Advice on painting a metal centerboard

[Bob_N20]

Hello All,

What is the collective advice about painting a centernoard that swings down below my Nimble 20 stubby keel?

The centerboard is metal (lead according to some on the Internet). When swung upward about about 1/2 of the centerboard's width is still under water.

I've already primed the hull (Interprotect 2000e) and added 2 coats of Micron CSC.

I'm now ready to hoist it so I can drop the swinging centerboard and paint it.

Should I sand, prime and paint the centerboard?  Or just prime?  What have other Nimble sailors done?

Thanks. Bob

[Spot]

You could check the centerboard and stub keel with a magnet to see if there's steel or cast iron in there. My boat has a stub and centerboard of cast iron.

[Riley Smith]

And if it IS cast iron, you should paint it. But first CLEAN it. Maybe someone saved the instructions. Stand by...should be someone commenting further. Which brings to questions, if it WERE lead, what would be the recommendations? To me, lead would tend to be a problem because of the possibility of deformation. Just my thinking at the moment. Seems to me there was some elixir that was used to coat the cast iron with. Without the coating, sooner or later rust will swell the thickness of the centerboard and you'll have problems. Maybe BIG problems it it retracts into the keel. So now is the time to do what needs doing.

[Frank B.]

I had a Columbia 8.7 that had a bolt on lead keel that was not encapsulated in any glass covering.  So,, what seems to be recommended first.  Most folks say clean it meticulously, then put a coat of epoxy on it, then fair it, (while still green) with epoxy thickened with microballoons, then paint it with whatever bottom paint you are using on the hull.

Now what I actually did.  Where I did my bottom there was a guy who traveled around to the marinas and bead blasted hulls and, in particular, lead keels very inexpensively.  When we did our hull we had the lead keel only bead blasted then put the bottom paint right on it without any additional primer.  I didn't notice any ill effects from this process, however, sample of one, I'm not recommending it.

[Norm L.]

I can't remember the details as it was quite a while ago. I still have a lot of Nimble factory details, but they are at the office. I've wanted them home but haven't done that yet.

In my mind they are lead. It is difficult to have something that skinny a fiber thing. The lead I also know of is the stub keel.

The painting as I remember it was a primer and finished with the hull paint. As the boat was kept in the water, the coatings held up well. The fellow that did the work had a part time job at the boatyard as he earned his NA degree at the respected University of New Orleans Naval Architecture school.

You can see I used a rope for the centerboard as it worked neatly with the cockpit bitt. I changed that every year.


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[Riley Smith]

Lead doesn't corrode as cast iron does was the caution. Cast iron will increase in size and create jamming issues as the rust disintegrates. Make sure! Anyway, good job on THAT centerboard!

[Bob_N20]

Thanks everyone. It was lead. Roughed it up with 80 grit and painted with two coats of Interprotect 2000e and the first coat of Micron CSC.

QUESTION. There are what look like 3 metal battens running the width of the centerboard. Two are missing. I only have tomorrow for my boat on the sling, so I don't want to add the extra two battens unless I have to. Anyone (Nimble owners especially) know what the battens are for? I can only guess they prevent the banging of the centerboard when the centerboard is raised (like at the dock).

[Norm L.]

I don't have wonderful memories back 30 years But, the man that bought it still has it and we occasionally talk a bit. And he occasionally asks me if I want to buy it back. Then changes his mind and keeps it.

I don't understand 3 metal battens running the width of the centerboard. Width and centerboard is confusing.

[Riley Smith]

Sounds like your information might be correct if I have it right in my mind. Spacers to keep the cb from clunking.

[Bob_N20]

Thanks Riley. That's what I think too.

Norm, do you or anyone else have the pin-and-ink drawing of the swinging centerboard? I have a copy from the old TS website, but it is blurry.

[Norm L.]

I can't be of any realm help. I thought I had some more interior photos but not many. Looking at this photo I remember taking the cover off the centerboard slot and examining the interior and the movement of the centerboard.  I also liked the metal tube from the centerboard to the cockpit keeping the CB hoist rope free of problems.

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