Lock Crowther 1962 Kraken 25 trimaran build and rebuild log

Discussion in 'Multihulls' started by Corley, Jun 7, 2011.

  1. Corley
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    Corley epoxy coated

    I didn't really keep track I'm sorry but I'd estimate somewhere between 8-9kgs looking at the empty tubs. Actually that includes one float lamination as well but the surface area of the floats is pretty small and only double diagonal so that wouldn't make up much of the total.
     
  2. Marmoset
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    Marmoset Senior Member

    That's not so bad, approximately 2 gallons. I would have guessed more with it being basically 2 complete layers for 3 layers of strip. The amount of epoxy was the other reason I was considered earring strip method. I'd only be seeing epoxy to glue edges together then just a bit more for 3.5 oz cloth outside.


    Barry
     
  3. Corley
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    Corley epoxy coated

    If you're not too lax with your veneer fitments you use less epoxy. I got a bit slack with my middle layer of veneer and as you would expect noted an increased epoxy requirement for gap filling. The Gougeon's suggest prespiling all your veneers in each layer which is probably a good idea but since I only worked in small batches I spiled them as I went.
     
  4. Marmoset
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    Marmoset Senior Member

    That could be daunting holding all those pieces in place to smile it all! Maybe at 3 inch and larger it's more doable? And with no backer I'd imagine added wave in first layer would add to epoxy to adhere second layer, then third with nice back would take less. Will have to stew on it! Not tomorrow though! Bunch of us are renting a 40 foot cat to sail around sf bay. Perfect chance to see how I like a big cat.


    Barry
     
  5. Corley
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    Corley epoxy coated

    The third layer definitely takes less epoxy and gap filling as it's a pretty fair surface by then.
     
  6. Marmoset
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    Marmoset Senior Member

    Yeah maybe 1 layer of strip and then some diagonal strip? I know you usually have least 2 (or more) of opposing layers to lock it all in but maybe this small a boat I could do 3mm strip and a single of 3 mm diagonal. This would let me bag 2nd layer as well.


    Barry
     
  7. Corley
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    Corley epoxy coated

    In this skin thickness it's scarcely worth it probably best to stick with strip or if you wanted a more simple cold molded build go the double diagonal option. The downside is you would have to spend more time doing the hard turn to the bilge near the transom with double diagonal (I had to steam some veneers there even with thinner veneers used in triple diagonal) which would be more easily achieved with the strip method.
     
  8. cavalier mk2
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    cavalier mk2 Senior Member

    One double diagonal tip to remember is not to glue the edges of the first layer together. This lets the second layer lay flatter, glue is forced into the first layer seam when the second goes on. Be sure to wipe up excess inside to save work later.
     
  9. Marmoset
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    Marmoset Senior Member

    Yes I have thought about that a bit! I know between, harder to sand epoxy, and swelled wood, I don't want any loss of epoxy control above boards. I adhere 1 inch thick wood all the time and see swell, so at 2-3mm for sure! I know well that seams will all be sorted with next coat, and capillary effect will get it where it needs, so I don't have to sweat that. With more reading,and pondering! I think I know where they were headed with pre spiling. In a perfect world it would be nice to have first layer all fit and stapled, then epoxy and fit in 2nd layer in one go. Now before you saddle me up and ride me, Im just daydreaming here! Not saying i know just how to do that, but I do love a challenge.

    Barry
     
  10. Corley
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    Corley epoxy coated

    Building a laminated keelson and stem lamination would make the whole process easier if a little heavier. You would fair the keelson and stem lamination in situ once the mold is battened. Then you can fit all your interior hardware with certitude and since you fit the stem laminations in a rabbet it's easy to form and laminate the shape. When you lift the boat you are closer to completed than if you glass the two halves together. Neither method is especially difficult but having a fixed keelson just makes it a bit easier.
     
  11. Marmoset
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    Marmoset Senior Member

    yeah i definitely want all bulkheads, keel, and wales even in the layup from get go for a stable straight build. just don't know how to conjure that up without breaking out the epoxy. unless I had them in but foiled and waxed, then i could pop them up then back down after first 2 layers. then bag it all together with 3rd layer.

    Barry
     
  12. Corley
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    Corley epoxy coated

    I'd just leave them in and plane them down on the inside then glass with double bias inside and out only a minor increase in weight for the added dimensional stability. The alternative is just do what I did fair them flush with the mold and put a layer of plastic over your molds to prevent the epoxy getting a hold. I was able to break out the keelson and stem lamination quite easily after the hull was lifted.
     
  13. Marmoset
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    Marmoset Senior Member

    actually if you look at wooden boat schools cold molding page, they kinda show what i had in mind. 1st layer straight then 45 over that. that would allow easy bulk attachment and keel integration. could even do it "ala" Fife, and run layers close but not touching on a shaped keelson, then drop a 1" keel and stem in the gap, then shape final at end.

    Barry
     
  14. Corley
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    Corley epoxy coated

    A little work over the last week on the main hull. I've installed the deck beam gussets and made some rough patterns for the bulkheads. There are three bulkheads in total one to handle the loads from the genoa one for the front crossbeam and one for the rear crossbeam. I might put one at the rear deckbeam behind the daggerboard case to enclose a small area for storage in the centre of the boat where there should be enough room to fit a small hatch for storage of a picnic blanket and lunch out of the way for when we are daysailing. A minimal increase in weight and makes the boat a little more practical when taking the family out.
     

    Attached Files:


  15. Marmoset
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    Marmoset Senior Member

    looking good! with that coat of epoxy on inside you can see the nice color of that wood. Has keel been poured yet?


    Barry
     
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