Aftmast rigs???

Discussion in 'Sailboats' started by jdardozzi, May 28, 2002.

  1. DennisRB
    Joined: Sep 2004
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    Location: Brisbane

    DennisRB Senior Member

    Nice thread! I was in Perth recently and I saw that cat. I didnt know it had a mast that could be lowered, but it makes sense as Perth has a some great waterways all blocked by low bridges. What design was the yellow cat?
     
  2. Spiv
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    Location: The Big Wide Blue Brother

    Spiv Ancient Mariner

    The current owner broke the original rotating, lowering, carbon mast and replaced it with a much cheaper, fixed alloy mast. So now he cannot do river charters.

    The design is a Schionning Cosmos 12.5, but I changed the roof to give me more space inside. The boat has a day charter complement of 40 pax.
     
  3. DennisRB
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    DennisRB Senior Member

    Cool. I had it pegged as a Schionning. Something like that would be ideal.
     
  4. brian eiland
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    You are exactly correct Stefano, and as you try to raise and lower an even taller mast the problems gets worst,...it really tries to go sideways (either side). I was working one one solution on our Firefly trimaran that involved splitting each shroud into two 'arms' (upside-down 'Y')to be attached to outboard ends of the crossbeams on both the front and rear. The aft 'arm' was actually rigged as a running line inboard to a small winch that could be adjusted as necessary to keep the mast (36 feet) going up straight.

    It also simplified adjusting the rigging's tension, and tied the structural components of the vessel together nicely, rather than just thru fiberglass hull components.

    Newick's Somersault as used a similar shroud attachment.
     

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  5. Spiv
    Joined: Jun 2007
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    Location: The Big Wide Blue Brother

    Spiv Ancient Mariner

    The key is to have the two side stabilizing lines anchored 'in line' with the mast pivoting pin.

    I solved the problem by attaching two lines to the middle of the spreaders and tying the other end to the top of the raised daggerboards using 2 block and tackle for tensioning.
    it was a little 'springy' as the daggerboard flexed a little, but even on a 19m mast, the load was not large.

    I had two 5m poles going from the bottom of the forestay to both side of the coachroof, they provided the fulcrum needed to lower/raise the mast over a certain angle.

    I then had to swing the boom out of the way and used an electric winch (the type you use on the front bumper of 4wd vehicle) to raise and lower the mast.
    I'd also changed the galvanised wire with spectra.

    The mast rested on 'crutches' until it was raised again.

    Once we got good at it, it took us 15~20min to get from sailing to be ready to lower the mast, then just 1min to lower or raise it.
     
  6. brian eiland
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    brian eiland Senior Member

    That of course was a good solution, but it was not to practical on that trimaran with most all of its 'attachment points' well below the level of the mast pivot point.
     
  7. brian eiland
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Carbon Fiber Furling Gear

    Just doing a little research this morning into some of the more recent tech in carbon fiber forestays, particularly furling ones, and wanted to just record some of the links so I would remember to return for review.

    http://www.carbo-link.com/furling-cables

    http://www.maxspar.com/alu_carbon_genoa_profile.htm

    http://www.facnor.com/uk/products/custom_products/carbon_headsail_furlers/default.asp

    Perhaps I could make use of 3 carbon fiber stays in combination with a carbon fiber mast to eliminate some of the differences in expansion between dymeen and alum, and carbon that can result in the need to 'retune' the rigging in different climate conditions.
    http://www.briontoss.com/spartalk/showthread.php?t=2156
     
  8. Kojii
    Joined: Oct 2006
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    Location: Ensenada, BCN

    Kojii All is remodelling

    Latest location Relentless -bought by a fisher

    Relentless, a North Pacific 47' experimental delta rig with aft bipod mast, designed and built by Fred Greenway, now in Newport, Oregon, one of the busiest fishing ports on west coast. Also gets kinda windy along that stretch. Yet the furcula remains intact (if shortened from original).
    Let the wild speculation begin...
     

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  9. brian eiland
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    brian eiland Senior Member

    A few more pics of that model I unpacked not long ago...
     

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  10. brian eiland
    Joined: Jun 2002
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    brian eiland Senior Member

    ...and a few more
     

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  11. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    I went trying to locate this fellow Claudio, only to find my 'subscription' to that RC Sailing forum had expired,...so I am reapplying as I see this fellow Claudio is still quite active on that model boat forum.

    Does anyone know if he ever participated in this or another forum??
     
  12. markstrimaran
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    markstrimaran Senior Member

    Thanks for the rc link. I might have my boat sailing soon. Mounting amas or akas today.
     
  13. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    more Bolger's Staysail (mast aft) Rig

    Just looking around the internet a few days ago I ran across another photo of Bolger's experiments with an aft-mast arrangement,...this one with a full wishbone boom that reminds me somewhat of Dave Beirig's single-sided wishbone, 'CamberSpar'.

    I have given thought to attaching my mizzen's wishbone boom directly to its 'forestay' rather than to the mast. :?:
     

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  14. Kojii
    Joined: Oct 2006
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    Location: Ensenada, BCN

    Kojii All is remodelling


  15. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    FUNNY :D

    ...lets add an image to that posting of yours Kojii
     

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