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Centerboard Trunk on Aluminum Boats Maintenance Questions

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I have a few questions about the maintenance & coatings on aluminum boats which I could use some help with. Specifically, on aluminum boats with centerboards, I'm wondering how one deals with keeping up both the bottom paint, & especially the barrier coat inside of the CB trunks. Plus, whether or not its common to have dedicated anodes for the trunk walls?

 

The reason I ask is that I figure that the trunks get a lot more wear than does the hull, given that the centerboard is continually rubbing on one side of the trunk, or the other, or both. Especially when under sail. As then the board is being firmly pinned against one side of the trunk by hydrodynamic forces, but it's still moving slightly, under a lot of pressure, via the lift its generating. So then the wear on any & all coatings would be greatly accelerated by this. Right?

And I reckon it wouldnt be easy to monitor the condition of the coatings inside of the trunk either, unlike those on the hull. Which for me, is a cause for concern. Particularly with aluminum's fragility along those lines.

 

So, I'm wondering what kinds of preventative measures that one can take to ensure decent coating life inside of the trunk. As well as how to monitor the trunk coatings' health, if such is even possible. And then, when its time to renew the bottom paint, whats the process for doing the trunks? As on the hull, you'd inspect things, both before & after prepping the old bottom paint for adding fresh antifouling. And touch up any barrier coat where things were at all in question. But as to doing this inside of the trunk... I'm at a loss on the procedures & techniques. Ergo, I need to borrow some wisdom & experience.

 

Thus, it seems that protecting the inside of a board trunk is another matter entirely. So I'd surely welcome any tips & insights as to the care & feeding of same. And as to CB trunks, are they typically constructed with thicker plating to compensate for reduced access for maintenance?

 

Any & all wisdoms on this would be greatly welcomed! Thanks.

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Use a corrosion resistant alloy perhaps? It also would be possible to put some UHMW chafe strips in the trunk to prevent rubbing.

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The chafe strips idea is one which ran through my mind too. How would you propose to attach them? I'd think that it would probably be easier to put them onto the centerboard, given that you can pull it out for maintenance. Plus it would be made of something not so easily eaten by the corrosion that goes with adding fastners made of a dissimilar metal.

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I've seen plastic of some sort printer on ever lift keel trailer sized boat I have ever been on. On the swing keels it was usually a large piece covering the while head of the board, and glued on. On lift keels it was strips, with csunk screws into the board case.

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It might be worth giving Alubat or Garcia or Boreal a call or email and asking them how they handle it - there are a ton of french aluminum centerboarders floating around so presumably they have something figured out that works - maybe it's as simple as just having extra heavy plate on the trunk walls?

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+1.

 

friend has a Garcia Passoa 47, his board has a raised radiused bearing surface, perhaps 50 cm out from pivot. Not sure what it runs against, but would not be surprised if rollers.

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Had some significant insights due to another post on this elsewhere, for those who care to see, or add to them. And one or two are Homer Simpson'ish in their simplicity. Kind of like the contact the company tip. Thanks for that BTW.

http://www.cruisersforum.com/forums/f55/centerboard-trunks-on-aluminum-boats-maintenance-questions-171312.html

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It depends on the builder. Most use some sort of plastic guide plates, that are durable and replaceable.

 

On our Ovni 435 we have three ertalyte strips that are mounted in aluminium channels on each side of the case. These are accessible (!) by removing plates in the top of the centreboard case for cleaning or replacement if they become worn. Boreal use something broadly similar but it's more adjustable. The strips are an interference fit and help to avoid any noise from the board when on the wind (for example).

 

The interior of the box is often unpainted as it would be almost impossible to maintain the coating or replace it, certainly with the board in situ. Apart from areas with lots of oyster growth fouling is seldom a problem, but obviously you have to deal with it at each haul-out. I have made a long flat aluminium bar that can be used to dislodge shells etc.

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On 8/29/2016 at 8:55 AM, CSpeedie said:

It depends on the builder. Most use some sort of plastic guide plates, that are durable and replaceable.

 

On our Ovni 435 we have three ertalyte strips that are mounted in aluminium channels on each side of the case. These are accessible (!) by removing plates in the top of the centreboard case for cleaning or replacement if they become worn. Boreal use something broadly similar but it's more adjustable. The strips are an interference fit and help to avoid any noise from the board when on the wind (for example).

 

The interior of the box is often unpainted as it would be almost impossible to maintain the coating or replace it, certainly with the board in situ. Apart from areas with lots of oyster growth fouling is seldom a problem, but obviously you have to deal with it at each haul-out. I have made a long flat aluminium bar that can be used to dislodge shells etc.

Cspeedie,

Currently looking at a used Canadian Ovni.  Curious what your experience with your 435 in cold water has been. Thinking about condensation in the bilge.  

Thanks,

Nat Smith

Houston, Tx

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