Small trimarans under 20'

Discussion in 'Multihulls' started by Doug Lord, Jun 24, 2012.

  1. Doug Lord
    Joined: May 2009
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    Location: Cocoa Beach, Florida

    Doug Lord Flight Ready

    ===========================
    Eric Sponberg quoting Dick Newick:
    Dick Newick is one of this country's foremost multihull designers, with specialty in trimaran design. He's mostly retired now and living in California, but I thought his opinion, printed in the March 1988 issue of SAILING WORLD, is worthwhile and to the point: I quote:

    "I've predicted all along that a good trimaran will beat a good catamaran almost every time. For an all-around multihull racer-cruiser, I would suggest that tris have the following advantages: They have more stability because they are wider for a given length. They have more maneuverability because when they turn, they are dragging two long slender hulls cross-ways around an imaginary point in the middle--they have one long slender hull pivoting around the same point with the amas largely out of the water. They have an easier motion at sea; they don't have a quick jerky motion; they don't pitch anywehre near as much going to windward. With a smaller-size cruising boat you can get more useful accommodation without excessive freeboard since it's down in the hull instead of on a platform several feet above the water. And, because of the trimaran's easier motion, it is much easier on its, rig, so it doesn't need a heavy one. Lastly, you are stepping your mast in a hull, instead of someplace out over the blue water, and therefore your engineering problems are fewer.

    "In really light weather the trimaran has a very big advantage in less wetted surface. When you can't fly a hull in a catamaran, you're just stuck in the water. As soon as you're sailing practically, you're flying the weather hull on a trimaran. Other than that I think catamarans are fine."


    Eric
     
  2. Cholsson
    Joined: Aug 2015
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    Cholsson Junior Member

    Did some more sailing yesterday. But was not able to break 20, It will come I hope.
    Tweaked and corrected different things like rake, sheet.
    Next step is to... Sail! and learn to handle the boat, not only in pitch-perfect-sidewind :)
     
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  3. Doug Lord
    Joined: May 2009
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    Location: Cocoa Beach, Florida

    Doug Lord Flight Ready

    Cholsson, your boat is, technically, an excellent candidate for the application of lifting foils-have you given that any consideration?? You would certainly break 25+!
    The boat-the video-sure looks good-have fun!
     
  4. Richard Woods
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    Richard Woods Woods Designs

    Of course there is no point having a boat that only sails fast offwind. Unless it can sail well to windward eventually you get trapped on a lee shore. So here is another Strike 20 video showing Patrick's home built plywood boat sailing to windward at 10+knots. Still with the 76yr old helming, still with the 60+ crew



    More on the Strike 20 here

    Sailing Catamarans - Strike 20 racing trimaran using a F18 beach cat for hulls and rig http://sailingcatamarans.com/index.php/designs-2/27-trimarans-under-25/433-strike-20

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  5. patzefran
    Joined: Feb 2011
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    Location: france

    patzefran patzefran

    I Richard,
    In fact the crew (myself) is also 70+ (72 in July) !


    Cholsson ,
    Congratulation for your nice build, I know what I mean, having built eight multihulls (wooden !) from 32 feet to 15 feet.
    Your boat seems very light ( ?) which is a key for good downwind performance, apparently not far from a classic A cat downwind.
    My Strike 20 could be faster downwind, but it use very heavy Nacra 5.8 hulls (62 kg each !), and also a very heavy Hobie 21 mast (I had a nice 11 m carbon mast on my former Tremolino
    weighing only 14 kg !). Nevertheless it is a very powerful boat, having very good mean velocities upwind and downwind, and able to carry 4 crews in confort.
    Are your beams carbon ones ? It seems you have no water stays in the new configuration ? I wait to see you lifting the mainhull upwind.
    Best wishes
    Patrick
     
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  6. Cholsson
    Joined: Aug 2015
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    Cholsson Junior Member

    [​IMG]

    Compare to how it looked like 2016..
    [​IMG]

    Thanks patzefran! Your boat seems really cool. I planned to sail the boat alone or with a light girl.
    From last year I have, removed the waterstay. I change the beam in front from 50 mm alu, to 90 mm carbon pipe
    (Same carbon pipe the M32 cat uses as bowspirit)
    I also rebuilt a lots of other things, built a "keyboard" for all sheets be reachable slightly in front of you with correct angle to
    tighten and release sheets and more. It worked out well. I hate to have my main-sheet behind me. But thats probably just personal opinion.
    I saw new trampoline my self and other thing. A new self-tack-track as well.
    Anyway, it feels good,, and I think it has great potential. I have a gennaker I will add during summer.
    But... I really need to sail it now and learn how it behave :)
     
    Last edited: May 13, 2018
  7. Richard Woods
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    Richard Woods Woods Designs

    Looks much better now, a much stiffer platform.

    maybe its the camera angle, but can you get enough jib leech tension? the track seems a long way aft

    Richard Woods
     
  8. Cholsson
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    Cholsson Junior Member

    Yes its super siff now. The jib leech was ok. I can move it back if i need. Fore stay is on a track. Only problem was main sheet. I did not have the power to tighten it.
     
  9. upchurchmr
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    upchurchmr Senior Member

    Now all we need is cubic $$$$ to pay for the technology. (talking about the foils).

    Cholsson, the boat looks much better.
     
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  10. patzefran
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    Location: france

    patzefran patzefran

    Your boat looks really good now ! Are your 90 mm OD bams in two parts or single ? It seems you need a circular track aft for sheeting the main sail all round. Generally, the mast step is on the main beam on cats (on my Strike 15 as well), with your configuration I assume you made adequate reinforcement inside mainhull to take the mast compression loads. Beams attachment on hulls needed also good carbon engineering, nice job !
     
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  11. patzefran
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    Location: france

    patzefran patzefran

    Sorry, beams, not bams !
     
  12. Cholsson
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    Cholsson Junior Member

    Both beams are one part (4 meters each).. I have reinforced the boat inside as well, but difficult to know if it was too little or too much. For main sail sheet, I will think about how to improve it. Its no panic at least :)
     
  13. redreuben
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    redreuben redreuben

    Reinforcement; racers rule is........
    If it breaks its to light.
    If it doesn’t break its too heavy.
     
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  14. upchurchmr
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    upchurchmr Senior Member

    Carbon is the magic cure?
    Lots of boats sail just fine without carbon.
    The point to carbon is that if you don't want to waste your money, you need to be able to do real enginering design to make it cost and weight efficient.

    How much does the "new" boat weight?
    Are you able to drive the ama underwater with sail power? Can you fly the main hull?
     

  15. Cholsson
    Joined: Aug 2015
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    Cholsson Junior Member

    Dont think Carbon is magic, but I change 50 mm alu pipe to 90 mm carbon, that I got hold of.
    Weight is pretty much exactly the same as before, but it does not flex like crazy as it did before.
    Boat feels much better now anyway :)
     
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