Wood for a new mast

Discussion in 'Boat Design' started by SV Papillon, Dec 24, 2006.

  1. SV Papillon
    Joined: Dec 2006
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: lake union

    SV Papillon Junior Member

    Would Silverbali be suitable for building a spar out of?

    Silverbali

    I'm asking as I need to replace a mast on my 50' schooner. I'm in the PNW and going off of other posts and advice from our architech consultant Sitka Spruce and Douglas Fir seem to be the ideal choice. I'm buying a bunch of silverbali for the boat refit and thought I should throw it out there.

    Thanks

    Jake
     
  2. Raggi_Thor
    Joined: Jan 2004
    Posts: 2,457
    Likes: 64, Points: 0, Legacy Rep: 711
    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    Spruce is stronger in the outer fibres than close to the center, ttat may be an important detail in mast building,
    see http://cat.inist.fr/?aModele=afficheN&cpsidt=16908566
    "The stiffness modulus in the longitudinal direction for Norway spruce grown at a medium-fertility site increased with distance from the pith from 6±1 to 8.5±1 GPa."

    Density of silverbaly seem to vary a lot.
    Maybe you should check the properties of the batch you are buying.
    If it's a hollow mast you can probably adjust wall thickness in a linear relation to the stiffnes ratio.

    Hav you asked the architect?
     
  3. BOATMIK
    Joined: Nov 2004
    Posts: 303
    Likes: 18, Points: 28, Legacy Rep: 190
    Location: Adelaide, South Australia

    BOATMIK Deeply flawed human being

    I agree - ask your architect.

    The critical factors are usually

    1/ How well the timber glues - timbers can appear to glue OK but sometimes it is not as good as it seems. One of the reasons we generally stick to Fir and Spruce is because their properties and quality are pretty well understood with the result that we can predict the behaviour of structures made out of them.

    2/ Its density - as strength and stiffness vary in line with density for most timbers.

    3/ Its grain pattern - you want long straight grain - not grain wandering in and out of the sides of the boards.
     
  4. SV Papillon
    Joined: Dec 2006
    Posts: 6
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: lake union

    SV Papillon Junior Member

    Thanks for the input. I have not run it by the architect yet. I would assume a similar response. I'm rather naive in this, just looking for different alternatives. Getting a suitable length for a solid spar would be cost prohibitive, I guess spruce or fir it is.

    Thanks,

    Jake
     
Loading...
Similar Threads
  1. pironiero
    Replies:
    24
    Views:
    6,353
  2. laukejas
    Replies:
    47
    Views:
    13,169
  3. Tom Dugan
    Replies:
    7
    Views:
    862
  4. hashtag_laeuft
    Replies:
    20
    Views:
    1,386
  5. leecallen
    Replies:
    16
    Views:
    3,780
  6. hashtag_laeuft
    Replies:
    18
    Views:
    3,340
  7. Steveso
    Replies:
    28
    Views:
    4,223
  8. the brain
    Replies:
    12
    Views:
    5,769
  9. boatboy123
    Replies:
    14
    Views:
    2,241
  10. the brain
    Replies:
    5
    Views:
    3,044
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.