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Thread: Replacing crossbeam on Privilege Cat 1990's era

  1. #1

    Default Replacing crossbeam on Privilege Cat 1990's era

    Has anyone here replaced the crossbeam on a 1990's era Privilege Cat? Looking to get some ideas on process, costs and suppliers.

  2. #2
    Join Date
    Apr 2011
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    New Jersey and Cruising
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    25

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Hi, I was considering replacing mine. My plan was to take it off and mount it in a wood or steel jig to hold everything aligned. I would then cut, with a grinder, the extrusion off the end pieces. Buy a length of extrusion, notch the ends with the grinder and re-weld it in place. The cross bar extrusion is the same as the boom and the martingale is made from mast spreaders. All are from Sparcraft. http://www.sparcraft.com/ That way you're not throwing away the good pieces and you can get it the exact size by being in a jig. A good boatyard with a good TIG welder that you can trust should be able to handle the job.
    What happened to yours and where are you located? Cheers, Dave

  3. #3

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Boat's in Florida. A prior owner painted over the aluminum....

  4. #4
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    Oct 2008
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    Worcester, U.K., Moraira, Spain
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    567

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Quote Originally Posted by Lighthouse View Post
    Boat's in Florida. A prior owner painted over the aluminum....
    As far as I'm aware, every Privilege has the mast, boom and cross-beam painted white from new. It is a bit of a pain having to touch up every now and again but not sure I'd replace it just to avoid a bit of maintenance. Does it look corroded?

  5. #5
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    Jul 2009
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    Gosport
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    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    I would be very wary of just welding. Aluminum weld is weaker than the original
    material. I would look at fitting an internal splice and pop rivets.

  6. #6
    Join Date
    Sep 2014
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    Too far north to be comfortable.
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    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    In 2014: A selden forebeam for your boat would cost $6189 from Mack Sails, assuming the length of the beam is less than 6m.

    Cheers, and good luck.
    Paul.

  7. #7

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Quote Originally Posted by Jeannius View Post
    As far as I'm aware, every Privilege has the mast, boom and cross-beam painted white from new. It is a bit of a pain having to touch up every now and again but not sure I'd replace it just to avoid a bit of maintenance. Does it look corroded?
    Painting aluminum is always suspect - reduces oxygen and encourages corrosion. Anyway this guy put barrier coat on it. Yes, it is corroded.

  8. #8

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Good info. Thanks.

  9. #9

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Quote Originally Posted by quickcat49 View Post
    In 2014: A selden forebeam for your boat would cost $6189 from Mack Sails, assuming the length of the beam is less than 6m.
    Paul - Was that including install?

  10. #10
    Join Date
    Apr 2011
    Location
    New Jersey and Cruising
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    25

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Huh? The extrusion is currently welded to the attach plates. The martingale is welded to the extrusion. That is how it is made at the factory. The winch mounts are welded to the mast, the rigging tangs (the most higly loaded fittings on the boat) are welded to the mast, the topping lift attach point is welded to the boom. The spreader brackets are welded. I do not think that Privilege, who builds one of the strongest catamarans ever made, would make such a big mistake. Just my opinion of course. ...

    The reason that I was going to replace mine is that the crappy Amiot windlass shorted internally when the prior owner had it. This allowed voltage to travel down the anchor chain to the stainless forestay bracket. From there, it traveled into the crossbar and took aluminum with it on it's way to ground (the water). I had a few pits in the surface so ended up stripping the white paint off everything, dremeling them down, filling them with epoxystick, and repainting.

    When you strip the white paint, you will find that the anodizing on the extrusion will be missing where it has been welded. The aluminum should be painted to protect the aluminum or you will end up with corrosion. Be sure to etch the aluminum prior to painting.

    I'm not very good with costing projects since I do all my own work but I would think a newly fabricated crossbar would cost over 10 boat units ($10,000). A paint job is much cheaper unless there are structural issues.
    Cheers, Dave

  11. #11

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    my understanding is that paint inhibits the formation of protectant aluminum oxide and promotes the formation of corrosive aluminum hydroxide. I was a little surprised to learn this as I expected paint to be a protectant but some digging has unearthed a different perspective.

    Either way, I need to address the crossbeam. I was also guesstimating about 10BU.

  12. #12
    Join Date
    Apr 2011
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    New Jersey and Cruising
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    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Hi Lighthouse, I had my spars stripped and repainted in Mexico. The mast is raw un-anodized aluminum but the boom was anodized. When you have blistering paint, moisture sits in there and will eat the AL. I etched the AL with Alumiprep and Alodine and then sprayed it with Awlgrip High Build primer and Awlgrip White Topcoat. You could probably use Awlgrip Wash Primer CF as a prep but I preferred to have a chromium based etchant.

    I understand the aluminum oxide and chromium already exist prior to painting and the paint is there to protect that oxide layer. Similar to pickling and passivating your stainless. Crevice corrosion of stainless is caused from being in an oxygen free environment.

    Just another of my opinions but I feel that airplanes would not be painted, inside and out, if painting was going to cause corrosion. That's one place where corrosion can not be accepted, so why would they do it? There are a few shiny airplanes out there but not many. And, they are just shiny on the outside, not inside.

    You could also anodize the entire thing but painting is much easier and cheaper.
    Cheers, Dave
    Last edited by djdeakyne; 1st November 2016 at 03:53 PM. Reason: ammend thought

  13. #13
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    Sep 2014
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    Too far north to be comfortable.
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    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    That price was for the beam assembly, installation was not included in the quote.

    Good luck.
    Paul.

  14. #14

    Default Re: Replacing crossbeam on Privilege Cat 1990's era

    Coating with Nyalic is an alternative to painting. Much simpler prep and application lasts very well. I Nyalic coated our rig, it's still perfect after 6 years, 30,000 miles. You just wipe it on with a rag. Couldn't be easier.

    http://www.nyalic.com/Aluminum-Boats_c_42.html

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