bottom job or sand and paint?

[jdrutten]

My boat is on the hard for the winter and I'm trying to think of my spring projects. High on the list is bottom paint. The boat has what appears to be at least 2 but probably 3 layers of various mottled paint. The outer coppery/blue layer (the colors look different in my attached photos, but it's really the same) appears to be VC17 or similar hard paint. Most boats in the marina seem to use VC17. Under that is a light blue layer that appears to be an ablative paint. It rubs off on my fingers. The bottom brown/green layer is harder to distinguish, but seems like it is a hard paint, but in some spots doesn't even seem to be present. There are also some small spots where the paint seems to be gone entirely, but I'm not sure if it's gelcoat or a barrier coat. I have no idea if there's a barrier coat or not.

With my limited experience, I'm struggling to figure out how to approach this project. I'm not really sure what's currently on the boat except that it appears to be a random assortment of bottom paints. Ideally, it seems like I should probably strip it down to the gelcoat, apply a barrier coat, and paint with VC17. But the boat bucks can start to add up with this approach, especially if I decide not to undertake the universally loathed and derided process of scraping/sanding/stripping on my own. Do I really have any other options? The VC17 tech sheet (https://www.international-yachtpain...30.280991636.1637343313-1965470129.1636647253) suggests that it can be applied over "conventional antifoul" with sufficient sanding, but somehow that wouldn't feel right. I don't even know what "conventional antifoul" even means. I'd appreciate any insights!

 

[Justin_NSA]

IMHO, If your bottom isn't super smooth. it defeats the purpose of VC17, which is to go fast. Boats in our marina like to use it too, but I don't agree. When we haul out boats with the stuff, the algae is still green, as in alive.
I use Hydrocoat and it kills marine growth.

 

[dlochner]

Pretty much what @Justin_NSA said. A bottom job is in your future, however, unless you are racing I would leave it alone for another season. Much of the stuff on the bottom will be gone after a season, which means less work for you when sanding. Especially after power washing.

VC 17 is popular with the go fast guys because it leaves a very smooth fast finish. It also does not build up like traditional ablative and other hard paints. I used it for years on Lake Ontario. It is also easy to clean and apply.

 

[DayDreamer41]

If you choose VC17 then I would plan on taking the bottom down to Gel coat, sanding with 320 then 600 then 800, barrier coat, sand to 600-800, barrier coat, sand to 600- 800 then wet sand then apply VC17. If ablative is your selection, uniformly sand with 80 grit and apply something like Seahawk 33 personally on our cruiser we apply the latter, its been 5 season since a full recoat, all I do in the spring is sand 80 grit in spots where the paint has experienced separation and about 16" down all the way around from the water line. Boat looks great when it was hauled a few weeks ago.

 

[Davidasailor26]

The Interlux compatibility chart at Antifouling compatibility | International is much more critical of VC17 compatibility than the VC17 data sheet itself seems to be. I would not try to put more VC17 over what you’ve got there. The under layers will eventually peel more and you’ll just have a harder time removing it all.

 

[Siamese]

Like you, my boat is kept in fresh water (slipped on Muskegon Lake, and sailed on Lake Michigan). I've been using V17 for years. It's easy to apply, and it doesn't build up. I put on a light coat each year. For prep, I just rub the hull with a scotch brite pad. Bottom is smoooooth.

If your boat was mine, I'd have it down to bare gelcoat. Barrier coat followed by a coat of V17.

 

[sesmith]

VC17 is great stuff. I use it on our boat on the Great Lakes. I've never heard of painting it over ablative, though, and can't imagine it holding up with that as a base. So if you want to do VC17, I'd strip it all off. If it were my boat, though, I'd sand off the VC17 and scrape and sand any chipped parts. Then I'd go with an ablative over the existing ablative. It would save the trouble of stripping it all and barrier coating it.

 

[shemandr]

If that were my bottom I would sand it as smooth as possible with 80 grit and put Bottom Coat on it.

 

[jdrutten]

I agree that it doesn't really make much sense to be using vc17 on my current topographic hull. Which of course is why it's so strange that the PO would choose to put vc17 over the top of a bumpy ablative. Sheesh.

I hadn't really considered the option of sanding the vc17 and leaving the ablative layer, or even just simply leaving it as is for another season as suggested by @dlochner. It's good to have options at least.

 

[dlochner]

A few years ago I removed many years of VC-17 from my hull. It is not a job that I want to do again.

VC 17 is essentially powered copper in a thin binder. In high wear areas the copper slowly wears off, in low wear areas the copper builds up. Unlike ablative paint it does not crater and peel, it just builds up. Sanding is the only way to remove it. Where the VC-17 is thin, it sands off pretty easily with 40 grit paper, where it has built up, not so much.

When sanding the sand paper burnishes the copper powder essentially turning it into a solid copper sheet. Ultimately we used 36 grit on a RO sander to slowly abrade away the copper. By the time we were done (many many hours) we had about 5 gallons of sanding dust.

Be prepared for a lot of work getting the VC 17 off. Chemicals and paint strippers did not work, the only solution was aggressive sanding. I had started with 80 grit, but that just polished the copper.

 

[DeniseO30]

If you were to leave it to the people who get the big bucks to do it to it... they'd just slap slop it another coat and tell you they did all the above, which is usually done just before they splash it and you're not around to see professional job you just paid for

 

[Justin_NSA]

That would be worth being there and watching the whole operation.

 

[sesmith]

Be prepared for a lot of work getting the VC 17 off. Chemicals and paint strippers did not work, the only solution was aggressive sanding. I had started with 80 grit, but that just polished the copper.

Wow. Didn't think it would be that bad. Doesn't bode well for if we ever take our boat to salt water. I heard that it could be wiped off with either denatured alcohol or acetone. I wipe mine down with alcohol before painting it each year, and I do know the alcohol cuts it, but I could imagine a lot of wiping and a truckload of rags to actually wipe it all off a 35' boat.

To the OP...if you do opt for taking the VC17 off, you have to get it all of as an ablative won't stay stuck to it.

 

[jdrutten]

... I heard that it could be wiped off with either denatured alcohol or acetone. I wipe mine down with alcohol before painting it each year, and I do know the alcohol cuts it, but I could imagine a lot of wiping and a truckload of rags to actually wipe it all off a 35' boat.

Yeah, I've seen that come up in some of my searches. I actually tested it out a couple weeks back and used acetone to clean up the bottom of my damaged rudder (that's another thread). It did seem like I had to use several paper towels and a fair amount of acetone on just a small portion on the bottom of my rudder. I really can't imagine doing that on the rest of the rudder let alone the whole hull. But who knows, maybe my technique was off?

To the OP...if you do opt for taking the VC17 off, you have to get it all of as an ablative won't stay stuck to it.

Yes! Therein lies the rub (no pun intended)!

 

[Tally Ho]

I use VC17 on my boat (Lake Michigan). Goes on really thin, so you need a pretty smooth surface to apply it to.

My bottom was a little rough (maybe not quite as bad as OP)…I finally sanded it down a bit in the worst areas and repainted.

I do a full repaint every other year, and touch up on the off year. As was stated, the leading edges of keel, rudder and other high wear areas wear off over the season. Other areas, not so much.

Greg

 

[dlochner]

Wow. Didn't think it would be that bad. Doesn't bode well for if we ever take our boat to salt water. I heard that it could be wiped off with either denatured alcohol or acetone.

We removed the VC 17 because we planned to go to salt water other wise I would have left it on. If you are planning to go to saltwater, my advice is to stop painting the bottom and get it aggressively pressure washed for a couple of years to remove as much of the paint as possible.

Solvents work well for very small areas or to clean up spills, however doing the bottom of a 36' boat was a non starter. I did try it and found the solvents mostly smeared the paint around and mopped up a little.

 

[sesmith]

I wish VC offshore worked better than most reviews I've read indicate. It would be an easy switch for saltwater then.