Small trimarans under 20'

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

  1. Tiny Turnip
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    Tiny Turnip Senior Member

    My 16 ft cruising tri is pretty dry (high freeboard, with its roots in an outrigger sailing canoe) and with a modest 80sq ft ketch will reach about 12 knots before I start breaking stuff.
     
  2. upchurchmr
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    upchurchmr Senior Member

    Tiny,

    Don't think I remember your boat - can you post pictures?
     
  3. Tiny Turnip
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    Tiny Turnip Senior Member

    Of course, Upchurchmr.



    the video features my boat, her sister (they were built together initially for the partners of Solway Dory) and one of SDs smaller single masted sailing canoes- a Fulmar I think.

    rigs are unstayed, so reefing by rolling the masts. On more recent boats they have replaced the beam lashings with a clever system using an aluminium spar and keyways, which allows the main hull and amas to be assembled very quickly. it also means you can slide the dockside ama next to the main hull to allow easy disembarking at the dock. I'll see if I can find a picture of this.

    designed for 2 people plus ample camping gear for beach hopping around the west coast and islands of Scotland. rigged empty weight about 100 kg.

    N.B. This is a bigger boat than the Osprey, featured on the SD website - something of a special edition.

    Not a racing machine, obviously, but I find it difficult not to push her hard because it is so easy to sail and so much fun. Should be very difficult to tip over.
     
    Last edited: Jan 12, 2016
  4. Tiny Turnip
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    Tiny Turnip Senior Member

    1 person likes this.
  5. upchurchmr
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    upchurchmr Senior Member

    Thanks,

    I had seen them before but didn't realize one was yours.
    Any comments on what you like or would do different?
     
  6. Doug Lord
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    Doug Lord Flight Ready

    ================
    Thanks, Tiny ,for the pictures particularly that neat crossarm mount. The boats look great and seems like they'd be a lot of fun for a mini cruise.
     
  7. Tiny Turnip
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    Tiny Turnip Senior Member

    Well, I have always liked canoe sterns aesthetically, and the sliding keyway system works very well I believe, so I would like both of these features, even at the loss of a little accommodation volume.

    The minor damage the boat has suffered has been slightly popping the hull ply around the leeboard pivot, and cracking to the rudder stock, both occurring I think when I have been having fun pushing the boat hard.

    I have strengthened the leeboard pivot reinforcement now, and am considering best way forward with the rudder stock. The foils are beautiful and powerful; the rig is the largest that has been used on any of the SD boats, and I suspect that the incremental evolution of the boat from its sailing canoe roots, coupled with my enthusiasm for speed jollies, in a boat designed for cruising, has found the limit of these details.

    I have wondered about nets between the hull and outriggers, but they're really not necessary, and would encumber paddling in light winds.

    I have considered a tiny cabin, just a berth really, but it would need a tent too, and to my mind, sleeping in a small boat at anchor and feeling comfortable and secure needs a very sheltered spot; A boom tent would be needed as well in wet weather, and the boat weight would increase. At around 100kg rigged it is on the limit for carrying up a beach,( though it can transport its own dolly.) On balance, being able to get the boat above high water mark on a beach easily, and pitch a small tent and maybe a cooking shelter is much more practical. Its easy to get sucked in by Swallows and Amazons images of sleeping in a tiny cabin. :)

    And there was a time, egged on by my sailing buddy, and a bottle of Islay malt, when we sketched a catamaran version with a biplane ketch rig, cabins and pedal drives... :D
     
  8. Tiny Turnip
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    Tiny Turnip Senior Member

    Thanks for the kind words, Doug; I have to say I am pretty happy with the boat, and when I think about 'My Ideal Boat', I mostly come back to the one I have.

    (Unless I can find one lighter, faster, and cheaper, with a tiny cabin :D)
     
  9. upchurchmr
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    upchurchmr Senior Member

    Sounds like a nice boat that just needs the normal "development" to extend the limits of how you sail.

    Have you gotten close to running the ama bow underwater when reaching?
     
  10. Tiny Turnip
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    Tiny Turnip Senior Member

    Yeah, I ease off when the beam starts hitting the water - seems to me that its unlikely to go any faster at that point if we're pushing the boom through the water, plus the lashings aren't really designed to take force in that direction.

    There's 200kg of buoyancy in each ama - the stresses must be getting pretty high all round for a lo-tech boat with unstayed rig. With hindsight, I can quite understand why the leeboard foil could pop out a blister of 6mm ply -it would exert a twist on the ply panel locally. I've since extended the reinforcing panel in width, and taken reinforcing ribs (partial bulkheads) down to the bottom panel.

    It also has a brace across the boat at the level of the gunwhales.

    I know the folk that bought the sister boat a little. They're pretty hardcore, and they claim to have hit 15 knots. That's hard for me to believe, tbh, but I'm relatively cautious.
     
  11. upchurchmr
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    upchurchmr Senior Member

    Last question - what's the total boat weight with the equipment you normally carry?
     
  12. Tiny Turnip
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    Tiny Turnip Senior Member

    That's a tough one, Upchurch - the boat is so relatively capacious that I've never felt the slightest need to limit camping gear. Lets see...

    rigged empty boat: 100kg

    2 adults - 160 kg

    have sailed a number of times with + 2 children - say 80-90 kg for both

    camping gear (without additional children) is normally backpacking tents, primus and jetboils, - backpacking level stuff, say 20kg plus 10kg water, plus 5kg supplies, but I'm considering trying our full 'out the back of the van' camping kit, because its so comfortable, which would include 25kg of canvas bell tent , 15kg of woodburning stove, flue, 10 kg of cookbox and related items... Sorry I can't be more accurate, but the 2 children is probablymore weight than the camping gear, and the only constraint there is them very slightly constricting movement, not freeboard.
     
  13. tour
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    tour Junior Member

    Hi there thank you for the interest and some details.
    Long story short.
    Got a vaka from an boatbuilder/engineer for free, he had designed the hull to match Hobie 18 for rig and amas 12 years ago. So i bought the hobie and we built the tri. So this summer holiday we used it and fine tuned this prototype. Obviously a prototype and not a production ready boat. Our conditions where we use her is 10 - 35 knots of wind. Did a downwind solo blast in 45 knots of wind. Short chop up to 1 meter +. Area is Langebaan lagoon on the West coast of SA.
    Length 5,8 meters
    Width 4,4 m
    weight 320 kg
    Glassfibre with aliminium tube akas and spectra water stays.

    Boatspeed 15 - 22 knots.
    Issues - she is very wet. We will fix this in the next one.
    whats right - super stable, very forgiving, very quick, easy to sail, points very well,
    moves very well in very light winds.

    a few points.
    A lot of info says that the amas must just touch or almost seesaw from side to side when unlayden. On the prototype the amas are in the water. This makes her very stable when camping and also when the wind picks up. And in light wind she still moves well. More wetted area but more stable in a blow.
    Unfortunately we have no other boats to test her against but what a joy to sail. Trimarans are not big here so all info is via this and 3 other sites. So as soon as i get pics loaded i ll appreciate all feedback given.
    thanks
     
  14. CT249
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    CT249 Senior Member

    The fastest one I sailed was about 18' and would have arguably have been significantly faster than a 49er upwind much of the time; perhaps as quick as a Formula 16 cat that was not using its spinnaker in light winds. I'm going off very old memories, though.

    It was an Australian design (Bethwaite HSP) and never went into full production.
     

  15. tour
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    tour Junior Member

    Here some pics. Fire away
     

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