Small trimaran with Tornado/Nacra 5.8 center hull

Discussion in 'Multihulls' started by revintage, Dec 25, 2021.

  1. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Hi Solgato,
    Thanks for the tip, although that type of surplus is not available in Sweden, as we don´t have any airplane industries. Have actually thought of making my own sandwich flat panels with fiberglass, epoxy and 10mm 80kg for the floor and Divinycell 60kg for the side panels. Already have it in the workshop. Not as light as honeycomb though, but a lot cheaper. Want to make everything demountable, so thinking of using aluminium profiles to build a frame. Did this sketch yesterday, showing the rear of the main beam center tube. Open at the rear and closed in front.

    Curious, have you sorted out your mast rotator issues?

    cockpit45.png
     
    Last edited: Feb 21, 2023
  2. SolGato
    Joined: May 2019
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    Location: Kauai

    SolGato Senior Member

    Found that link. It’s a US supplier, but it’s interesting to see all the sandwiching options available.

    https://www.carbon-core.com/

    Regarding my rotating rig, yes I think I’ve figured out how it was originally rigged.

    The designer and folks who spec’d the mast and sails knew what they were doing.

    Somewhere along the line between owners the knowledge of how it was supposed to be rigged did not get passed down which explains why the last few only had it connected to the boom.

    I will be making up a pair of 2:1 purchases similar to jib sheet control lines and running them aft through the clutches so I can lock the mast.

    There isn’t a lot of room above the spanner to run the line you suggested to keep it from pivoting down as the boom yoke attaches and the sail gets fed into the track just above, so I may instead fabricate a ridged under support that anchors to the mast with a turnbuckle for adjustablility so long as it doesn’t interfere with other control lines.

    Anyway, I have a plan now and will know/learn more once I get the boat rigged and launched this Summer.

    Thanks again for your input on that.
     
  3. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Cooled down a little about the design of the cockpit, as it was a real overkill. This shallow version will anyway give some sailing dinghy feeling and something to stand on when hoisting the sails.
    Found Exalite at an importer of packing material in town. Durable polypropylene panels, that only set me back 25USD/sqm. About the same weight as the planned epoxy panels at less than half the material cost. Well below my 15kg limit.

    exalite.png
     
    Last edited: Feb 24, 2023
  4. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Slowly making some progress. Built the side walls for the cockpit, but realized they where clumsy in the lower corner and also a little to deep. Have just picked up the PVC profiles for correcting them. The trampoline will be swept around the side tubes to the keder rail and will be made with a pocket for 8mm EVA for comfort. Initially I will use the Nacra rear beam with 100x2mm extenders to get 4.7m beam. The sketch shows the side wall redesign, that also saves more than 500grams. Sailing weight is calculated to be max 250kg.

    golv9.png IMG_1948.jpeg IMG_1949.jpeg IMG_1952.jpeg
     
    Last edited: Mar 27, 2023
  5. Forecaddie
    Joined: Apr 2023
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    Location: Brisbane Australia

    Forecaddie Junior Member

    What do you use for documentation drawings? Nice work on everything. I am looking at building a power tri.
     
  6. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Actually it is the old MS Paint. I am to old and lazy to learn something more advanced;).
     
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  7. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Some tiny but important details added. At last the new forestay and waterstay fittings are installed. The front and rear waterstay fittings are bolted on each side of the beam bulkheads and the forestay bridle(35cm) M10 fittings are bolted in the heavily reinforced hullsides.

    Last minute change: Dumped the old Nacra rear crossbeam and changed back to the new one in 100x3/90x3mm with bolted 2.5m Harken track. Changed beam from the initial 4.6 to 4.8m. Adjusted sketch below.

    Hulls, beams and the small rig(F18, Tornado jib) will hopefully be tried together next week and I am hoping to test sail in the beginning of July.

    IMG_2450.jpg IMG_2451.jpg IMG_2459.jpg IMG_2413 2.jpg IMG_2447.jpg

    221212balkar2.png
     
    Last edited: Jun 7, 2023
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  8. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Finally it begins to look like a tri. Made beam 15.75 ft but will probably go down to 15 ft. The nose down might be to steep, easy to fix as I have one inch lower spacers for the rear beam in the workshop.Unfortunately a few strap threads are stripped to the rear of the akas, will go from 5/16" to M10 and replace all eight. The center hull has brass but the akas have aluminium inlays.

    A few weeks back it was to hot to work outside, now it is almost to wet.

    tri.jpg
     
    Last edited: Jul 8, 2023
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  9. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Began building the rig. Had to dig deep in the Frankenpart box to find useful items and prepared the upper diamond tangs for T-terminals. Also built a lower removable hinge for the old Capricorn F18 mast base. Spreaders and hounds are from the same mast and only needed minor adjustments to fit the almost 40 year old NOS Marström mast tube. The Nacra 20FCS swiveling mast hook is also prepared to fit. Only ca 40 blind rivets away from ready[​IMG].

    Staying home today, splicing the Dyneema standing rigging, using Hampijan DynIce Dux for the waterstays and forestay, SK78 Teufelberg for the four shrouds and Liros D-Pro Static for the diamonds.

    båtmast.jpg stuff.jpg tang.jpg hinge.jpg open.jpg up.jpg nacra-mast-hook-swivel.jpg
     

    Attached Files:

    Last edited: Jul 18, 2023
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  10. SolGato
    Joined: May 2019
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    Location: Kauai

    SolGato Senior Member

    If you don’t already have a pneumatic rivet gun, I highly recommend getting one.

    Much less violent (especially setting stainless) and easy on the hands and wrist when you have more than a few to do.

    And you get a much cleaner install since you only have to pull a trigger, versus ones tendency to twist as they use a manual setter.

    CEB3B112-431D-4918-A285-AF595A11A6F9.jpeg F894A10A-41E3-4725-8190-910A65A5F7F6.jpeg 1A6CA4EE-B724-4B92-9B32-A71B6AD93A66.jpeg
     
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  11. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Thanks SolGato! My budget doesn´t allow a pneumatic, but I have a heavy duty tool that makes it easy to rivet 4.8mm stainless. Plus I don´t have to bring my compressor when working at the beach.
     
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  12. Air Tahiti
    Joined: Aug 2023
    Posts: 18
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    Location: South Carolina

    Air Tahiti Junior Member

    Revintage - I am new to the forum this is post #1. I just took possession of one Tornado hull and two Nacra 5.5 hulls. The mast is Tornado. I am looking to begin this project in late 2023. I have another much larger project mid stream, home addition. Please keep the info alive and I should follow your path by about 6-12 months. My goal is to build a stable but fun platform to sail on lakes when camping in my RV. I have 5 kids. At this point performance isnt critical. I have found a set of old tornado sails, and have some leads on cross beam material. I plan to cut the tornado hulls top out and spread it out a bit. Then add some flooring and bench seats as typically done on small tris. Who knows how it will turn out but I am determined to see it through and have the green light from the mrs.
     
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  13. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

  14. revintage
    Joined: Nov 2016
    Posts: 414
    Likes: 101, Points: 43, Legacy Rep: 10
    Location: Sweden

    revintage Senior Member

    Prototyping a beach trolley, but will turn it around with two larger swivelling wheels, 3.00-4/260x85 instead of the tiny 2.50-4, to the rear. Will also use it for transporting the boat on my trailer. Question is if hanging on the main beam as shown or resting on rolls along the bottom of the hull is the way to go?

    IMG_20230817_163233.jpg

    IMG_2708.JPEG
     
    Last edited: Sep 4, 2023

  15. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Reinforced the main beam by adding a 1 m 4" lower tube with 1/8" wall thickness.
    Added UV-protected surfaces to the Exalite cockpit sidewalls.
    Next step is installing the EVA covered cockpit floor.
    Due to the present invasion of mosquitos (Aedes cinereus) you have to work fast:eek:.

    sidewall.jpg overall.jpg
     
    Last edited: Sep 7, 2023
    BlueBell likes this.
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