Trailerable Trimarans

Discussion in 'Multihulls' started by Thomas Rheuble, Apr 21, 2003.

  1. Hello: I am new to this site, but am impressed with what I am seeing here. I sail a WindRider17 in the Gulf of Mexico, and am looking to step up in size. The logical choice would be a Corsair or a Dragonfly. Is there anyone out there with experience with one? Thank You Thomas Rheuble Rheuble@aol.com
     
  2. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    I am a part-owner of a Corsair F-24 MkI, and I've sailed on an F-27 and F-9's. I highly recommend the Farrier designed trimarans. They are great boats and you can get some terrific deals right now.
     
  3. tspeer
    Joined: Feb 2002
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    Likes: 170, Points: 63, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

  4. tspeer
    Joined: Feb 2002
    Posts: 2,201
    Likes: 170, Points: 63, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Here's a post from a new F-27 trimaran owner to the Mulithulls mailing list (note: pretty much all the F-boats have a roller furling/reefing boom, and some have slab reefing installed in addition):

     
  5. Guest

    Guest Guest

    Flat bottomed planing hull on a tri??

    I have a really strange idea that I would love to get your opinions on.
    Almost all of the trailerable trimarans I’ve seen use a very narrow deep v shaped main hull. I assume that this design has evolved to minimize wetted area and to minimize leeway and to help windward performance. This design gives them good performance but it only leaves a very narrow hull for accommodations. And in the length that is reasonable for trailering (up to 26 feet) there just isn’t enough internal volume for comfortable accommodations. Has anybody experimented with a flat bottomed trimaran? It seems to me like a hard chined flat bottomed hull would hop up on a plane very quickly. It would be like lightning downwind and lee boards could be used to improve windward performance. If the main hull had an 8 foot beam (for legal trailering), This would give huge inside volume for accommodations. Sure it would pound over waves, and it would never be a blue water circumnavigator, but if it was built solidly it should do well in protected waters?? I know that Seapearl has a trimaran version of their 21 footer. I’d be really interested to know why no one else has tried this. I’m hoping to build a prototype soon, but first I’d really like to get opinions on why a flat bottom (with leeboards) wouldn’t work on a trimaran.
     
  6. yipster
    Joined: Oct 2002
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    Location: netherlands

    yipster designer

    hello guest,
    i recognise the thinking, i had the same. apart from hard chined flat, an 8 foot beam gets you into single hull wave resistance and hullspeed limits. offcourse when you can get it to plain...

    yipster
     
  7. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    The V shaped hulls went out with the Pivers in the first generation of offshore multihulls in the 1960's! Today's multihulls either have rounded sections for minimum wetted area or flattened sections for more space and planing.

    The Farrier designs definitely have planing sections with rounded bilges, and there's a definite difference offwind when the main hull starts planing - the boat just keeps going faster and faster.

    This drawing shows the non-V shape of a Farrier design: [​IMG]

    My experience with the F-9 (31' version) is that the flattish forefoot does pound a little bit when going upwind in a sizeable chop. I prefer the lines blended from, say around 30% Lwl to a more rounded shape at around 15% Lwl. That would preserve the planing run and cabin floorspace while easing the entry when the bow moves vertically down onto a wave.
     
  8. Doug Lord

    Doug Lord Guest

    Planning tri

    I built a high powered planning hull tri in 1974 that would plane upwind and go like a bat out of hell off wind. The main hull was 20' LOA and about three feet wide; she weighed about 350lb all up.
    She would plane upwind in about 8mph true.
    Downside: she was slow in light air.
    As a compromise for achieving interior room I think it is viable but you'd get a better ride in nasty stuff in a Farrier or similar design.
     
  9. Stephen Ditmore
    Joined: Jun 2001
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    Location: Smithtown, New York, USA

    Stephen Ditmore Senior Member

    My understanding is that the wavemaking drag goes way up if the length to beam ratio goes below 10:1.
     
  10. Guest

    Guest Guest

    Beam to length

    I guess it pretty much depends on whether the hull is a planning hull or not; most skiffs have beam to lengths below that and of course many multis are much higher. Bethwaite talks about the "humpless" hull that transitions more or less smoothly from displacement to planning speeds-at beam to length ratio's below 10/1....
     

  11. Catri


    Also do consider the Catri boats, I am very happy with that choice !
     
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