New Take on Tremolino

Discussion in 'Multihulls' started by Chris Ostlind, Apr 27, 2007.

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  1. Zoro
    Joined: Jan 2006
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    Zoro Size doesn't count!

    Rapscallion,

    To me it actually looks like a very good shape to cylinder mould and you would have to suppose that it would come out slightly lighter than 'stitch and tape' but I would not expect by much at all. That's a total guess though as I have only read about cylinder moulding and as you know it does have its shape limitations.

    Chris cheers, LOL.
     
  2. zigzag
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    zigzag Junior Member

    Donor amas

    I am a few years late for this but can hobie 17' hulls be used instead of nacrs
     
  3. TTS
    Joined: Jul 2007
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    TTS Senior Member

    An older Tornado rig would also work well with this design. It would be more powerful than the H-20 rig. I would like to a similar concept but with Tornado hulls as the amas. I think though the main hull would have to be larger though. The other issue is the buoyancy of the Tornado hulls.
     
  4. Eralnd44
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    Eralnd44 Wanderer

    Might be that a nice universal platform could be devised that would acceppt the hulls from several of the better beach cats. I'm not sure but do most cats have fore and aft tube distances that are very cloes to the same?
     
  5. TTS
    Joined: Jul 2007
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    TTS Senior Member

    The attachment points or beam boxes are similar to each other between different cats in the fore and aft measurements. None are identical, but very close to each other. There are many other differences that need to be looked at though, weight, length, buoyancy, stiffness, etc... So while a base can be established each hull will give you different properties.
     
  6. zigzag
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    zigzag Junior Member

    Seems that the tremolino is getting upgraded to larger displacement hulls. This implies that perhaps, as other current tri designs are lengthening amas as well the Hobie 17 hulls would be fine on an 18 to 20 foot aka.?? Chris White has a simple design, Discovery 20 (1968) that he claims outperforms the tremolino. His comments however about submersing amas is from what I can see a bit outdated. Re an aka that can be adapted to various donor amas a sliding
    adjustable / or multi embedded fixing point would solve the problem. How about the CE centerboard / mast location, Any Ideas ? I have access to very cheap hobie 17's in need of repair. Who is willing to chip in for a designer to draw something up on a group basis ? I think the trem is ok but a little more room would be nice, particularly for a 20 plus foot long aka.
    RE fixing 6T alloy tubes, on my current mini tri I use plastic scaffold swivel clamps ( disassembled into two pieces and bolted down to the top of the amas)
    Is the Hobie 17 sail too underpowered for a 18'- 19' tri. I have a technique posted on the forum of using Polystyrene strip plank. (now upgraded)
    Each 12mm x 50mm plank is glued down with a running strip of epoxy coated
    woven roving tape. The tape must be long enough to drape down on the inside after embedding in the join to a distance just under the outside hull surface ( to allow for fairing.) The tape will lap down over the previous inner plank to provide a first bond of the internal side, when finished follow up with unistrand plus light woven matt vertically. Remove from mould, and fair off the outside. Open up the seams a little with a knife to expose the glass between the strips, or provide aris before hand. Mix a lightweight filled epoxy and squeege into the grooves. Then use squeege to level off the surface and when tacky lay up some vertical unistrand on the outside,
    All the styrene planks have been fuly encapsulated and there are horizontal stiffening webs to stop any delaminating.
    One problem of epoxy getting on the outside of the hull may be solved by dunking then using a roller to drain out excess resin and using a peanut butter consistency epoxy from a cake icing bag. Foam does not require a lot of strength / bond what is required is the embedded tape stiffner. Why insuation foam ? the strips cost about $7.00 per 50 metres length,(use hotwire to keep wastage down)my first guess that provides 2.5 m2
     
  7. cleblanc
    Joined: Dec 2004
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    cleblanc Junior Member

    Interesting design

    I have this unused Nacra 5,2 sitting on a friend's lawn, this looks like an interesting design that could give a second life to this boat.

    However, the Nacra 5,2 hulls are very thin and I am not convinced that they would be durable enough for this purpose. I used to have a Nacra 5.7 and the hulls had much thicker walls.

    Charles Leblanc
     
  8. primozk
    Joined: Aug 2007
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    primozk New Member

    I have a Dart 20 today and thinking to convert it into a tri.
    Laguna is an interesting design. I see the most similarity with Tricat 22. so I'm comparing it with it.

    Chris, I have some questions -
    - what do you think about using Dart 20 amas and rigging (LOA=5,94m, Mast=9m, SA=main 18m2+jib 5m2)?
    - how wide is the main hull, would there be place for one/two berths?
    - when the plans would be available
    - do you have an opinion how long would it take to build the boat?
    - where could be an outboard mounted (have a Honda 2.3 HP)?

    Potential other solutions I'm considering regarding converting D20 in with some more place to sail with the family
    - Z65 (waiting for news...)
    - Predator 21 (any oppinions about this boat?)

    Regards, Primoz
     
  9. Pzary3233
    Joined: Sep 2007
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    Pzary3233 New Member

    Chris,
    Sorry to bring the thread back from the dead...

    I too have access to a Nacra 5.2 and I was wondering if/when it would be possible to purchase a set of plans. To me this seems like a very fun little boat! What would you think about cedar strip construction?

    Up forward, is there room for say a single person with a sleeping pad?

    Thanks!
    Paul
     
  10. ThomD
    Joined: Mar 2009
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    ThomD Senior Member

    My feeling about donor amas is that it takes about 20 hours each to make an ama to the point where you start to bring it together with the hull, using the fastest techniques like stressform, so it really makes no sense to compromise hundreds of hours of other work to get the amas you don't want for the project. Of course there may be amas out there so tasty and cheap that they recommend themselves, but I think that would be a rarity.

    A center cockpit is smart on a boat this size, it's great to project the layout of the larger boats on smaller ones, but often if you run real numbers these boats have a carrying capacity of only a few hundred pounds, and are overweight on the drawing board. Newick has designed a slew of these center cockpit boats from the world beating original Val, to the Tremolino, Horizon, B2. They tend to be misunderstood, but are actually pretty clever designs.

    These weight problems are all the more likely if something like CM or Stressform is attempted in the main hull since while that guarantees light hulls (in the latter case anyway), it also means pretty narrow ones. One really wants to save weight everywhere possible which might argue for no folding connectives.

    One has to be careful on the theory around something like a CM process, on small boats, technically superior processes may end up heavier just because of materials break points. Like you can get more sizes of materials like strips and ply than you can CM panels (smallest is generally two 3mm plies), or even core materials that tend to go 6mm 9 mm etc... 9mm foam may be really light but it's 50% thicker than 6 so it may, or not, require milling or other consideration.

    One thing that is possibly overlooked about the Tremolino, which has gone down in history as a boat with amas that are too small, and a rig that is underpowered, is that it is really a pretty fair 20 footer. I know of a number of boats out there that have carrying capacities of as little as 250 pounds in these small sizes. What that really calls for is a boat with the hobbie size rig and floats, and an oversize main hull. From a jock perspective that's a 24 footer without any guts, but from a design perspective, it's a small cruising tri with a real displacement figure. Displacement increases with the cube of length, so some proportional changes in configuration or simplification of main hull appointments, as here, are wise.

    Local rules will vary, but I would be really skeptical about jamming this boat on a beach cat trailer, at least for something other than a very local hop. I like the idea of small trailerable craft with removable main hull sections so you can toss something not much larger than a traffic cone in your tow vehicle, yet add 3' or more WLL to a smaller towable rig. With these small borrowed sail rigs the forestay doesn't always make the bow anyway. I don't know how many municipalities have similar rules, but we have a 20' rule for stuff one leaves in the driveway. Never really sure whether that includes the tongue of the trailer or not. When it comes to explaining yourself, though, smaller is always better.

    (on the larger scale tris, I had a conversation with John Marples, whose trailer design I had built, about where trailerability stood today. There are a lot of new state regs, and he pretty much felt the circumstances had really changed almost to the point of it not being worthwhile. Of course his boats are a lot larger on a trailer, and push the limits a bit more. Small trailerable rigs are all over the place. Just to say it needs some serious investigation the more developed your state laws are.)
     
  11. DennisRB
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    DennisRB Senior Member

    Has anyone built anything like this yet?
     
  12. redreuben
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    redreuben redreuben

    i would question the use of flat crossbeams on a boat this small, they will be very wet and the drag on wet tramps is horrendous. I would use gull wing beams as in the doubloon picture on duckworks albeit more expensive to build.
     
  13. Richard Woods
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    Richard Woods Woods Designs

    Have a look at my Latest News page for details of my Strike 18.

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  14. bill broome
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    bill broome Senior Member

    this is a pretty boat, and a 6m folding tri is a good market to draw for.

    i would pin a dagger board to one side of the boat with a simple bar frame. easier to make, and if you don't like the balance, easy to fix.

    i thought farrier built this sort of articulated aya first, in his trailertri. great idea, whoever did it.
     

  15. Richard Woods
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    Richard Woods Woods Designs

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