what wood should I use

Discussion in 'Multihulls' started by kim s, Jan 27, 2010.

  1. kim s
    Joined: Apr 2009
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    kim s Junior Member

    OK, Before any-one says "OOOO I would not do it like that" I know its not the best but money, time is starting to become an issue.

    I have a hartley design Sparkle 28. the AMAS are laminated planks.
    4no ---- 9" x 3/4" planks --18' long laminated together.
    I have the formers to build them etc. I am looking at ally poles, box section, carbon,etc but keep coming up against a wall, so looking at resorting to "as designed"

    I would like box section but would need some-one to design and give me the design ( I would pay) as I again i understand the princaple of it but wouldnotknow where to start on thickness and internal structure

    There is no indication on the plans as to the best wood to use.
    I did thin of laminating with Uni fibres inbetween the planks.
    The mast cap shrouds go out to the Akas and there are water stays.
    so please can any one advice as to the best strength to weight ratio.and what would do the job .

    Kim
     
  2. gonzo
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    gonzo Senior Member

    If you are building "as designed" why not use what the design calls for??
     
  3. Paul B

    Paul B Previous Member

    Reading is FUNdamental.
     
  4. Gary Baigent
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    Gary Baigent Senior Member

    Kim, the Hartley Sparkle is not a wide trimaran (but quite heavy) and therefore your beams just have to do the job, and they don't have to be especially high tech. A suggestion off the top of my head, going from past suck and see education, would be to make box sections to the 18 feet x 9 x 9? inches dimensions of Hartley's original beams, (did you write that there are four beams? - anyway I'd go to two decent boxes) using one the very best wood and that is Port Orford cedar in planks (and strips if you want to be refined with a more aerodynamically shaped main beam) of half inch thickness, then epoxy the interior. Build two x two sides, or three x one side, then glue together and then wrap two or three layers of box weave 10 oz glass around the (rounded corners) of the beam. Remember you also have water stays and they do a lot of good work. Get the Gougeons' book. Don't load your boat down with heavy junk - less weight equals less loads on the beams. Paul B is being unusually polite with the gonzo journalist.
     
  5. kim s
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    kim s Junior Member

    If looking could erase the ink, then I would have a lot of A3 sheets of blank paper.
    There is no reference to them at all.
    there is the spec for the ply, the frames then just a description of the dimensions for the Amas.

    Hence my plea for help. or even a reference book I could read or anything.

    Its getting warmer and I need to get cracking

    Kim
     
  6. DarthCluin
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    DarthCluin Senior Member

    I have a set of "Lively 28" plans I bought through ClarkCraft. I think this is the same boat, and neither the plans or the material list recommend what kind of wood should be used for the crossbeams or iakos. I also have Hartley's boatbuilding book, and while it has an exhaustive list of Austrailian, New Zealand, and British boatbuilding woods, none of them are designated as suitable for the cross-beams on their trimarans.
    If you got your plans through Hartley, email Hartley. On their website they claim to provide free help while you build.
    http://www.hartley-boats.com
    If, like me, you got your plans through ClarkCraft, email Clarkcraft. They don't make the same claim, but its worth a shot.
    http://www.clarkcraft.com
    There aren't that many pictures of the Lively 28 out there, but what few there are seem to show that the crossbeams flex under load, like a leaf spring, or a bow, but that also might just be variations in individual builds.
     

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  7. kim s
    Joined: Apr 2009
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    kim s Junior Member

    what wood to use

    Darth,
    I believe they are one and the same and yes i got my plans from Clarkes but good idea will try and email both. they can only ignore me:confused:
    I do have the gougeon bros book and did not spot what I wanted. must get time to read properly.
    Its the flex bit that does concern me as the way I read the plans, the design is using the cap shrouds and the water stays to tension the whole boat. I suppose that is why the rigging wire is 8mm shrouds which on the face of it is a bit excessive, but if its to take the shock loading of waves hitting the hulls then ---well I suppose it will be alright. after all they claim its the first multihull to circumnavigate Australia!!
    Are you going to build her? I am re-building an old one. would have been quickerto start again I think, oh well 70% of the ply replaced just the outer hulls left to re-deck. roll on some sunshine.

    Gary

    Thanks for the advice. The original beams are 18ft x 9" wide x 3" thick. (4 x 3/4") If I understand correctly, its the depth of the side pieces in a box section that realy give it the strengh. and at only 3" that is going to be difficult. I can build deeper sections, but only to a max of 6" as it then starts obstructing the companion way.. without MAJOR surgery to the Hull to drop them down, this would mean cutting out a bulkhead and re-strengthining the hull,
    I think if I go for a light timber with layers of uni-strand glass epoxied in between, as you noted, sheis not very wide and the water stays are there.
    I understand that using Hard wood is not perfect due to the fact it does not soak up the epoxy as well. But its more rot resistant, so if I coat it in epoxy to prevent the water ingress, then who knows. Its just this nigalling problem of the best wood to use, Ceder,pine, iroko, spruce,Oak even ( just got to chop the tree down in the garden and wate a few years)
    Thanks for the input so far. its a shame there does not seem to be any one hear with one (hmmmm I wonder why)

    Kim
     
  8. Gary Baigent
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    Gary Baigent Senior Member

    Kim, 3 inches depth is too shallow. If you can go to the maximum of 6 inches, go for it. I don't know if in the UK you can get kiri (paulownia) but that is a plantation tree in NZ ... very light, very high strength figures for its weight - and it WONT rot. Port Orford cedar is also a plantation tree here and it has the best figures of all woods. There is also planked balsa (if you can locate some decent lengths) which is also way up there on strength to weight figures - and you can saturate it with epoxy so rot is no problem. IMO don't go for the heavy and dense timbers. If you are really worried about stiffness (and if you go to 9 x 6 inches you are going to get a good stiff box) laminate the mid beam length sections in layers of uni directional carbon.
     
  9. peter radclyffe
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    peter radclyffe Senior Member

    if you cant get port orford, maybe you can use western red cedar or spruce, from robbins, or timbmet
     
  10. DarthCluin
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    DarthCluin Senior Member

    The short answer is no, I will not be building her.
    When you first start looking at multihulls, the Lively 28 is a very tempting boat. It can be an attractive boat. Tolu Vaa looks elegant. The design is demountable, so transporting it from the building site to the water involves a lot less drama. The plans are a steal at $75 and include full size patterns. The design has an impressive history, and ClarkCraft offers frame kits, epoxy kits, and fastener kits for this specific design. If there doesn't seem to be a lot of them, I think it is simply because it is an old design that was just never as popular as a Piver or a Cross on this side of the planet.
    Why did I decide not to build her? First I found a set of plans for a Piver Nimble on the Classic Multihull website. The plans are no longer there, though there are still scans of Piver Stiletto plans and partial scans for Nugget. Nimble is probably more boat than I am interested in, but I liked the design enough to get a set of 25' Mariner plans from the Mariner's Museum. Then, oh the pain, oh the pain, I found the Buccaneer 24 threads on boatdesign.net. I guess this is how plan collections start.
    Meanwhile I am making progress on my Dierking Wa'apa Tri, shown here bolted together so I could plane my chine logs.
    Hey! For what it's worth in my copy of "Building Outrigger Sailing Canoes" by Gary Dierking, under Choosing Materials for an Outrigger Canoe (page 5) it says "Laminated cross beams can use cedar in the inner layers with a harder wood like fir or mahogany on the top and bottom." In Chapter 9, "Cross Beams and Hull Connections" (page 113) there is more, "Choose the timber carefully using only pieces with straight grain and very small tight knots." Please bear in mind that this is a canoe book. You might want to get a copy, as it has a lot of boatbuilding information.

    http://groups.yahoo.com/group/classicmultihullsailboats/
    http://www.mariner.org/
    http://www.boatdesign.net/forums/multihulls/buccaneer-24-builders-forum-28496.html
     

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  11. DarthCluin
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    DarthCluin Senior Member

    The laminated beams shown on my Lively 28 plans are are built up like a leaf spring pack, whereas Dierking's are a constant section. I think if you use a stronger wood on the outside, it might have to run the full length of the beam on the top and the bottom. Dierking also glass tapes the ends of his beams to prevent splitting. Your boat is much bigger and heavier than a canoe, so I really don't know how well any of this would work.
     
  12. kim s
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    kim s Junior Member

    Thanks guys for all the input,

    Gary

    Thankyou for the info on the wood, I will go to my local timber yard who do seem to be able to supply EVERYHING. All the old classic sailing Smacks and old Thames Sailing Barges all get their timber from there

    I believe they do have good quality ceder so will make enquires next week and go and inspect it. from whatthe general feeling is coming back, is that it does not seem to matter too much what is used as long as its good straight grain and knotless (is there such a word?)
    If only I could afford the carbon, then I would have the whole thing done. I spat my coffee over the keyboard when I got a price for carbon I wanted to do another project. I do know then, there was a shortage and so prices went through the roof, maye the price has dropped. Yes I know in the grand scheem of things compared to the cost of the rest of the boat, its not a large percentage, but!!!
    I could get carbon I suppose, its just I have a lot of expense on at the moment as my car cracked the head and so bang went my boat money:(

    Darthcluin.

    Ilike the idea of usng a lighter wood in the middle, so creating a box section(ish)
    I must admit, looking at the Nugget ----of bugger. I did not want tostart building from scratch and iI only ended up with the Lively becouse I found her rotting in a creak. In fact I had to put pictures up here on the Forum to find out what she was.
    And like know, you guys have come up with the goods.

    Thanks again

    Kim
     
  13. gonzo
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    gonzo Senior Member

    I thought you were trying to completely re-engineer the beam. Do you just want to know what species of wood to use? The same as for spars is good. That is: spruce, pine, fir.
     
  14. kim s
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    kim s Junior Member

    Thanks Gonzo,

    sorry if I may have led you astray but as I tryed to say in the first posting, I would like to re-engineer the design BUT I keep coming up various brick walls. design, cost,etc so hence go back to "as designed" , But it is very interesting that there is no standard answer which I was hoping there was.
    But now you and others have pointed me in the right direction and now I just need to investigate what the local timber supplyers has available
    Thanks again one and all

    Kim
     

  15. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Beams are spars, so you can look at any information on masts and booms for calculations or lumber types.
     
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