NZ 8.5 m rule

Discussion in 'Multihulls' started by Steve W, Oct 28, 2012.

  1. Steve W
    Joined: Jul 2004
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    Steve W Senior Member

    So ive just been reading the rule and it seems very sensible and seems to get quite a few boats on the line, i think it was smart basing it on the GBE and am wondering what mods have been done to the existing boats to make them competative, the obvious one is the plumb bows which would add a lot of volume fwd, any other hull mods? any have wider beam?, are the rigs taller or are they just running high tech sails on the standard mast? I noticed the rather outstanding performance of Whio in the coastal classic. I cant help but wonder if something similar could not be done here in the US based on the Stiletto 27.

    Steve.
     
  2. jamez
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    jamez Senior Member

    Some explanation of GBE Mods in this thread here
    http://forums.sailinganarchy.com/index.php?showtopic=137516&hl= 8.5 gbe mods#entry3801055

    IIRC masts are stock height but some now have larger sections to cope with the big squaretop mains that most 8.5s have.
     
  3. HASYB
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    HASYB Senior Member

  4. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    Seems like quite a few boats are using wingmasts, are these alluminum or carbon? anyone building there own? Sparcraft has a section F175c 204x98x3.8kg/m, this is a bit heavier than the original GBE mast at 3.59kg/m but maybe not more than if they are using bigger than original sections. Any of the GBEs increased the beam? I would think that if you plumbed the bow by lengthening the waterline you would end up changing the forefoot depth a bit otherwise the knuckle would be quite a bit above the waterline at rest, not necesarilly a bad thing but i dont see this in any of the photos ive seen.
    Ive read the sailing anarchy thread and i just cant see why the aussies think they need a taller rig, what, do they think the kiwi boats would be slow over there? It seems to me that as long as all boats stay within the box the racing will be fair,regardless where you sail, the goal after all being to have your own start and not neccesarily be racing against the an arms race.
    I would love to see the NZ rule adopted, as is over here in the US.
    Steve
     
  5. jamez
    Joined: Feb 2007
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    Location: Auckland, New Zealand

    jamez Senior Member

    I'm not aware that any GBE's have been made wider. The masts are a mix of alloy and carbon, mostly fairly standard sections. Tigre originally had a glass/ply/carbon wing but now has a more conventional section.
    You can find some boat reviews here
    http://www.multihull.org.nz/85-class/?Section=8.5 Reviews

    Incidentally the Stiletto 27 you refer to already fits the 8.5 box rule with a little room to spare all round, bit like an F82 does.
    I don't think it would matter what rig height was allowable, a rule that doesn't measure sail area is always going to encourage the biggest sails that can be fitted. When the GBE was designed in the 1970s its rig height (12.6 airdraft) was probably considered a little extreme (then carrying about 40 sq metres up wind), but even higher aspect rigs seem to have become the norm over the last 20 years or so where mast height is not a consideration. Currently the biggest 8.5 rigs are setting up around 60 sq metres of working sail upwind. A tall narrow rig is supposed to be more efficient, but most of the 8.5s seem pretty quick with what they've got.
     

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  6. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    In order to get something going over here it would probably make sense to modify a Stiletto by plumbing the bows and extending the transoms to get to 8.5 as well as increasing the beam, it would be nice to shave off the stupid looking cabin and build something better looking with more space. I dont know the air draft is but widening the beam would allow one to up it to the class max. It would also need daggers in the hulls. The plus side is there were about 300 of them built so there are always a few for sale and they were a very high tech build with nomex honeycomb core, epoxy prepreg, oven cured and i believe painted rather than gelcoat, this would be high tech today so at only about 500 to 600 kg stock ther is plenty of room to make your mods and still need corrector weights.

    Steve.
     
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