18' Trimaran vs F18 Catamaran

Discussion in 'Multihulls' started by Doug Lord, Jun 13, 2010.

  1. Doug Lord
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    Doug Lord Flight Ready

    Does anyone know of an 18' trimaran design that has beaten or that has the numbers to possibly beat an F18 cat around a course?

    F18 Capricorn cat developed by Martin Fischer:

    Length 5.52 m / 18.1'
    Beam 2.60 m / 8.5'
    Mast 9.08 m / 29.78'
    Total Weight 180.00 kg / 396 lb.
    Sails: Mainsail 17.00 m2 / 182.9 sq. ft.
    Jib 3.45 / 4.15 m2 / 44.65 sq. ft.
    Upwind total: 227sq.ft.(big jib)
    Spinnaker 19.00 / 21.00 m2 / 225.9 sq.ft.
    Price € 18.000,=
    Only beach cat I know of with gybing daggerboards!


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    Last edited: Jun 18, 2010
  2. dstgean
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    dstgean Senior Member


    I don't know of one--but I would have a hard time thinking it would be easy under a certain length. the A - D cats are open development and there aren't any serious contenders other than cats at this time.

  3. Doug Lord
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    Doug Lord Flight Ready

    The C Class tri Victor T was apparently quite fast-winning the North American
    Multihull Championship in 1969. 25'LOA, 18' beam, 300 sq.ft.,300 lb.. But, like you say: "at this time" I've been unable to find any 18' tri-built or completed design-that could beat an F18. I sure believe it could be done-and will be surprised if nothing at all turns up in this thread.....
  4. ThomD
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    ThomD Senior Member

    One thing that is a little too bad is that the Gougeons built quite a few boats many of which have never been that well documented. At one point I had some multihull digest type book, and there was a very small Gougeon articulated tri in it. It appeared to be a smaller version of Victor T, though maybe it was just perspective.
  5. Chris Ostlind

    Chris Ostlind Previous Member

    So, the looming question is... Who cares?

    Really, who cares if an 18' tri can beat an F18 around some set of cans on the water's surface? Let's just say that it bothers somebody so much that they do draw and build a boat for the task... Then what?

    Does it mean that F18 sales will drop like a rock? Does it mean that multihull folks will all rush out and throw big money at the product and some worldwide fleet will appear over night?
  6. Doug Lord
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    Doug Lord Flight Ready

    I care as would many other people. People who were impressed by Martin Fischers work on the development of the Capricorn F18 and his new boat. People who care about the new foil technology on the NACRA 20. Anybody that cares about the development of small multihull technology. People who like speed with comfort. People who liked the raised seats on the Hobie 17 and 18. People who were impressed with BMW-O USA! People who would value a boat that could be sailed with maximum sail area singlehanded or with a friend or two-with the same margin of safety and Righting Moment in either case.
    Since this design hasn't been done yet who knows what the technological advances incorporated in an 18' tri could lead to?
    Looking at the potential offers all kinds of approaches like a boat faster than an F18 that allows the crew to sit comfortably on the side of a center cockpit-no hiking, no trapezes ,no running back and forth. A boat whose chance of capsize or pitchpole would be an order of magnitude less than an F18 for the same or greater speed. A speed boat with advantages not found on any beachcat!
    It's not too hard to visualize a boat like this revolutionizing the small multihull market: intense speed(faster than the fastest F18), intense comfort, ease of handling and transport, a boat like no other on the market.
    I'd say there are a bunch of good reasons for a state of the art 18' tri....
  7. Chris Ostlind

    Chris Ostlind Previous Member

    And I would suggest that you don't have a clue about that of which you speak. I'll leave the debunking to others, Doug, but your summary is so full of holes that it makes my eyes hurt to read it.
  8. Doug Lord
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    Doug Lord Flight Ready

    Aw gee Chris-go ahead-give it a try! I bet you don't even understand what I wrote-------
  9. Chris Ostlind

    Chris Ostlind Previous Member

    Yep, that's it, Doug. I simply do not understand it.
  10. Doug Lord
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    Doug Lord Flight Ready

    Thats ok, Chris-I know....
  11. Doug Halsey
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    Doug Halsey Senior Member

    Hey Chris,

    I, for one, am interested in the tri vs. cat question, both for small round-the-buoys racers & for large round-the-world records.

    If you don't find any particular thread interesting, feel free to ignore it. Please stop subjecting all of us to your petty, juvenile rants.

    Doug Halsey
  12. Doug Lord
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    Doug Lord Flight Ready

    F18 vs 18' tri

    There are a number of considerations in a possible F18 killer tri. This is just one angle to look at:

    1) the tri would have between 14' and 18' of beam.
    2) the tri would be designed to fly the main hull from a 5 knot wind
    3) the tri could be designed to have the same or much more SA than the cat
    4) the tri would be designed to achieve maximum RM either single handed or with two people aboard
    5) the tri could be designed to have crew seating near the center of the boat virtually regardless of SA(within reason)
    6) the keys to this kind of tri, in my opinion are:
    a. use of lifting hydrofoils on the main hull daggerboard and on the rudder,
    b. the foils enhance the pitch stability of the boat but can also be designed to use an altitude control system
    that can be designed to allow the tri to fly with the main hull just above the water,
    c. The altitude control system will allow the main hull to fly earlier than it would otherwise AND prevent the boat from heeling too far by pulling down as necessary and automatically.
    d. The foils + altitude control system are why the boat will always develop maximum RM regardless of how little the crew may weigh and why it could be singlehanded at full power.
    7) Because of the foils and altitude control system a tri like this would allow the crew to sit near the center of the boat in the most comfortable way possible with no need for trapezes and running side to side.
    8) Because this boat would use a two foil system both foils would seriously augment the pitch stability of the boat.
    9) There are a three(or more ) ways the amas can be configured but one critical aspect is that they must be very small-approx 70% of total displacement-maybe less.
    a. a displacement ama would definitely use foil assist like the ORMA tris do or with an an adaptation of Hugh Wellborns DSS system using a pivoting horizontal board-both of which allow easy foil retraction. This is the "mini-USA" option!
    b. A concept I've been working on a little at time for several years is the ROH -rotating hull ama. If it proves out it would allow the same hull to be both a displacement and a stepped planing hull. It might have a top end speed advantage. Either this or "a." would probably be the best(and most marketable) system.
    c. a displacement ama using a surface piercing or t-foil designed to fly the ama(when the main hull is flying). Seems to me the foil would have to be easily retracted for light air,
    10) the boat could fold or just use plug in amas..

    Just a few ideas that I think could result in a design that could beat an F18-both on the water and in the market.
    I'd like to hear constructive ideas from anybody that's interested....
  13. Paul B

    Paul B Previous Member

    Really? An order of magnitude less? Can you quantify this?
  14. Chris Ostlind

    Chris Ostlind Previous Member

    Except that this isn't a tri vs cat discussion, Doug. It's an ideology indulgence about the Holy God of mythical performance for 18 footers that will go nowhere unless the conversation is about the inevitable plunge by our thread starter... that it is now steered to being equipped with foils. But you probably knew that, Doug. It's also about flooding a perfectly good general topic area with a particular name at the top of the list for even more personal indulgence. Much like talking to a used car salesman, you've been duped into a discussion that wound up being about something entirely different; the tri is lifting foil dependent, yet the thread title makes no hint as to that intention at all.

    Imagine, if you will, the vast number of multihull designers and enthusiasts that have come and gone over the last 50, or so, years. All the time while the beach cat craze was running nutso all over the planet, all that development intensity into perfecting the beach cat and virtually nobody bothered to take the idea to fruition as it is being put forward. A few small tris have been put forth that are friendly and fairly quick, but nobody really put the hammer down on an 18 footer. Hmmmm?

    Take some time to mull that one and give us the key to the city as to the secret, beach cat killer trimaran development cycle that we all missed while we sailed and studied the culture. You have done more in development of your foiling tri than anyone else has toward a beach cat killer tri of equal size and you are to be commended for that effort. Besides, I'll bet that it was fun... and you weren't trying to be production boat serious about your design/development efforts.

    I've drawn what will be a very light 20' trimaran with quite a hefty rig for its LOA and I do not really expect it to beat a squad of 20' beach cats, assuming that both types are sailed well. In some select situations it may do better than a cat, but all-around, I don't expect it to be faster. The difference isn't about the speed, it's about the different sailing experience offered by the trimaran compared to the cat.

    Speed equations are not the same at this size, just because they look good at the BMWO size of the spectrum. 18' tris are considerably heavier for the same market segment as the F18... or, they are decidedly more expensive due to exotic materials necessary to keep the weight down. That isn't a faster, more effective function from which to start an argument. Just because tris are wider, does not necessarily make them faster compared to a highly evolved cat, there's a whole lot to be said for lighter when it comes to whipping these dudes around a buoy and flashing off under screacher/spinny.

    Join the dumb parade if you want, but it's going to yield precious little of value, just as so many other of these exercises have done in the past. If you aren't tired of having this junk postured up your orifice, then by all means, sign-up for the full tour.

    You've got your opinion and I've just given you mine.

  15. Doug Lord
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    Doug Lord Flight Ready

    No, I can't accurately quantify it-at this point. An "order of magnitude" was ,technically" probably a poor choice of words. However, it serves to illustrate that the resistance to pitch of the tri can be much larger than an F 18 because the tri uses lifting foils on the daggerboard and on the rudder. These foils work in concert with the ama and the ama foil or planing surface, whose center of lift is ahead of the CG, to resist pitch in a way that is not available to an F 18. A completed design would be able to quantify this in precise comparative terms.
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