Main-less rig

Discussion in 'Multihulls' started by Spiv, Feb 10, 2008.

  1. brian eiland
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    brian eiland Senior Member

    That's the one. I misspelled it above, leaving off the 'n'.
    http://www.lightningclass.org/

    I picked that vessel as I have always liked their looks, and I believe I could step my mast right at the tail end of the centerboard trunk with a little extra reinforcing.

    And there are lots of them out there to trial horse against.


    Agreed

    My concerns as to cost are secondary to what might be possible as an alternative sailing rig for a cruising vessel, and performs admirally well.

    I'm coming up on 70 ;)

    BTW, did you work directly with Lock Crowther at one time?
     
  2. Spiv
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    Spiv Ancient Mariner

    Hi Brian,

    I had one of them; in 1976~'79 I cut the transom off, sprung the last two ribs opened, lengthened it by 1.5m, built a cabin, built a steel bulbous keel and my proudest built was a fully glued (no screws or nails) tapered, spruce mast!!

    I sailed it with my wife-to-be and my two brothers, from Rome to the island of Ponza (~100NM) for about a week, then migrated to Oz.

    Had I known then what I know now, it would have had an A framed, 3 furlers rig......and two hulls :D


    Yed I have, interesting indeed.
     

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  3. brian eiland
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    brian eiland Senior Member

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  4. Fanie
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    Fanie Fanie

    Well spotted Brian !

    Note the booms on the sail foot, these make handling the sails easy. The booms are set up about correctly, the sail foot will taunt automatic when the boom in swung in and make a lot more power dumping aft and not downward.

    The sail of the future...

    Nice boat.
     
  5. Fanie
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    Fanie Fanie

    I would like to comment on the diesel inboard on the 3rd page of the 2nd link.

    There is a good chance the diesel may already be replaced with an electric motor. Remember to date the biggest problem were the batteries... Well, it still is :D BUT, there is a major improvement already, if you look at the LiFoPo4 batteries, they have some very advantageous properties over the previous available batteries.

    If you can fit enough solar panels, and when the higher efficiency panels become available, all this energy problems will be a thing of the past. These LiFePo4 batteries can be charged to ~80...90% full in ~20 minutes, they can be run flat, have a cycle life of better than 2000, or 5 years and more, they are less than half the weight of current batteries and more improved advantages. The price may still be a ripoff though, but certainly offers an advantage in that while you sail the panels will fill the tank.

    The current solar panels are only about 12.5% effective, they are however already at ~37% with a different technology, and some developrs claim they may see 60% and more not too long from now. Considering there are around 1000W per sq sunlight, that 60% and more can make for substantial energy available.

    Them bastrd developers are going to wait until we are dead before they come up with the nice stuff.... :(

    And if your are not going to succeed in getting rid of these demonic democrats, be prepared to pay per watt sunlight you use.
     
  6. oldsailor7
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    oldsailor7 Senior Member

    YES. And if the CIA had not sequestered all of Nicola Tesla's work after his death we may well now have unlimited electric power for very low cost.
    Have no doubt about the fact that the great Coal, Oil, Gas and Nuclear conglomerates have the financial and political power to crush new developments which may affect their financial bottom lines. :eek:
    If the big powers had put as much money and effort into researching Zero Point Energy, as they did in developing the Atom Bomb, we would have unlimited low cost electricity today. But of course the car manufacturers, together with Gas and Oil are petrified at the growing advent of electric cars. :rolleyes:
    Rant over. Back on Topic.:)
     
  7. Spiv
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    Spiv Ancient Mariner

    I am always thinking about "A" frames...
    The ability to have the mast hinged at the bottom and be able to lower them to go under bridges being one of my driving concerns.
    I wander if rotating foils like this would suit an A frame rig?

    This ketch rig provide lower clearance and probably be OK in the Intracoastal with 18m clearance, but many other waterways around the world, have low bridges that seem to provide only an average 7m clearance.
     
  8. oldsailor7
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    oldsailor7 Senior Member

    John Hitch had (or still has) a big catamaran which has an aft positioned mast with three forestays and twin backstays which only supported the mast.
    On these he could rig a varying array of foresails to be very efficient on any heading. Sorry I don't have a picture, :eek:
     
  9. brian eiland
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    brian eiland Senior Member

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

    These were a couple of variations I drew up for a wishbone shaped aftmast rig:
    http://www.boatdesign.net/forums/boat-design/wishbone-sailing-rig-1999-3.html#post109336

    Its been quite a while so i might have to re-review them for possible changes. i know I have changed the orientation of my forward jumper struts in later dwgs...to place them directly in line with the aft jumper strut.
     
  11. Spiv
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    Spiv Ancient Mariner

    Yes, I remember all that Brian.
    Are we ever going to stop designing new rigs.....??
     
  12. Pericles
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    Pericles Senior Member

    Aft mast ability without the mast being aft.

    Spiv & Brian,

    I've gone around the houses with reference to sails. I have the "Bridges of River Thames" to contend with. I am looking at a standing/dipping lugsail, (depends whether I have a crew) with a 12 feet tall freestanding mast & a yardarm of about 20 in length for a flat bottomed skiff with waterline length of 19 feet & waterline beam of 6 feet.

    An Sulaire is the only full size Sgoth Niseach remaining & was built in 1994. Jubilee is a three quarter size vessel built in 1935. These boats were fishing boats crewed by hard men. They had to be fast to get the catch to port & easy to work for line fishing, so the entire rig would stowed within the boat, whilst the crew were fishing. With the wind on starboard the Lateen type sail has a very tight luff & the sail draws without being affected by the mast.

    http://www.falmadair.com/jubilee.htm

    For cruising along the Thames, I envisage loosening the halyard to rapidly drop the peak of the lugsail from 24 feet above the water down to the height of the mast at 12 feet & then haul it up again, once the bridge is cleared, is an outcome devoutly to be wished.

    http://thames.me.uk/s00780.htm

    It's that or out with the quant pole. Not a pretty sight. :p :p :p

    http://en.wikipedia.org/wiki/Quant_pole
     

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  13. Spiv
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    Spiv Ancient Mariner

  14. sigurd
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    sigurd Pompuous Pangolin

    roller reefed main

    A gap between the mast and the main stay is mostly only undesirable depending on geometry. If the mast extends behind the stay it can be desirable (higher lift, more tolerant of AoA excursions). The mast, or a sleeve around it, is rotated for the other tack.
    There will always be some sag in the stay. This would mess up the small slot geometry. Hence the stay is supported by protrusions along the trailing edge of the mast.

    The slot could be optimized only for a narrow angle of attack range. Maybe this is a tradeoff someone is willing to make for a furling rig that can go somewhat to windward.

    On the other hand better adjustability would be possible if the stay attachment points were to be pivoted as well.

    The section is a Speer series 3 proa section.
     

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  15. sigurd
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    sigurd Pompuous Pangolin

    Do you need to discard a freestanding mast for going under bridges?
    Picture this example: The mast stub stands on a tripod. The front two feet of the tripod are hinged on for example the roof of a cruising cat. The aft leg is normally bolted to the roof but can be used to winch the mast forward and down.
     
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