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Re: [bolger] Power/Sail Sail/Power Cruising discussion. Simple Jib-Stay Sail-Lateen rigs

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  • Kenneth Grome
    ... Why not use one or two crab claw rigs? They lift the hull rather than add downward pressure like most other rigs, and this would improve fuel efficiency
    Message 1 of 6 , Feb 1, 2008
      > So, whatcha think?

      Why not use one or two crab claw rigs? They lift the hull rather than
      add downward pressure like most other rigs, and this would improve fuel
      efficiency by making the boat lighter.

      Sincerely,
      Ken Grome
      Bagacay Boatworks
      www.bagacayboatworks.com
    • graeme19121984
      Hi Don, my two cents worth. I agree with you and think the concept is a worthy one, however the rig may be best left with dipping (SMS FMS), or balanced (MJ)
      Message 2 of 6 , Feb 2, 2008
        Hi Don,

        my two cents worth. I agree with you and think the concept is a
        worthy one, however the rig may be best left with dipping (SMS FMS),
        or balanced (MJ) lugs as originally chosen. Bolger went with these on
        bigger boats of similar motor-sailer, or powered sail-assisted
        passage intentions too, like on his own RESOLUTION, and the REIVER
        recently posted about here.

        These four-sided rigs are unstayed, with an easily lowered mast that
        makes riding out or motoring into a blow respectively more relaxed or
        fuel efficient. Also, any large true lateen rigs I've seen have been
        stayed.

        The rigs JG has shown aren't lateens however. They are staysails (big
        jib-like sail on rear set mast) with some similar desirable
        attributes of lateens in being a lifting sail, with a relatively low
        CoE for their size when fully deployed.

        Most photos I've seen of large lateen rigs reef to the yard; this, I
        think, due to it just being easier to tie the heavy materials of old
        to the lowered yard before re-hoisting, and the requirement to keep
        the decks free. JG's staysails are also shown furling upwards to to
        the stay. I see some issues here: the masts will be harder to design
        for the benefits of lowering them and the rig out of the wind
        altogether; the weight of the sail is raised aloft as reefing
        progresses (this may reduce rolling however, and even capsise by
        increasing the moment of inertia); and the CoE is raised with that
        reefing, when ideally it would be better lowered.

        Another attribute of the staysail is just that: it needs staying. I
        realise that JG has shown only sketched ideas, but IMHO there is
        rather insufficient staying shown - take a look at Bolger's STAYSAIL
        CAT (BWAOM, p149), or his staysailed CRUISING CATAMARAN (Derek
        Harvey's book or MAIB Vol9 N013) to see how much staying is required
        to stiffen the mast! The staying and stiff mast are required in turn
        to tension the luff.

        All that staying tension places great compression loads on the mast
        which the hull must resist - or the mast will be driven through the
        bottom, or the hull will "banana". This extra hull strength in turn
        may require the hull to be considerably heavier (and more costly in
        build and fuel) than otherwise.

        The common bermudan rig with main furled and poled out twin jibs from
        the single forestay is a well proven self-steering down wind cruising
        type. The lug may require just that bit more watching, but simple
        sheet self steering would even relieve much of that. Big lateens have
        to be watched carefully down wind as an accidental uncontrolled gybe
        can be disasterous.

        The lug and lateen are good reaching and not bad to windward.

        However, a lot of the above may not apply to your or JG's sail assist
        if the wind is often with you. The twin staysail rig shown by JG may
        not require all that staying, with the other inherent acccomodations
        I've mentioned, if it is absolutely to be used only for dead down
        wind work. If this is all it's to be used for then it won't matter if
        the luff sags somewhat, but sail assistance is given up for anything
        more than a very broad reach off the true wind. This rig may just be
        for the most refined of gentlemen ;)

        Regards
        Graeme



        --- In bolger@yahoogroups.com, "donschultz8275" <donschultz@...>
        wrote:
        >
        > So whatcha think?
        >
        > The neat thing I am writing about is that Jeff Gilbert has, in the
        > Yahoo group jgbuilders photo section, sketches of a couple of his
        > cats, Gravel Truck and Gumboots, using what he calls a lateen rig.
        He
        > sets the mast (masts) rearward and rigs a jib to it. The sail is
        > loose footed (no boom) and is intended for downwind runs only. He
        > suggests setting 2 of them, side by side, on his catamarans. Makes
        > sense based on his note below...
      • adventures_in_astrophotography
        Hi Graeme, ... ...snip... An excellent example of this is the America s Cup yacht that literally snapped in two and sank in seconds several years ago. I can t
        Message 3 of 6 , Feb 2, 2008
          Hi Graeme,

          ...snip...
          > All that staying tension places great compression loads on the mast
          > which the hull must resist - or the mast will be driven through the
          > bottom, or the hull will "banana". This extra hull strength in turn
          > may require the hull to be considerably heavier (and more costly in
          > build and fuel) than otherwise.
          ...snip...

          An excellent example of this is the America's Cup yacht that literally
          snapped in two and sank in seconds several years ago. I can't imagine
          wanting to pay for and maintain all of that rigging on a cruising boat,
          especially since one failure anywhere in the rig of even a single
          component could cause the whole thing to come down. I would love to
          try out a dipping lug someday.

          Jon Kolb
          www.kolbsadventures.com/boatbuilding_index.htm
        • adventures_in_astrophotography
          ... literally ... imagine ... boat, ... And here s the story: http://www.americascup.com/en/acclopaedia/boatdestiny/index.php? idIndex=0&idContent=2540 Looks
          Message 4 of 6 , Feb 2, 2008
            > An excellent example of this is the America's Cup yacht that
            literally
            > snapped in two and sank in seconds several years ago. I can't
            imagine
            > wanting to pay for and maintain all of that rigging on a cruising
            boat,
            > especially since one failure anywhere in the rig of even a single
            > component could cause the whole thing to come down. I would love to
            > try out a dipping lug someday.

            And here's the story:
            http://www.americascup.com/en/acclopaedia/boatdestiny/index.php?
            idIndex=0&idContent=2540

            Looks like I was off a bit - it took all of a minute and 40 seconds to
            sink.

            Jon Kolb
            www.kolbsadventures.com/boatbuilding_index.htm
          • donschultz8275
            ... The prime argument against about any other rig is that it adds additional spars to buy and handle, and learn how to use.
            Message 5 of 6 , Feb 2, 2008
              --- In bolger@yahoogroups.com, Kenneth Grome <bagacayboatworks@...>
              wrote:
              > Why not use one or two crab claw rigs?
              >

              The prime argument against about any other rig is that it adds
              additional spars to buy and handle, and learn how to use.
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