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Re: [bolger] Re: Cartopper - rudder details and centreboard pivot

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  • malcolmf
    ... Bill Kreamer wrote It s hard to picture the snotter causing the mast to rotate much, what with the friction at partners and step. Can someone with a
    Message 1 of 14 , Aug 29, 2008
      nsimms wrote:
      >
      > --- In bolger@yahoogroups.com <mailto:bolger%40yahoogroups.com>,
      > malcolmf <malcolmf@...> wrote:
      > >For a sprit
      > > controlled sail to function correctly, the mast must be free to turn.
      > > If it didn't turn, the sprit & snotter would wind or unwind around the
      > > mast on different tacks, giving different tension to the sail.
      >
      > Is this really true? I'm in the middle of building the leg o'mutton
      > rig for a modified Nymph, and the Nymph plans seem to show the
      > (square) mast wedged into the longitudinal thwart (which acts as a
      > mast step), at the mast base.
      >
      > So I made my mast step (I have no thwart due to my customizations)
      > such that the mast will be tapered/wedged in at the base and will not
      > turn. It will thus be 'suspended' and kept off the 1/4" ply bottom of
      > the boat. I haven't constructed the mast yet, so it's not too late to
      > change this if the mast absolutely needs to rotate.
      >
      > Anybody else have experience with the small Bolger sprit rigs? Does
      > your mast rotate or not?
      >
      > BTW, I was planning to make the snotter a la Dynamite's 'Instant
      > Boatbuilding' book, and as 'alternate' spec'd in the Ruben's Nymph
      > plans, with a thimble in a sling, through which the snotter passes.
      > IIRC, Dynamite says this method is less prone to binding.
      >
      > Seems to me this ought to work freely enough not to require rotation
      > of the mast...
      >
      > Neil S.
      >
      > P.S. Looking more closely at the Ruben's Nymph plans, it appears the
      > mast on that design IS free to rotate, being round at the base, with
      > the weight of the mast bearing on the partner via the mast chocks. Of
      > course that's a bigger rig (59 sq ft vs 40 sq ft on Nymph). So now I'm
      > not so sure which way to go :(.
      >
      >
      > No virus found in this incoming message.
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      Bill Kreamer wrote
      It's hard to picture the snotter causing the mast to rotate much, what with
      the friction at partners and step. Can someone with a big-ish snotter/sprit
      rig chime in? Maybe greased leathers in those areas would help. And a
      retaining collar clamped around the mast under the partners? - Bill K

      Hi, all,
      My boat is a 16 foot, 6' beam, FG Crawford Dory, weighing about 450
      lbs. I have two sails that I use: a 77 ft sprit and a 99 ft sprit. The
      mast is a round, glued up mast, about 3" diam, tapering aloft, no
      leather, greased or otherwise. I have been sailing this boat for about
      17 years now.
      There are undoubtedly other ways to do it, but as far as I know the
      standard rigging for a spritsail is all on the mast. I assure you that
      the mast can rotate in its step. I scanned some passages out of John
      Leather's "Spritsails and Lugsails" and offer some of his comments:

      /"The hole in the mast thwart should not fit /[and here I lost some text
      in scanning]/ chafing piece of greased leather seized or sewn around it
      to allow the mast to rotate in the step, which is desirable with small
      spritsails."
      /

      /"The sprit is set up by passing the tail of the snotter through the
      score in the sprit heel and then through the thimble, forming a purchase
      which is swigged-up until wrinkles are thrown in the sail from tack to
      peak, as in setting a gaff sail."/

      When the sprit pole is 'swigged-up', the tension (and it is
      considerable) is set relative to the mast. Since the pole is offset to
      one side of the mast, if the mast did not turn, tension would change
      when tacking and the sail, pole et. al. go from side to side. In
      tacking, the mast does not come about all at once, rather it walks its
      way around under the influence of the snotter and the movements of the
      boat. Turning the mast by hand is not difficult, but it does take both
      hands. /

      /

      /"The spritsail, mast, sprit and rigging is best first tried laid out on
      the ground. The clew should be high and the tack low. Spritsail masts
      should have good rake as this seems to help the sails set well and
      usually improves the appearance of the rig in a small boat. Many small
      spritsail boats had adjustable rake on at least the mainmast."
      "The thumb cleat for the tack might be fitted just above the upper mast
      support, as low as possible, to allow adjustment of the tack position.
      The thumb cleat for the snotter is best positioned on the ground with
      the sprit 'peaked-up' at its correct angle to set the sail. This cleat
      should be as low as possible. The robands should be tied to the mast,
      not too tightly."/
      /"When everything seems satisfactory on the ground, the sail can be
      furled for carrying or stowage by taking the sprit out of the snotter,
      placing it parallel to the mast and, keeping the head of the sail taut,
      throw the clew over the sprit, then roll the sail and sprit up to the
      mast, maintaining an upward pressure on the peak so it will furl
      tightly. The loose snotter is passed around the sail and mast and then a
      clove hitch is passed around all. The sheet is coiled and made fast to
      the tail of the snotter. The rig is then ready to be carried, stepped or
      stored."/
      /"A long narrow boat will probably be best with a rig of two or more
      spritsails. It is usually best to make these sails of different areas,
      with the larger as the foresail and the smaller the mizzen in a two
      masted rig; or the mainsail larger than the foresail, and the mizzen
      smallest in a three masted rig. If two masted, the full rig can be
      carried in light winds and in stronger breezes the foresail can be
      reefed. If the wind strengthens, the mizzen might be furled and
      unstepped and the foresail be shifted slightly aft in a second step, to
      preserve sail balance. This step can usefully give increased rake to the
      mast. In strong winds the mizzen, only, could be set up, probably in the
      same step and well raked. This reduction of sail area and a freshening
      wind will usually require the centreboard to be lowered further. In the
      now uncommon three masted rig the mainmast and sail is the first to be
      furled or struck, leaving the fore and mizzen as a useful area for
      stronger winds. If wind strength increases these are reefed or shifted
      for the two sail rig."/

      These passages show that the entire sprit rig can be set up outside of
      the boat and easily be picked up and shifted about. I cannot remember
      where I read it, but I have heard that just chucking the entire rig over
      the side (but not losing hold of the sheet) makes a wonderful sea anchor.


      /"When beaching a spritsail boat in a light onshore wind the sails can
      be allowed to rotate to blow out forward; this is possible with the
      rotary masts but undesirable in other conditions as retrieving the
      sheets and retrimming the sails would be difficult afloat.
      Alternatively, in a two masted spritsail boat, the mizzen is handed and
      the foresail is brailed up as she runs for the shore."/


      This is a step that I commonly take. I agree completely about
      difficulty in retrieving the sheets and retrimming sails when afloat,
      but it is a long way from being impossible. In gentle weather it is OK
      just to unsnap the sheet from the sail, allowing it to blow out forward,
      while you catch a fish, eat lunch or attend to other business. With a
      bit more wind, getting all together again can be a chore and something
      that I would not care to recommend trying in a tender boat. Care does
      need to be taken not to get the sail wrapped around the mast.
      /
      "A sizeable sprit rig is not ideal for single-handed sailing, as to go
      forward and unship the sprit from the snotter by hand is not easy if the
      sprit is to leeward of the sail, and it may be difficult if it is to
      windward, as once the heel is out of the snotter it tends to drive down
      and could pierce the bottom of the boat in extreme conditions, when it
      is best to direct the heel overboard."/
      Ya' gotta be careful. And I agree completely with him here. I
      sometimes think that a lug sail would be easier to use. All you have to
      do is loose the halyard, and if the spar doesn't brain you on its way
      down, the sail is in and you can do the housekeeping later. With the
      sprit, you have togo to the mast, undo the snotter; the sprit heel
      going overboard gives you more room and makes life easier. Then while
      keeping the peak of the sail in check, get the pole inboard, then roll
      the sail up to the mast. To furl I use a line for this that has an eye
      in one end. Run the line around the mast/sail, put the bitter end
      through the eye and spiral the line down the sail and secure it. If
      everything is calm I use marline hitches, otherwise just spiral it down.
      Then you can take the mast down. I grew tired of lifting the mast/sail
      over the partner, so I installed a pair of hinges, replacing one if the
      pins with a cotter pin, then cut the partner in half so I could hinge
      the partner open. It helps.
      All of this being said, I really don't know what ground rules apply for
      a leg o' mutton rig with sprit boom. And I am sure that many sprit rigs
      have worked well without a rotating mast. Good luck on whatever you
      choose to do. There's always more than one way to skin a cat.
      Calm Seas & A Prosperous Voyage
      Malcolm





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