Valiant 40 refit - marine ply substitute

Discussion in 'Fiberglass and Composite Boat Building' started by TINHO DORNELLAS, May 11, 2017.

  1. TINHO DORNELLAS
    Joined: Dec 2010
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    Location: Merritt Island

    TINHO DORNELLAS Junior Member

    Hello , I am in the process of doing some repairs on a valiant 40. Around the chainplates and on the rear cabin, I had water intrusion that in some cases rotted out the 5/8" plywood that is used to screw teak battens that hold the ceiling panels. The plywood ribs glassed to the sides of the hull are used to hold the wood slats that decorate and finish the boat sides. I will have to replace these .
    Some of the plywood ceiling "cleats" (I do not know the proper term for the wood screwed to the fiberglass, to which the ceiling panels and battens are screwed) have black mold and I am replacing them, not just because of it but at the edges they lost some integrity.
    The picture shows the "cleat" around the chainplate knee. I have three questions.
    IMG_2836.JPG
    1- Can I use radiata pine instead of the marine ply to replace the "cleats" , as well as the ribs that will hold the wood slats. I have used this wood and it is very solid and takes screws better than fir in my experience. Locally it is difficult to find 5/8" marine ply.
    2- The surface veneer on the knees was badly delaminated from water intrusion, so I removed it. inside you can see the 1 1/4" Ply knees which look solid. I don't see wood rot in the holes. they seem well tabbed to the hull and ceiling. But I planned on enlarging the holes and filling them with Epoxy/cabosil mix, then re/drill. You can see the two top holes have elongated. Is this a good solution? I am trying to avoid having to cut and re-glass a new knee
    3-The surface veneer ply that flaked off and rotted, is about 1/8". I plan on ending up with a white surface instead of the Ash veneered covering that covers most of the cabin sides and bulkheads. is the best solution to add a formica covered 1/8 ply or any other solution I don't know of?
    Thanks in advance
    I added a curiosity picture just in case anyone has questions about crevice corrosion on chainplates. 4 out of 8 where cracked in half, with substantial cracking all over the place. These are 3/8" thick chainplates.
     

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  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Plywood is more stable than solid lumber for your cleats (yep, that's what they call them). 1/2" plywood will do just as well as 5/8" for these and is easy to find. In fact you can save some money and use 1/2" MDO, which is available at many sign painters or some lumber yards. 3/4" plywood will also do, with a very small weight increase (maybe a pound total). It'll just space it off the hull shell another 1/8", which might hide some imperfections and paint lines too. Additionally, you can use "Exterior" rated sheathing, found at the local big box store. Both of these are APA rated PS1-95 which is the marine grade, just cheaper. Be careful to get exterior, not "exposure 1 exterior" which isn't APA1-95 rated.

    As for a decorative finish, well there are several approaches you can make; more veneer, high pressure laminate over some 1/8" plywood, simply fairing and smoothing under paint, etc. I haven't been on one of these in years, but you have to admit they looked good veneered.

    Lastly, I'll guess your boat was early to mid 80's and the chain plates haven't seen any serious service since they were installed. We see this fairly commonly and it is a real concern as you've found. Still plenty of service from the installation method.
     
  3. TINHO DORNELLAS
    Joined: Dec 2010
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    Location: Merritt Island

    TINHO DORNELLAS Junior Member

    Thanks a lot for the response. Unfortunately it is really hard to find any decent lumber around here. I will keep searching. Since all other cleats butting against what I am replacing are of that thickness less or more thickness would create a step.
    This particular boat was used in a race I think it won a big name race, and the original owner was pretty serious about racing. The later owner did many trips up and down the coast but then the boat sat for 5 years.
     
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    There's lots of places for marine supply in your area, which is not all that far from me. Florida is the country's largest user of plywood, so supplies, inventories and types are plentiful. 5/8" marine isn't common, but 5/8" in APA1-95 is. Getting a precise thickness match will be difficult, because thickness requirements have changed since your boat was built. I'd use the bonding glue to space it off the hull shell any extra distance that might be necessary. If you want the "good stuff" you can drive down to Vero Beach or come inland towards Orlando. Have your tried "Bob K's Marine Supply", off highway 1 in Cocoa?
     
  5. TINHO DORNELLAS
    Joined: Dec 2010
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    Location: Merritt Island

    TINHO DORNELLAS Junior Member

    Par, I have not tried Bob K's but located some marine ply in Vero Beach. Also I measured and I was wrong. The main cabin cleats are 3/4" so I am all set. On the Vberth they are thinner, but there also I decided on a different material - Endurabond. Remembered today that stuff is great for having fasteners attached, bonds great to epoxy and will NEVER rot. Why didn't I think of this earlier....And as you say, I can space it to match the rest.
     
  6. UNCIVILIZED
    Joined: Jun 2014
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    Location: Land O' the Great Lakes

    UNCIVILIZED DIY Junkyard MadScientist

    You can buy lumber that's thicker than you need, & then plane it down to the proper thickness. Or have the lumber yard run it through a thickness planer to the same effect. That, or you could buy some 1/2" plywood, & glue on some 1/8" stuff, to get you up to 5/8". And is it essential that you use plywood for your cleats? They'll be (pretty much) out of sight anyway, so I'm not sure that anyone would even notice if some of them are solid lumber, while others are plywood.

    That picture of the delaminating plywood is troubling, as it would have me wondering if it will delaminate more in the future. As well as whether or not both it's glue bonds, & the fibers of the wood themselves, have become degraded deeper inside of the wood. So that it may appear fine, & not be soft when poked, but still be greatly lacking in structural integrity. I hope that that description makes sense.
     
  7. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    It never ceases to amaze me when I see chainplate systems like this on a boat like the Valiant 40. The chainplates on my 6000#, 1963 Cal 28 were about three foot lengths of silicon bronze, 3/8 thick and 3" wide, with about 20 1/4 bolts in each one. And they weren't buried under any veneer, just bolted to the main bulkhead for all to see. 50 years without a leak or squeak or egged-out hole.

    This picture from a magazine gives you some idea, but my boat had a different interior and the plates extended down about another foot to the seat cushions. This boat is 1/4 the displacement of the Valiant.

    [​IMG]
     

  8. TINHO DORNELLAS
    Joined: Dec 2010
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    Location: Merritt Island

    TINHO DORNELLAS Junior Member

    WOW long chainplates! My only thought is the Valiant has 4 chainplates per side and loads are distributed through them even though the rear ones carry the bulk of the load. I am pricing out Titanium chainplates as they have a much higher tensile strength and none of the corrosion problems of the stainless.
     
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