Crab Claw Riggung On Tri

Discussion in 'Multihulls' started by GOTTABSOMEWHERE, Aug 19, 2008.

  1. GOTTABSOMEWHERE
    Joined: Jul 2008
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    GOTTABSOMEWHERE Junior Member


    I HAVE BEEN ADMIRING "SHELLBOATS" CAT WITH THE TRIPOD CRAB CLAW RIGGING..........I WOULD LIKE TO INSTALL ON MY TRI BUT CAN'T FIND ANY DRAWINGS, FITTINGS, OR RIGGING INFO.
    SHELLBOATS DOES NOT HAVE A WEB SITE NOR PLANS FOR HIS RIGGING.
    CAN ANYONE HELP ME COME UP WITH RIGGING AND HOW DO YOU SAIL THAT THING ? WHEN I LOOK AT CRAB CLAWS, I SEE ALL KINDS OF SHUNTING RIGS, PRO STUFF ETC. ETC. BUT NOTHING SPECIFIC ON HOW TO MAKE THAT PARTICULAR DESIGN.
    ANYBODY OUT THERE HAVE SOME HELP ON THAT RIGGING AND SAIL ?
    THANKS IIN ADVANCE
     
  2. rwatson
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    rwatson Senior Member

    Just get some bendy trees and some tapa cloth, and follow your nose

    Except for looks, the Crab Claw on a modern hull wont achieve much.

    They only built them that way in the old days because they had to, and you always get some nostalgia buffs.
     
  3. kengrome
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    kengrome Senior Member

    Sorry, you're wrong about this. Fred Shell does indeed have a website, and here's his page about his Crab Claw Cat:

    http://www.shellboats.com/sbcrabclawcat.html
     
  4. rwatson
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    rwatson Senior Member

    I didnt thibk they were Crab Claw sails at Shell Boats.

    The real traditional ones - like at ...

    http://www.holopunicanoes.com/crabclaw.html

    Comments included .
    "The Crab Claw Sail is difficult to reef and the large amount of sail area up high tends to create lots of heeling force. It is not an efficient sail for reaching or going up wind."
     
  5. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Kengrome,

    Yeah He Has A Site But No E-mail
    I Talked With Him On The Phone
     
  6. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Thanks For Your Reply..............but Go To Shellbots And Look

    Don't Understand What You Mean When You Say "up High"
    Please Take A Look At Shellbots
     
  7. rwatson
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    rwatson Senior Member

    Yeah - I went to Shellboats and looked - and they are not 'crab claws'!

    The real 'Crab Claws' are the traditional Pacific sails that look like a tree with two branches, and cloth between the two branches.

    'Up High' means that all the sail is up in the branches, not down close to the hull.

    The Shellboat sails are just Lateen or Sprit sails with a boom, and most of the sail is down close to the hull where it doesnt try to tip the boat over
     
  8. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Rawtson
    So Ok........it's Not Traditional "crab Claw"
    I Still Like The Low Feature And It Looks Like A Easy Learner.
    Now...........what Is The Sail Size ?............etc. Etc.
     
  9. BWD
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    BWD Senior Member

    The tahiti/hawaii ones are vertical, most of the others are lower, some are adjustable.
    Micronesian proas are/were the champs, speed-wise, it seems.
    Personally I think the heavy tahiti & hawaii double canoes had vertical rigs to help keep steerage in the high seas they ran down in voyaging/migration between island groups. Maybe not so good on a modern boat 1/2 as long and much lighter.
    Here's one of my favorite pictures of crab claw rigs, from New Guinea.
    Look about and you can find photos of them with the sails hoisted to various angles, presumably some could be used in more than one trim.
    For a tri I might go with a short mast and flexible-tipped yards with adjustable stays, rather than a tripod. Having more flexibility to adjust it might help you find the best way. Plus you could have clearer decks when all furled.
     

    Attached Files:

  10. rwatson
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    rwatson Senior Member

    Beautifull shot there BWD - they obviously have fun with their boats, and no collar and ties ....

    GBSWHERE - you havt got a Tri you say?. What type, what size, has it got a sail already ? Can you post a picture?

    The size, type of sail, rigging have soooooooo much to do with the size, shape and style of the boat.
     
  11. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Rwatson
    17' Hobie Hulls...........16' Dory Between
    No I Don't Have A Sail.............trying To Make Like "shellboats"
    Have 16' Spars (booms ?)
    Have 8' A Frame..........stayed To Hulls Fore And Aft.
    Keep The Dialog Going
     
  12. rwatson
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    rwatson Senior Member

    If you converted a Hobie, you probably have the old mast and sails. If you dont, then you should be able to pick up an old set of rigging and sails secondhand for almost nothing.

    Just tie the bottom of the mast to the bow of the dory, move the jib attachment fitting near the top of the mast down to the say, a halfway position on the mast, and run a rope from the newly placed jib fastening to the top (apex) of your A frame.

    You may have to experiment on the position you put the jib fastening at, to allow for the current positioning of the A frame, and the space you have for the bottom of the mast to swivel about.

    Then you will have to cut some sails to suit the new shape of the mast. If you are clever, you might be able to put the old mainsail on upside down, so the bit that used to to be near the boom (foot) , is now the back edge of the sail (leech).

    Simple diagram attached that I hope will help.

    My recommendation, if you just want to get on the water ,is to stick the old hobie rig in the centre and save yourself all the trouble and hassle.

    You have to remember that these 'olden day' lateen rigs were built because they needed to create 'light' manouvarable rigs without all the advantages of modern fittings and metals. In practice, they require a lot more effort to get to work well, and are a lot more fiddly to use. Reefing is a problem for a start, and the foot of the mast has to be controlled as well as the foot of the sail.

    But, you will have fun experimenting, and learn a lot trying stuff out.
     

    Attached Files:

  13. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Hey thanks..........
    I like the idea of useing what i have but...........existing mast is 28" long.
    That would stick out the stern about 10'. Maybe I should "hacksaw off"
    about 10' from the bottom ? Mainsail dosen't have the right shape.............
    like the "crab claw" style.
    Another question (now that I have your attention) dosen't the sail/mast bump
    into the forward "A" support ........or tripod?
    I was going to use the Hobie's shroud line fastenting points (2 fore & 2 aft)
    to stabilize the "A" and not have a tripod mast like Shellboats.
    Cain't come up with a light ridgid "A", keeping with a homebuilt messabout....
    so I'm looking at 8" galvanized light weight fence posts. I am assuming the two spars........big sail........lines.........etc would be quite heavy and require
    an "A" of superior compression strength. Additionally, super strong/big
    deck plates to accomodate the "A"
    You are really helping my thinking...........
    OH by the way......Putting the old 28' Hobie mat in the traditional manner
    would give me the traditional problems of putting up the damn thing and taking it down. If the "A" is only 8' high I can trailer it down the highway
    with the sail lashed to the beams. When I get to the water.........simply
    crank up the sail.........yes?
     
  14. rwatson
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    rwatson Senior Member

    I wouldnt saw the mast shorter until you have tried it out.
    Like I said, you will need to recut the mainsail - hope you have a sewing machine :)

    yes, the sail/mast does bump into the underneath of the A frame (tripod) - as do the ones at Shellboats. A most unsatisfactory arrangement in my eyes, but hey - you are the customer :)

    You dont need stays for the A frame arrangement, or even a tripod. Remember, these designs were developed by resource poor sailors.

    If the foot of the main spar is tied to the bow of the centre hull, as well as to the apex of the A frame spars. it forms a tripod with the A frame.

    Likewise, if you tie the main spar to the TOP of the A frame (not hang it underneath), and make sure the track of the mast faces the sky when you insert the sail, you can actually pull the sail OVER the mast to the other side of the boat for better performance on the other tack (with the purple line). The old mast will flop back and forth on top of the supporting A frame as you change the sail side.

    Also, dont use steel pipe for the A frame. Get an old mast off some small boat and saw it in half. It will be plenty strong enough and a lot lighter

    All so much more work for a mast/sail setup that wont be nearly as easy or effective as the old Hobie rig, even on the 'modified' trimaran.
     

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  15. GOTTABSOMEWHERE
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    GOTTABSOMEWHERE Junior Member

    Understand your comments on spar material of "A" frame......
    Don't understand fixing main spar to bow. What you explain is nothing like I see on the "shellboats"
    Understand "resource poor sailors" but there is an evolution that is happening.
    "main boom on top of "A" ?????? You are kidding me right ?
    I know you AUZZIES are big on kidding the YANKS but really ???
    Please remember my point of not having to set-up and take-down 28' mast.
    I was about to suggest you change your brand of beer to BUDWEISER
    but BUD has been bought out by a Belgum company.
    Alas BUD is no longer a U.S. beer.
     
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