Coronado 15 Repair Help

Discussion in 'Boatbuilding' started by multivariablespace, Aug 1, 2017.

  1. Canracer
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    Canracer Senior Member

    Someone did this work already. Plywood strip and old glass removed.
    [​IMG]
     
  2. Canracer
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    Canracer Senior Member

    Epoxy and cloth can be very affordable if ordered on-line. The local marine store will charge a fortune.
    epoxy1.jpg

    I bought a full sheet of marine ply (3/8th I think) but only needed a half sheet. Get real marine plywood.
    marineply1.jpg

    Here's another look at how the compression post ties into the keel strip and the centerboard trunk. In theory it should all act like one solid structure.
    centerstrip3.jpg
     
    Last edited: Aug 7, 2017
  3. Canracer
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    Canracer Senior Member

    Building a compression post: That's probably your second project, after pulling out the damaged bulkhead. If you put on work gloves, you should be able to pull everything out by hand. It appears that almost nothing is holding the bulkhead in place. Go to town with a shop-vac and post more pictures (thumbs up, those were good images.)

    This part isn't rocket science. Approximate the size of the new post with a tape rule (and by looking at the old post), then cut a cardboard template. Use the template to mark out a piece of plywood.
    newstep3.jpg

    Test fit that first plywood piece and make adjustments as needed. When you're happy with the fit (should be about a 1/4" gap top and bottom) use that plywood part as the new template. I used 5 layers of 3/8" ply. Coat everything with epoxy and then thickened epoxy and clamp it together.
    newstep4.jpg

    I removed a little weight with a hole saw (probably not necessary) and used a 1/4" radius router bit to take off the sharp edges (also extra work.) Rounded edges hold epoxy better than sharp edges so in theory (and in non-theory) the part will stay waterproof longer (sandpaper would work fine.) The post was coated with a few coats of epoxy and then was ready for installation.
    newstep5.jpg
     
    Last edited: Aug 7, 2017
  4. Canracer
    Joined: Aug 2009
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    Canracer Senior Member

    Hey Multivariablespace, Are you a mathematics major? I haven't heard that term since my linear algebra class.

    There might be some confusion (on my part.) I interchanged the terms "mast step" and "compression post." I went back through my comments and corrected those mistakes and also misspellings and grammar errors.

    The mast step: As a result of movement side to side, and forward and aft, unchecked forces have damaged the sole of this cockpit. Not to worry it's fixable; I did see a hull where the step had eventually punched through.
    [​IMG]

    Under that step is a block of wood. It can be rebuilt to be stronger than factory. After the compression post is removed, the area under the step looks like this.
    maststep3.jpg

    Coat with neat epoxy and fill all the gaps with thickened epoxy.
    maststep1.jpg

    The plywood at the sides was sanded (prepped for epoxy) and then I put down a few layers of cloth. This area of the hull sees a ton of force so it can't be overbuilt.
    maststep2.jpg

    When the compression post was ready to install I used this stuff. It's expensive (around $25) but it's awesome. Different companies offer it now for less money so there's no need to buy West System. Thickened epoxy fills the gaps at the top and bottom of the post.
    maststep6.jpg

    Boom! Installed.
    newstep1.jpg
     
    Last edited: Aug 8, 2017
  5. Canracer
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    Canracer Senior Member

    Ok, maybe this information was helpful. Let me know if you have any questions. Add more pictures if you get the chance.
     
    Last edited: Aug 7, 2017
  6. Canracer
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    Canracer Senior Member

    Went back through my posts to correct some mistakes.
     
  7. multivariablespace
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    Location: Moses Lake

    multivariablespace Junior Member

    Fantastic! Great info. It's smokey and hot here so I've been getting some supply orders together. When the temps drop under 100 F in the evening I'll cut into the bulkhead and see how things look and post some more pictures. Thanks for the help.
     
  8. multivariablespace
    Joined: Aug 2017
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    multivariablespace Junior Member

    Started cutting into the bulkhead. It's kind of a bugger work space wise (I'm a bit reluctant to cut a hole in a perfectly good deck :)). The boat is on a trailer.

    Current mast support post seems inadequate to me. Once I remove the mast support post, do you think the deck is strong enough to keep sitting on it to work? I was debating if the post was supporting the deck as well.

    Do you think the boat strong enough I could crawl in the hatchway and sit? I started crawling in but could feel the hull flex a bit if I put weight off where the center support board used to be, and I wasn't sure if that was okay. I kind of worry about the stress concentrated at the trailer forward roller with me in it (I'm like 200 lb).

    It's kind of a tough call where to stop cutting stuff out. I really want to get it sailing by September and I don't have much time to work on it, so I'm thinking I'll just cut out the old mast support and rebuild that part and see if that will do it.
     

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  9. Canracer
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    Canracer Senior Member

    Nice work, and good pictures.

    That compression post looks like a solid piece of lumber (some are a lamination.) My understanding is that these boats were assembled with whatever materials were left over from the manufacture of the bigger boats in the company line. That compression post is definitely the result of someones creativity. Pretty cool.

    The adhesive that looks like concrete can be chipped away with a chisel and hammer. It won't crumble apart, but it will separate from the fiberglass. (Does anyone know what this stuff is?) Remove the mast-step screws before removing the compression post. I cut my original post in two and then it was simple to remove. Repairs were attempted on this post; with screws and epoxy and by adding new plywood to the sides, but the patches didn't hold.
    maststep4.jpg


    You can stack boards between the hull and the trailer, to support the area where you want to work (inside the bow.) With the boat on horses; this is a good way to work. I was able to work inside the hatch while sitting on the crate.
    hull1.jpg


    The forward side of the cockpit sole is supported in part by that compression post. After mine was removed I was careful to keep my weight aft, over the centerboard trunk.

    You will want to pull out that bulkhead to see what else is happening. The bulkhead is obviously destroyed and it's probably causing more harm than good at this point. Did you try the "just pull it out" strategy?
     
    Last edited: Aug 17, 2017
  10. Canracer
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    Canracer Senior Member

    The compression post holds the mast up, but nothing is stopping the post (and the bottom of the mast) from rocking side to side. That's what the bulkhead is for.
     
  11. multivariablespace
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    Location: Moses Lake

    multivariablespace Junior Member

    That upside down setup is a good idea. I've mail ordered some parts since nobody sells them locally, should be here in a couple weeks. I'll keep you posted how things go.
     
  12. Canracer
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    Canracer Senior Member

    What parts?
     
  13. multivariablespace
    Joined: Aug 2017
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    Location: Moses Lake

    multivariablespace Junior Member

    Epoxy. I put an order in with US composites.
     
  14. Canracer
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    Canracer Senior Member

    How's everything going?
     

  15. multivariablespace
    Joined: Aug 2017
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    multivariablespace Junior Member

    It's been kind of slow. I crawled in the forward compartment to work, but it was kind of cramped to get anything done so I flipped the boat over and have been working on removing the old mast support post and some of the rotten wood around it. It's awkward to get things done, I see why you cut into the top of the boat (I just can't bring myself to cut into a perfectly good deck yet).

    The centerboard slot has a weird overlapping plastic material. It's stiff and tears when I try and bend it, kind of like vinyl wall molding that has weathered. I"m kind of guessing someone decided to stop using it as a sailboat and clamped on a motor or something and covered up the centerboard slot. The material over the centerboard slot shouldn't be here should it? I'm thinking I need to tear it out and fill in all the screw holes with fiberglass. Inside the boat their are some wood slats that the screws go into, I think that is why they originally cut out the bulkhead.

    Thanks!
     

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