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

    Thanks ttlf,
    This gave me an idea:cool:. Can´t wrap the beams, as I might want to reverse build and go back to a beachcat with 5.5 hulls and 3.2m beams. Anyway thinking of adding 1.5m cups made of 110x2mm tubing, cut in two halves to be fitted to the center hull. The cups are 106mm inside, that could be built up with epoxy and glass, to fit the 100mm beams. It can easily be done in one layer, using this 660gr cloth/chopped mat. EDIT: Added simple sketch with table of estimated added strength. Note the cups will be clamped at the ends.

    [​IMG]

    beamload.png

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    Last edited: Jan 18, 2022
  2. revintage
    Joined: Nov 2016
    Posts: 344
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    Location: Sweden

    revintage Senior Member

    Finally found a donor for the center hull. Got this odd Tornado for free, but it will be perfect for my build. Haven´t seen it IRL, will pick it up mid-April, 550km from home. Looks like an early 70´s GRP Sailcraft/Reg White UK. A friend of mine will take the other hull and probably build another tri.
    upload_2022-1-25_13-4-22.png
     
    Corley likes this.
  3. revintage
    Joined: Nov 2016
    Posts: 344
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    Location: Sweden

    revintage Senior Member

    The tri build will be completed 2023, but I will false start this summer by building the widest catamaran of the available parts. The ladies in the family asks for sun decks, so by adding two removable 18x600x2200mm Paulownia boards this will be taken care of.

    Up to six boards can be used on the tri, when in sun bathing mode;).

    Did a detailed weight analysis and the tri will be a little heavier than expected, at just below 500lbs. To compensate for this I will use a bigger rig: Tornado mast, Inter 20 main and Tornado jib, 23,35 sqm.
     

    Attached Files:

    Last edited: Feb 15, 2022
  4. revintage
    Joined: Nov 2016
    Posts: 344
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    Location: Sweden

    revintage Senior Member

    I have given up on the Tornado hull I was given from the nice guy in southern Sweden. Did some calculations and it will not be economical to make the 1200km trip on my own to collect it, together with time loss and costs for modifying the hull.

    Realized I have no time for the catamaran project I was building around my 5.8 hulls(see image), will instead take one of the hulls and combine it with the 5.5 as amas. It will be kind of plug&play as the three have the same beam pockets for 100-102mm beams and the same distance between them, ie the beams will drop right in, without any hull modifications at all. The front beam will be 3.2m 100x3mm with 0.7m 90x3mm outer ends and the rear beam 2.8m 100x3 with 0.9m 90x3mm outer ends, to end up with a beam of 4.6m. I have just ordered 4m 90x3mm together with joining hardware from Germany to arrive next week.

    The 5.8 hull is slightly shorter than the Tornado. The amas are 20cm shorter at the stern, 10cm shorter at the bow and 10-15cm lower then the aka. I might need to add a spacer in the aka rear pocket, to make everything line up properly with the ama bows a little down.

    So from two old beachcats I get one tri and quite a lot of leftovers to sell.

    The sketch is adjusted for the 5.8 aka.

    68173411117__4F863BE9-840B-4A72-B87C-DCB5AC7FC000.jpeg trinetcat58.png
     
    Last edited: Aug 10, 2022
  5. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Senior Member

    Mock up of the boat in 8.5 ft trailer mode. Spacers needed under both beams to lift the akas ca 4" wrt the center hull. Unfortunately the center hull beam pockets are 3cm further apart than the amas. Not a problem though, as the rear beam anyway will be lifted above the pocket as the amas needs a little bow down. The sketch shows the final beam arrangement that allows trailering when "folded".

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    Last edited: Sep 1, 2022
  6. revintage
    Joined: Nov 2016
    Posts: 344
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    Location: Sweden

    revintage Senior Member

    Spacers to lift the amas and also create bow down. A little clumsy but made with standard material.
    It could be made otherwise but the idea is to keep the center hull intact, if wanting to reverse the build.

    rear beam spacer.png beam spacer.png
     

  7. revintage
    Joined: Nov 2016
    Posts: 344
    Likes: 63, Points: 28, Legacy Rep: 10
    Location: Sweden

    revintage Senior Member

    Rear beam ready at 17kg. 2.6m center part 100x3 with 22mm low Harken track. Outer tubes reinforced 90x3, 300mm overlap. Reworking the coupling with stainless clamp instead of 10mm bolt.

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