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Power/Sail Sail/Power Cruising discussion. Simple Jib-Stay Sail-Lateen rigs

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  • donschultz8275
    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,
    Message 1 of 6 , Feb 1, 2008
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      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.

      The following is from JGBUILDERS group, which is for those interested
      in Jeff Gilbert's catamaran designs. He supports the concept of low
      cost cruising w' motorsailers that are more motor than sail oriented.

      -----------------------------
      1. Mercenary thoughts on Sail versus power- the gravel truck etc.
      Posted by: "jeff gilbert" jgilbert@... jgilbert49
      Date: Thu Jan 31, 2008 3:18 am ((PST))

      Much to tell about the decisions that saw me wish to design a powercat
      which can sail, as opposed to a sailcat which can motor.
      The point is that many people own the latter, but use it as the former.
      When they add up their season's "sailing":, they find that an
      astonishing proportion of their on-water time is spent positioning
      themselves under power.

      The crew of "Sunstome" (40ft Spark Stevens Mono), tying the knot in an
      80,000 mile10 year circumnavigation, said in "Yachting World" that
      their most important piece of on-board equipment was their long-range
      fuel tank.

      Food for thought.

      Fuel may reach as much as 2 bucks a litre soon.

      The whole point about powering is that the fuel you use in your
      20-something-foot cruiser isnt creating the crisis. The crisis is
      caused by the showoffs who can't get on the water without a 1000 HP
      planing beast which consumes a average families yearly car supply in a
      day trip. They can afford it, but the planet cant.

      If you have a 20 -odd boat that needs 12hp to get along nicely at 6
      knots (say Gartsides "Wayfarer", or a Redwing) you have a choice, and
      you should use it.

      You can pay $10,000 for a lovely Yanmar and drive train and do it on
      just 3 litres an hour of Diesel
      You can pay $ 3000 for a nice 18HP Tohatsu 4-stroke OB and use 4
      lites an hour of gas.
      You can pay 500 bucks for an old 2-stroke OB and use 6 litres an hour.

      Which one, or which combo pays depends purely on how much you will use
      the boat, whether the diesel smell will piss you off, and reliability
      considerations. Remember an auxliliary OB isnt so much use if it uses
      different fuel from your main.

      Jeff
      ----------------

      One power option Gilbert leaves out is an air cooled lawn & garden /
      commercial engine, IE Briggs & Stratton or similar power. Yes, such
      gas inboards are a difficult to manage, because of fuel fumes, heated
      cooling air, and noise. But that's not my main point.

      Gilbert shares a philosophy similar to one stated many years ago by
      Bolger/PB&F. Also Jim Michalak in a recent newsletter, espouses a
      similar view that simple and less is better. I'm sure both Michalak
      and Gilbert are influenced by the senior Bolger.

      I have a copy of Bolger's "Folding Schooner" which has a chapter about
      a 25' motor sailer with outboard power. Bolger designed it for a
      contest. It won. In the essay, he says pretty much the same thing
      Gilbert says above about sailing a powerboat, rather than powering
      sailboats. Bolger followed this design with the 26' sailing Diablo
      that Bill McKibben built and named Ada. In BWAOM Fast Motor Sailer
      chapter, this boat is called the first Fast Motor Sailer. The 2nd and
      current FMS is an interesting boat with a full dipping lug rig. It is
      intended to sail OR motor, and Bolger is very proud of this boat's
      ability to do both pretty well.

      Bolger's SMS, small motor sailer with an inboard diesel and a dipping
      lug is also an interesting boat. It is not a completed design but a
      concept published in MAIB? In the essay, Bolger states he intends the
      diesel to be running all the time, with the sail rig assisting. The
      combination would yield high performance (always as fast as a World
      Cup racer?) and efficiency. SMS is a 22' boat. The implications of
      its design board efficiency translated to a Loose Moose size sharpie
      are interesting.

      The 100' Sir Joseph Banks in BWAOM is also a motor sailer which uses
      power 100% of the time with a sail assist. Again the intent is
      performance and efficiency. JB is intended to keep a delivery
      schedule at minimal operating cost.

      IMO, a Martha Jane, or the Delaware cruiser (Jochems Schooner hull) or
      most any Bolger sharpie could be rigged with the JG proposed Jib only
      rig. The lee boards could be eliminated or at least reduced in size.
      In an MJ, with the low CE of the Jib, I would go back to the original
      design water ballast only, but I would add the cabin, and keep the
      sponsons, even though they look odd. With a 10hp 4 stroke, water
      ballast and the easy to manage Jib only rig, it could be fun, cheap,
      and easy to motorsail with much more manageable trailering and storage
      than an 8' wide catamaran.

      So, whatcha think?
    • 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 2 of 6 , Feb 1, 2008
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        > 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 3 of 6 , Feb 2, 2008
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          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 4 of 6 , Feb 2, 2008
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            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 5 of 6 , Feb 2, 2008
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              > 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 6 of 6 , Feb 2, 2008
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                --- 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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