Wood equal to or better than Douglas Fir?

Discussion in 'Materials' started by abosely, Jul 1, 2015.

  1. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,926
    Likes: 888, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    That radiata is horrible stuff nzboy, surely not much use for boats ?
     
  2. nzboy
    Joined: Apr 2011
    Posts: 154
    Likes: 4, Points: 18, Legacy Rep: 36
    Location: nz

    nzboy Senior Member

    Yes I agree radiata is not that flash .But some of the high density export grades that the average chippie never sees are quite nice .So I would default to silver beech (which is beautiful ) and some of your ironbark jarra for a rub rail .While we do have supplies of douglas its not every mans cup of tea to work with. The stuff which my ladder and yours was made of was American oregon which has a fine grain compared to our 60 year old plantation stuff But yes there are boats here being fitted out with radiata
     
  3. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,926
    Likes: 888, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Yes, I suppose all I have seen is the rubbish Radiata, not the choice stuff.
     
  4. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    PM sent...
     
  5. Angélique
    Joined: Feb 2009
    Posts: 3,003
    Likes: 330, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    Last edited: Jul 6, 2015
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 481, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I don't have much on Monkeypod other than the published attributes, except it apparently is an irritate when breathing saw dust. Sounds like it might be a closer choice.

    Yes, you can decrease dimension sizing to take advantage of different species physical qualities, though a lot of the time a few fractions (or mm) is all you'll get, so often not worth the bother, unless it's a lot of material, such as the hull shell or spars. I regularly make Douglas fir spars and will knock 15% or more off external dimensions, bringing it more closely in line with the spruces typically employed, but with much better fastener pull out and stiffness attributes. In a spar, light is very important, but cabin sides, not so much.

    Troy, Jammer is one of those folks that stands on something, but is unable to justify or defend. He's a "barker" and likely a Donald Trump fan, because as everyone knows, both are taken seriously.
     
  7. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    PAR, just to double check the suitability of Monkeypod based on available data, compared to D-F.

    Monkeypod D-F
    Hardness 900 620
    Rupture 9,530 12,500
    Elastic 1,149,00 1,765,00
    Crushing 5,790 6,950

    I don't know the relative values of these numbers or really how they apply the my use.

    From what I can tell Wharram didn't design the structures to a fine edge. As he knew people would need to use local woods sometimes for building.

    Quote from James Wharram
    "Timber availability and costs may dictate the use of different timbers from those specified in the plan. I can only advise you to use common sense in choosing timber, and attempt to match the characteristics called for in the Plans."

    If Monkeypod would be suitable, it has several advantages, very low shrinkage & easy to dry, easy to work, plane & sand, said to take finishes & glue well, can get bigger, longer logs, so less splices, have more material to pick from to choose the lighter pieces.
    Not to mention that Monkeypod one of the prettiest woods!

    So what is your recommendation about using Monkeypod? I will of course use good judgement in selecting the lumber to build with.

    If Monkeypod is a go, I'll start gathering logs!

    Cheers, Allen
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 481, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    That's roughly what I have. Basically what the real comparisons are:

    Douglas fir is about 18% lighter, about 30% rupture and 40% better in rupture and elastic modulus, with about 17% better crush strength. Simply put, Monkeypod is harder, but weaker in every other regard comparatively. This in itself isn't a bad thing, though some adjustment might be desirable with certain structural elements. If this is a Wharram design your doing, you could probably leave things (dimensionally) alone with few worries.
     
  9. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    Yes, it's a Wharram Classic. Still debating on whether to build the TangaroaMk IV or Narai Mk II. Most likely (99%) will be the Narai Mk II.

    Stringers are 1"x3", most of wood is 1" thickness.

    When it comes to the crossbeams, I would like to pay you to look at them & see if anything should be increased in size, just to be sure since they are a critical component.

    Actually I would like to have you look over the plans before I cut lumber to dimension. Just to be sure nothing should be increased in size.
    Not a stress analysts, but look it over to be sure all is good.

    I want her to be as rugged as possible and be totally safe structurally for sailing in any weather. Not that I want to be in bad storm weather, but as a blue water sailboat sometimes it happens.

    Would you recommend using Monkeypod or Albizia Lebbeck for construction?
    Or possibly a combination of the two. Maybe Albizia for crossbeams or some other higher stressed components. I don't know which would be the higher loaded parts tho.

    Cheers, Allen
     
  10. Jamie Kennedy
    Joined: Jun 2015
    Posts: 541
    Likes: 10, Points: 0, Legacy Rep: 117
    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    I love his designs. Would love to try one out some time. What a terrific boat for Hawaii, functionally and aesthetically. Have you had a chance to sail either one or both to help you decide which one?
     
  11. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 481, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I think you can use either or both. It's probable you'll employ both, as you come across it. Agreed Jamie, it's the perfect island boat, particularly Hawaii. Drop me an email if you like (click on my icon).
     
  12. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    Jamie no, I don't know if there are any Wharram's around here. Especially on the Big Island. Yea, it's a pretty awesome place for sailing, fishing, freediveing, spearfishing etc..
    The shallow draft is a big help too.

    Cheers, Allen
     
  13. Mr Efficiency
    Joined: Oct 2010
    Posts: 9,926
    Likes: 888, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Love those Ono ! (Wahoo)
     
  14. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    Yes true PAR, off the top of my head probably use Albizia for keel, it's laminated wit 4 layers of 1" planks. Two before sheathing & two more after sheathed. That makes it nice for using shorter planks & scarfing them. Can really stagger the scarfs.
    And the stems fore & aft, their laminated also, but won't need scarfs for them as their short enough.
    These two two areas are nice because they are down low so most of the weight is low.
    Plus probably the laminated cross beams too.

    Depending on your recommendations when the time comes, PAR.

    Cheers. Allen
     

  15. abosely
    Joined: Mar 2015
    Posts: 136
    Likes: 1, Points: 18, Legacy Rep: 10
    Location: Big Island Hawaii

    abosely Senior Member

    Oh absolutely! Ono is... Well Ono! :-D
    And Ahi!
    Had some fresh Ahi for lunch earlier this week. Just pan seared the outside, sliced it thin with some Teriyaki & a local sauce. It was Ono!
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.