wings. Otherwise prep it, paint it, and plop it.

scgunner · February 12, 2022, 08:21:15 AM

pbyrne,

I use West Systems for patching and fairing. It gives excellent results. Your keel will not only look brand new after paint it may also improve performance.

KWKloeber · February 13, 2022, 01:06:59 PM

When she was on Lake Erie I completely took down the bottom and applied 8 coats VC Tar barrier coat then VC-17 anti foul. So very easy to maintain VC every year.

BUT now that she's south and therefore not seasonally on the hard, VC-17 is a PITA. Now I'd LOVE to have a hard or ablative paint -- but cannot (easily) apply that once VC has been used.

Noah · February 13, 2022, 01:30:50 PM

My recommendation Ken: sounds like time for an old fashioned "Scotch and Soda Blast". Hire-out the soda blasting and drink a fine single malt while watching them work.

Steve_in_lex · February 13, 2022, 02:48:52 PM

Love it. When we bought ours we had her soda blasted to take 8 years of paint off, and resurfaced from scratch. She came out beautifully. Forgot about the scotch though! Next time.

KWKloeber · February 13, 2022, 06:13:32 PM

Quote from: Noah on February 13, 2022, 01:30:50 PM
My recommendation Ken: sounds like time for an old fashioned "Scotch and Soda Blast". Hire-out the soda blasting and drink a fine single malt while watching them work.

Jim Hardesty · February 14, 2022, 12:59:39 PM

QuoteBUT now that she's south and therefore not seasonally on the hard, VC-17 is a PITA. Now I'd LOVE to have a hard or ablative paint -- but cannot (easily) apply that once VC has been used.

I've given that, removing VC-17, some thought. I'm thinking acetone or other solvent and lots of wiping. Then some light sanding.
What is the PITA of VC-17 south. I'm thinking, in the back of my alleged mind. that I may do a cruise to Fla for a couple of years. What would be the problem with VC-17?
Jim