T20 -- New development class

Discussion in 'Multihulls' started by idkfa, Sep 26, 2011.

  1. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    len 6.1m (20ft) vaka, 5.52 m (F18) amas

    width 4.58m (15ft) - standing on ama side could still reach a centreboard or trip line on vaka, less than 7ft above.
    min. overall weight (ready to sail): 290 kg

    max. mast height: 9.15 m (F18)
    max. mainsail + mast area: 17 m² (F18)
    max. jib area: 4.15 m² (F18)
    max. spinnaker area: 21 m² (F18)
    Code zero on furler, and lowered to deck.

    Foils, any number and configuration, including lifting. But no single foil has more area than a current F18 foil.

    Rudders (F18), no T rudders.

    Folding system that allows self-rescue, eg. M23.

    Tiny cabin, min height 1.25m. Sitting height for coffee/tea or potty!



    Advantages over F18

    1)Faster from 15-18k+ winds, depending on waves.

    2)More off-shore capable; stable, dryer, easier to tack but mostly capsize/pitchpole a lot, lot less!

    3)No wires, still F18 righting moment+ with helm sitting in cockpit.

    4)110kg heavier but have lifting foils to off-set additional weight and increase stability/reduce pitching (max50% or less hopefully, Doug??)
     
    Last edited: Sep 27, 2011
  2. Doug Lord
    Joined: May 2009
    Posts: 16,653
    Likes: 322, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    F18 tri

    Hi idkfa, don't understand # 4.....? Why no "T-rudders"? One of the problems in small high performance tri's is not being able to fly the main hull( reducing wetted surface) until the breeze is over 15 knots because of the tremendous righting moment of a tri. By using a lifting foil on the daggerboard and one on the rudder it would be possible to take off in much,much lighter air..........
    Interesting concept-are any being built?

    Some parts of this thread my be interesting-I compared an F18 to an 18' tri: http://www.boatdesign.net/forums/multihulls/18-trimaran-vs-f18-catamaran-33201.html
     
  3. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    Doug, I edited #4, hope it reads better now.

    One of the main ideas, is to keep cost down, and having T rudders means we are moving away from the F18 for parts and in concept. ie 100% possible foil assist. That should to be limited to more like 30-50%; the real advantage of tris over cats is stability and not speed, so no point trying to do better what a beach cat is best at. The AC45 should be reduced to chopped-liver off-shore, if anyone is foolish enough to race one out of the lee of the shore.
     
  4. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    I'll have to re-read your thread, F18 v T18, but for me a tri by definition has three hulls and not "2 hulls and a weight-pod". I see benefit in NOT flying the centre-hull, like increased stability, reduced pitchpoling and no chance of capsizing. Which really is a drag when you are racing; who pitchpoles the least wins? that's silly! I prefer to sail while enjoying the speed, and not being afraid that any moment we can start pitchpoling/capsizing and there is little but chance to be done about it.
     
  5. Doug Lord
    Joined: May 2009
    Posts: 16,653
    Likes: 322, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    F18 tri

    ==================
    Each to his own, I guess. I'm convinced that with the right design small trimarans can beat beach cats not only by being faster but by being easier to sail, much more comfortable and much less likely to capsize or pitchpole. Of course, in my opinion, the proper use of lifting(up or down) foils is critical to achieve those goals.
    Good luck with your concept!
     
  6. Ad Hoc
    Joined: Oct 2008
    Posts: 6,577
    Likes: 598, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    I got all excited when i saw the T20....didn't think cricket had anything to do with boats! :eek:
     
  7. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    What's cricket?:p
     
  8. gypsy28
    Joined: Mar 2010
    Posts: 218
    Likes: 25, Points: 28, Legacy Rep: 120
    Location: NSW Australia

    gypsy28 Senior Member

    Well T20 is not REAL cricket ;)
     
  9. Ad Hoc
    Joined: Oct 2008
    Posts: 6,577
    Likes: 598, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Ahh..depends upon ones perspective.

    It's more like playground cricket to me..but, it is still fun to watch :)
     
  10. gypsy28
    Joined: Mar 2010
    Posts: 218
    Likes: 25, Points: 28, Legacy Rep: 120
    Location: NSW Australia

    gypsy28 Senior Member

    Pretty much my views exactly, great minds think alike !
     
  11. Corley
    Joined: Oct 2009
    Posts: 3,757
    Likes: 182, Points: 63, Legacy Rep: 826
    Location: Melbourne, Australia

    Corley epoxy coated

    It's an interesting formula that your proposing but I cant see many people building boats to those specs. If a commercial manufacturer got excited and turned out some boats you would have the core for a competitive class I dont see how a manufacturer could put together a decent business case to build such a specialised boat though. Its all fine in theory but a number of people would have to come up with deposits before a builder would ante up with the capital to make it happen.

    Look how few C class cats are in existence they are a premier, well established multihull development class but still not many around and fewer still that are actually competitive.

    I think there is more chance of the new Bradfield foiler getting a start they have at least built a prototype, there is a long path from there to production though. As a one design racer it might have some promise should it actually be viable to build the boats in any quantity.

    btw for cricket to be worth watching surely it's got to be at least a one dayer that twenty twenty nonsense is more like popcorn for the masses.
     
  12. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    Thanks Corley,

    "Build it and they will come"

    Totally agree with a core critical mass to launch it. Start work on details; like lifting foil option position and size.

    With the success of the F18 class, there are hundreds of donor boats out there. Maybe some home built plans for marine ply and form core construction for a centre hull? A strong 100kg vaka should be achievable (without female moulds) with some thought. ie. folding aka connections?

    The real shortfall I see with all small off-beach tris is self-rescue?

    It would be really nice to see a small tri (limited dev?) class complimentary to the F18 and Mini650. 20ft? 23ft? square or 3/4? but I think price is the make or break factor and that's probably between 20-25K? Too much to ask?

    Any word on The big Weta?
     
  13. Doug Lord
    Joined: May 2009
    Posts: 16,653
    Likes: 322, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    F18 tri

    =============
    idkfa, see my " self-righting trimaran model thread". I believe it is possible to design a small(18') high performance tri that would be self-righting. I'll know more after a while......
    I agree 100% that a development rule tri would be interesting as long as the rule doesn't have too many serious arbitrary restrictions. In my opinion ,beam should be either unlimited or a figure like 1.3 length(like Hydroptere), foils could be limited to "foil assist" only requiring the ama to at least touch the water or they could allow full flying.
    A pet peeve of mine has always been that most tri's under 20' are not designed with the maximum advantages a tri configuration has and therefore small tri's have got the rep of being slower than beach cats: doesn't have to be so!
    Again, good luck!
     
  14. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    Doug I see each with its own role.

    F18 as day sailing beach.

    The tri as off-shore capable with overnight possible - fair conditions.

    Mini650 trans ocean - storm ready.

    Also I don't doubt that it is possible to trick-out an beach tri 18 that will smoke a cat, but I more concerned with mass appeal, cause to me a tacking duel on a mono (ie. numbers) is more fun than speed.

    Good luck with your self-righting trimaran model, please don't patent the results!
     

  15. Willallison
    Joined: Oct 2001
    Posts: 3,590
    Likes: 130, Points: 0, Legacy Rep: 2369
    Location: Australia

    Willallison Senior Member

    Well... I have to say I'm surprised.... I always thought that T20 cricket was designed to appeal to those with a short attention span... just the kind of folk that linger around here!:p:p:p

    sorry... back to the topic at hand....;)
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.