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Land lubber
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Discussion Starter #1
My new to me sailboat looks like this on the bottom.



I have already started the sanding. I planned to repaint the barrier coat. Is there any reason to do the antifouling paint as well? I have no plans to leave it in the water. It will be put in for a day then trailered home with perhaps an occasional overnight camping trip to an island...

Also, am I just being anal thinking I should drop this swing keel and paint it too? If I do, what sort of paint should I use. It is an iron/steel keel.

 

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Master Mariner
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That keel looks to be in terrible shape. I'd suggest stripping it all the way back to shiny metal, priming and repainting. You may need to chip away the patches of scale and if you wanted a fair surface, you will have to fill and sand these areas. If the keel looks this bad, it might be prudent to check the cable or whatever system you have to bring it up and down, as it seems the PO wasn't too big on maintenance.
I can't tell on the hull, but it also looks to need some loving care. I'm not so sure a barrier coat without paint (not necessarily bottom paint) is the best way to go.
 
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Don't call me a "senior"!
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If you are going to dry sail the boat it won't need antifouling paint. I had a 21-foot boat for several years that I dry sailed in SF Bay and it had a run-of-the-mill topside paint on the bottom; no barrier coat, no anti-fouling. I never left it in the water for more than a day or two at a time, but the paint seemed to tolerate those short periods in the water just fine.

The swing keel in your pic looks like it needs a bit of attention, bit I've seen FAR worse. Sand and/or wire brush it, slap on some fairing compound, sand it some more, apply some primer, and some paint. In fact, just to be different, you could paint the bottom and the swing keel with contrasting colors (the more garish, the better ;)).
 

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Bombay Explorer 44
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Rent a needle gun [ use eye protection. ] get rid of the rust. Paint with Ospho. Two coats of zinc rich epoxy primer. Fair then two more coats. Do it on a warm dry day and get the first coat of primer on ASAP.

But using a wire brush, Ospho followed by some Home Depot spray galvanizing fair then a coat of anything will do as well. Just keep the paint handy because you will need to keep touching it up.

Not sure what is best for the hull. Definitely rub it down smooth and definitely apply a coat of primer after that ? Not sure. When I had a trailer sailor I applyed VC 17m and it was still looking good when I sold it 2 1/2 years later. But it is not cheap.
 

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Corsair 24
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galvanising spray works nice too to touch up...for the keel...I used the trailer stuff since we dont have fancy paints down here and we where working with the tides...

since you are a dry sailor your worries are minimized each haul out really...touch up and go really
 

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Land lubber
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Discussion Starter #7
Rent a needle gun [ use eye protection. ] get rid of the rust. Paint with Ospho. Two coats of zinc rich epoxy primer. Fair then two more coats. Do it on a warm dry day and get the first coat of primer on ASAP.

But using a wire brush, Ospho followed by some Home Depot spray galvanizing fair then a coat of anything will do as well. Just keep the paint handy because you will need to keep touching it up.

Not sure what is best for the hull. Definitely rub it down smooth and definitely apply a coat of primer after that ? Not sure. When I had a trailer sailor I applyed VC 17m and it was still looking good when I sold it 2 1/2 years later. But it is not cheap.
I have a pressurized sandblast kettle. I think that may be easier...

I just researched Ospho, sounds like good advice!
 

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You need to check the UV sensitivity of barrier coatings before deciding not to paint. Epoxies normally have to be coated with a UV protecting layer or will deteriorate rather quickly.
John
 

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Bombay Explorer 44
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I have a pressurized sandblast kettle. I think that may be easier...

I just researched Ospho, sounds like good advice!
Sandblasting is better just much messier. Lots of yards won't let you do it but I guess you are home.

You can skip the Ospho if you do a good job sandblasting. Just get the paint on right away.

Re the epoxy comment on UV sensitivity it will chalk in direct sunlight. No probs on the keel but maybe on the hull below the waterline.

You probably don't want to spend big bucks so a household oil based outdoor primer and maybe top coat will do.
 

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Land lubber
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Discussion Starter #10
Sandblasting is better just much messier. Lots of yards won't let you do it but I guess you are home.

You can skip the Ospho if you do a good job sandblasting. Just get the paint on right away.

Re the epoxy comment on UV sensitivity it will chalk in direct sunlight. No probs on the keel but maybe on the hull below the waterline.

You probably don't want to spend big bucks so a household oil based outdoor primer and maybe top coat will do.
Yes, I am not at a marina. I have the boat at my auto repair shop.

Should I put the outdoor oil based primer and top coat on top of the barrier coat, or instead of the barrier coat?
 

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Bring On The Wind
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My boat looked similar to yours a month ago, I took keel off, sand blasted, epoxied, faired and painted it, sanded and painted the bottom, did not go through gelcoat. Heres a couple before and after photos.

Keel Before Sandblast.jpg

Starboard Keel After Paint.jpg

Bottom Prior To Paint.jpg

Keel Mounted.jpg
 

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Should I put the outdoor oil based primer and top coat on top of the barrier coat, or instead of the barrier coat?
Barrier coats are for boats that spend a lot of time in the water. If you are not going to use antifouling paint because you intend to haul the boat after every use, then I would forego the barrier coat, given that the gel coat is in decent condition. Spend that money instead on something you actually use, like a new sail.
John
 

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I purchased a new to me boat as well and the bottom looks very similar to the OP's. Is the best way to prep for new paint to sand the bottom and then paint? Also, what is the difference between barrier coat and bottom paint? Personally, I will be in for 6 months at a time in fresh water.
 

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Cincy...There's a lot of information regarding this multi-step process on the Boat US Website:
There are also the paint manufacturers sites: like Petit and Interlux; take some time and check them out.

This is just one article: Boat Bottom Paint - BoatTECH - BoatUS

To briefly answer your question yes..you should sand the bottom to remove any peeling or chipping paint, but you want to be careful not to go so far that you damage the gel coat if it's still intact.

Barrier coat's goal is to keep moisture out, but it can also trap moisture in. So the hull should be clean and dry. Bottom paint is used to prevent marine growth, however it is not impervious and will allow moisture in. So, it's often desirable to barrier coat and then apply bottom paint. Then you maintain the bottom paint.

This is, of course a very simplified summary. The actual process and procedures will vary dependent upon how neglected your hull and keel are and if there are any blisters that need repair or any fairing that needs to be completed.

If doing the keel it's best to take it down to clean, solid, shiny metal, fill, fair, barrier coat and bottom paint.. if it looks like the OP's keel.

There are also many variations of bottom paint. http://www.pettitpaint.com/fileshare/tech_bulletins/antifoulingpainttypes.pdf

You might want to ask around your marina and see what others have success with.
 

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Bombay Explorer 44
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Yes, I am not at a marina. I have the boat at my auto repair shop.

Should I put the outdoor oil based primer and top coat on top of the barrier coat, or instead of the barrier coat?
Instead.

An epoxy barrier coat will do just fine on it's own.

Something like Sherwin Williamss Fast Clad® Brush Grade Epoxy.
 
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