Small Tri's under 20', any mention of foils is banned..

Discussion in 'Multihulls' started by waynemarlow, Jan 13, 2015.

  1. Richard Woods
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    Richard Woods Woods Designs

    Strip planking is expensive these days, and is heavy for smaller boats. So foam is the sensible way to go

    As always I don't write enough detail, which confuses. I meant that the cost of a used beach cat is way less than new cost (USD1000 for a useable one in the UK, like a Hurricane 5.9). The outriggers and rig on these tris must be a similar cost to a new beach cat

    So, if you just bought a main hull for say USD8000 you could get a boat on the water for USD10,000 with only a little work

    That's a figure out of the air based on a hull with 30sqm foam and 100kgs glass/resin plus 75 hours labour for a moulded boat (three large mouldings). 24ft Strider Club catamarans took 200 hours from scratch to rigged and out the door. They were more than twice the work (two larger hulls plus cockpit tray, rudders and rigging)

    Thank you for the French Connection, I 'll contact them

    Richard Woods
     
  2. rcnesneg
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    rcnesneg Senior Member

    The Tornado is a plywood construction boat. Look how that turned out, extremely fast catamaran, good looking hull shapes too.
     
  3. Richard Woods
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    Richard Woods Woods Designs

    It cannot be fast can it? I mean it has flat decks, not rounded, a raked bow, not a ram bow and it's made of wood - come on! It doesn't even have un-mentionables

    I am getting old. If I can spend 150 hours building a flat panel plywood hull I can be sailing this summer. If I build a foam sandwich hull it might take 500 hours, so I won't be sailing until 2018. And I bet I wouldn't notice the difference on the water

    4mm ply is pretty light, hard to beat with regular foam sandwich, and a hard chine hull generally has a narrower BWL than a round bilge one

    What do you think of this boat?

    http://www.wally.com/wally-118/

    count the curves

    Richard Woods
     
  4. davefried
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    davefried Junior Member

    This is my idea for a small sailing trimaran. I have been following this thread hoping to learn a little more about trimaran design, maybe enough to try building this boat.



    SOR

    Day sailer in sheltered or costal waters.

    On water folding for narrow berth or trailer.

    Home build hull and outriggers, flat panel plywood or foam.

    As fast as it will go with a modest rig and no foils.



    Waterline length 6.0 m

    AMA center to center spacing 4.5 m

    Hull l/b 10.0

    Payload 300.0 kg

    Displacement 600.0 kg

    SA/D 30.0

    Main + Jib 21.0 m^2



    By the numbers it looks like a Woods Strike 20 with the F18 rig. I may well go that route, but for now, this is what I have been toying with.

    Dave
     

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  5. tamas
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    tamas Junior Member

    Davefried, you seem to be on the money with your spec's. My comments for what it is worth being a bit of a newbie to tri's.
    Lets not compare what this tread is about (new class of tri) and catamarans, what is the point.
    A cabin or not, that is a personal choice and does not matter either. Make it optional.
    No foi - oops cant mention them.
    Something similar to Pulse 600 or TC627 would be a good start, they both look like good designs.
    The use of existing cat hulls for amas and home build in ply or foam acceptable.
    Number of crew optional but 2 as a minimum.
    My Husky cost was about $9,000 with donor boat costing $3,000. I used everything including rig, trailer & sails (I bought a second hand spinnaker). No labour costs except for the folding system build. Those are actual cost to give you an idea of what direction to take a T20. EG: is it worth getting a donor cat against starting from scratch. The only reason I chose to build a Husky was the cost of an off the shelf tri of about this size was out of my range and there is nothing similar that I could afford (under $10,000) available second hand. Cheers
     
  6. rcnesneg
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    rcnesneg Senior Member

    How are you guys planning to prevent leeway? single daggerboard? Centerboard?
     
  7. basil
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    basil Senior Member

    I certainly am enjoying reading this thread particularly due to the setting of the exclusion of the "F" word. Way less dogmatic than usual.

    I've just priced out a Duo660 catamaran and though only demountable (several hours assemble/disassemble) it comes out at aruond $30000 in materials alone. So the appeal of what Richard Woods has available sure has considerable merit.

    His tri's have a good amount of appeal due to simple construction and donor huls and rigs. I do wonder about flat panel boats tending to be boxy to some eyes and not too trendy looking, but if you want cheapish building plywood is it.

    Nobody here has mentioned Mike Waters W17 tri, while not using donor boats it looks fast and looks good.

    I believe the 20 foot trimaran has a place in the market if it is appealing to look at is modestly priced and if you have the time and expertise it should be simple to put together at home.

    Richards thoughts about building a main hull and having home builders finish it at home sounds good but unless there is a worldwide dealership organised I can't see it working.
     
  8. RHP
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    RHP Senior Member

    Richard's idea caught my eye immediately and could in principle lead to improved sales as technophobes like myself gain the confidence to give it a go.
     
  9. waynemarlow
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    waynemarlow Senior Member

    Basil sort of sums up where I've got to in my thinking, that yes a 20ft folding Tri is probably where I'll end up fairly soon in my sailing career. Would I fork out £30K for that boat, no. Would I put £15K into that boat, probably yes. That leaves building a boat or having a boat built the only real option then.

    Would I build a flat panelled design, no, they are just " fugly " to say the least. What I want is nice rounded modern lines such as the Pulse and Searail, I guess that means foam sandwich construction, yes that will mean 500 hours construction rather than 200 hours, but I will have a much better looking boat and thus a much more saleable boat when I come to move up to the F85SR I have planned to own. Sorry but to own such a boat, to me it has to not only sail well, it has to look good as well.
     
  10. rapscallion
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    rapscallion Senior Member




    exactly!
    I'm working on a trinado design myself, similar to the wally in astethics, but more of a poly design, like this:

    [​IMG]

    It will be designed around the tornado, but I'm going to use the most powerful beachcat I can find. The deck house won't be that complicated, but it will be inspired by poly design.

    I also plan on using the L7 sliding beam system, as the beams used for that design are an off the shelf product.

    Hulls made from 1/4 ply, and decks made as follows (from the multimarine website)

    "If you are going to use it as a "deck" or sitting/walking surface, then point loading problems can be solved by bonding 1/8" plywood to the top surface. A typical layup would be (from top to bottom) 3 oz. glass, 1/8" pl;ywood, 1/2" to 1" styrene foam, and then 10 to 18 oz. glass on the bottom. We sand bag or vacuum the plywood to the foam and do hand lay-up for the glassing. It will be light, stiff, inexpensive and strong."

    I'll use less than 10 oz for the deck house as the corners will give the structure strength.

    I'm aiming for an all up weight of less than 900 lbs.
    No sea stays, low freeboard, 17'6'' beam and a 20' length.


    The goal is to be faster than a pulse 600, and capping the budget to be less than a new set of sails for the pulse 600, perhaps 5k to 6k US.
     
  11. davefried
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    davefried Junior Member

    Accommodation

    I chose to go without a cabin leaving 2.4 m between the beams to move around in comfort. It is a small boat, at 192 cm I would find an enclosure rather tight.

    I have considered covering the first metre or so of the space between the beams to allow for a sheltered portapotty. I would need 1.4 m clearance above the sole so the enclosure would only add .3 m to the height of the hull.

    A boom tent or something like it could make an overnight possible. Folding the outriggers would stabilize the boat and avoid rocking from side to side as the outriggers are clear of the water at full load when extended.
     
  12. Doug Lord
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    Doug Lord Flight Ready

    F***

    ======================
    I think maybe you forgot to tell these guys something you posted on the other 20' and under thread?

     
  13. hump101
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    hump101 Senior Member

  14. waynemarlow
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    waynemarlow Senior Member

    Doug put yourself on the naughty step, can I ban you from this thread for a week as you have used that naughty word :), and who said my next boat that I build will be a 20 footer, I need a lake speedster, plans a foot for a very special 14 footer with yes can I say it, no I can't in this thread.
     

  15. Doug Lord
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    Doug Lord Flight Ready

    F***

    ==================
    The essence of hypocrisy?!
     
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