T20 -- New development class

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

  1. Doug Lord
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    Doug Lord Flight Ready

    T-20

    This is the first post of this thread:


     
  2. Doug Lord
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    Doug Lord Flight Ready

    =================
    You desire fast racing but your proposed rules create a same old-same old trimaran that won't beat a cat and might have trouble with state of the art monohulls!
    Dumbing down rules to create trimarans like those that already exist seems like going no where.
    The trimaran platform is ideal for a fast, easy to sail and comfortable boat but if you're not going to use the advantages such a platform offers, whats the point?
    In a class that allowed square or oversquare platforms and the sail area that they could handle, boats could fly the main hull in a 5-6 knot breeze as well as flying the whole boat in that same wind if that was the way you wanted to go.
    The "problem" with square or oversquare is that to meet their potential they need a foil on the daggerboard and a rudder t-foil to give them the ability to fly the main hull in lite air as well as to develop the pitch control required.
    This is the kind of trimaran that could beat beachcats -and that w/o flying the ama.
    Weight can be managed with smaller than "normal" amas that at a minimum use "C" lifting foils that like the Mod 70's would lift 80% of the boats weight.
    There is tremendous potential for an innovative design for a 20' tri-I'd hate to see it squandered by a shortsighted approach to design.
    --------
    I think there is tremendous potential in the development of a class like this for co-operative foil design and building-so that everybody that wants one of these boats would have access to state of the art foils and engineering consultation to be sure that the boat is suitable for the foil system. Boat design could be as individual as desired but ,perhaps, foil design and construction could be a "one design" component of the class-allowing everyone the same access to state of the art technology. Doing the same old same old simply won't cut it......
     
  3. P Flados
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    P Flados Senior Member

    Wanye,

    The width should really not matter as a performance limit. The performance would be effectively limited by:
    • mast height
    • sail sizes
    • minimum weight
    • "one hull in the water"

    As I think about it more, I do have a concern with concept. The size of the boat indicates a desire for open water capability. However, I doubt that people would have the disciple to insist on something should probably be considered essential for safe sailing:

    • Solo capsize recovery capability in choppy conditions.

    Even if sailed with a crew of 2, you really can not count on both to always be capable/competent at recovery actions. Solo recovery can be engineered in, but it would be complicated and include items such as:

    • Sealed high volume mast (possibly wingmast that is foam filled in the upper 25%)
    • Main hull designed with ample fixed flotation (foam) up front and in back
    • Amas with a very specific amount of fixed (probably foam) flotation, but open vent/drains such that the boat will naturally lay on its side with main hull and mast floating on the surface of the water.
    • Provisions to apply the leverage required to go from on its side to upright

    If solo capsize recovery was a mandate, it would probably prevent going much wider than you proposed.

    I am not sure how practical it is at this point to talk about building open fleets that would include the above along with beach cat performance and a reasonable ability to launch from a trailer.

    I am not trying to be negative. I see it as very doable to build a 20' tri that would be fun, fast, stable and not outrageously expensive. At the same time, a class is unlikely to be a real success unless it is reasonably safe and trailer friendly.

    I am sure there is a level of performance that can be achieved with the more practical aspects. I just know that it would probably work out better to start with a prototype effort where you build in the safe/practical stuff first and then see how much performance can be achieved.
     
  4. waynemarlow
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    waynemarlow Senior Member

    Width is always going to be a contentious thing in this discussion, but if we want to see a successful formulae establish itself then we are going to have to include present manufacturers, without them, sorry but it would never get off the ground. The saying " trying to herd cats " would be appropriate at this point in time. If you put a bit of food out, then just sometimes, you can be a cats best friend.

    At the moment every manufacturer is thinking OD, we here on this forum are not even on their horizon. So as much as we want to bang on about foils and over square boats if we carry on as this discussion is heading then we may as well forget the manufacturers now.

    Me personally I think that if we limit ourselves to not what we want but to what a successful formulae could be, then we need to drop a lot of our aspirations now. Yes in time when there is successful formulae happening we could introduce a more radical boat that has all the bells and whistles, but not yet.

    So Doug what is it going to be, continue to bang on about foils and over square to such an extent that most readers will move on, you do have a track record of this, or are you going to constructively help develop a formulae class that could in some future time, bring about real change. Sometimes small steps are the most successful.
     
  5. Richard Woods
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    Richard Woods Woods Designs

    I agree with most of P Flados' comments

    Quick replies

    To answer the off topic one. My 10ft Tryst is based on my Duo dinghy. The main hull is two sheets of 4mm ply, both outriggers come from one sheet of 3mm. Plus a minimal amount of lumber and maybe 3kgs epoxy. We built a complete Duo in two days. I made my own Tryst nesting, so the whole 10ft x 7ft trimaran fits in the back of out Toyota Tacoma pick up, even though it only has a 6ft long bed

    I really built it to use as a fun sailing boat I could carry on our Skoota 28 powercat

    So far I wouldn't make any changes because it does exactly what I intended it to do.

    See photos and videos here

    http://sailingcatamarans.com/index.php/designs/27-trimarans-under-25/428-tryst-trimaran

    Since late August I have had fun sailing it in British Columbia, Oklahoma and Mexico
    ================
    To the main topic.

    Even racing boats are not just for sailing. In this size no one will have one if it is too expensive. When I started the micro class I said the boats should cost the same as a second car, not a second house. Later I wrote that people didn't seem to know the price of cars...

    And definitely a boat like this must be trailable and thus quick and easy to rig and launch, possibly even off a beach, as we do with our Strike 10/15/18. Not everyone has a big wide slip empty of other boats that gives time to rig a 20ft wide boat. And of course having the ability to sail on/off a lee shore and beach the boat makes it more attractive as a day sailer.

    The mast is probably the single most expensive item, and the hardest to source. Delivery costs are also high. So it makes sense to use existing masts, hence the mast length limit, 9.15m, or 29ft or whatever.

    I would expect many boats to use a ex beach cat mainsail, but most will get a larger genoa and everyone will have a screecher and/or assy spinnaker.

    Curved foils make sense and is what I was assuming when I said "one hull in the water". They have been around a long time, we drew a trimaran with them when I was working for Derek Kelsall in 1979/80

    I have yet to sail against a "sportsboat" monohull that can beat a multihull to windward, even though they might have similar off wind speeds. For example I did the 3 Bridge Fiasco race in San Francisco a couple of years ago on a F27. The J70's were the same speed off wind but fell over on the beat home and came nowhere. You can read the report here

    http://sailingcatamarans.com/index.php/articles/10-race-reports/270-three-bridge-fiasco-race

    Even my live aboard Eclipse catamaran was faster than similar length Mumm 30's to windward. But the Mumms caught us up offwind.

    I don't think self righting should be a requirement. Many people cannot self right Hobies or A class, never mind monohulls like this one.

    https://www.youtube.com/watch?v=99n-_Eu4-m4

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  6. P Flados
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    P Flados Senior Member

    Richard,

    Your boats are very practical in a lot of ways, but I think you underestimate the selling power of a boat designed for solo capsize recovery.

    I know it is takes some extra effort, but it is a heck of a lot easier to think about with a tri as compared to a cat.

    A cat has physics working against it when it comes to recovery. Even if you keep it on its side by use of a sealed high volume mast, it takes a bunch of force to get that mast up out of the water (and usually the wind will be fighting you making it even worse). This combined with the ever present risk of a capsize while flying a hull is a big part of what limits the appeal of a the larger beach cats.

    For lots of cases skipping capsize recovery is ok.

    One reasonable choice is to just maintain good margins for capsize avoidance in the first place. This does not really fit into the mindset that would go with competing against boats willing to sail with only one hull in the water.

    At the other end of the excitement spectrum, are those that want fast and are willing to live on the edge. For this crowd I see no reason to not stick with the proven capabilities of a big beach cat.

    Those interested in this style of Tri seem to want "the thrill of a fast beach cat" but also want a boat that is more stable and involves reduced physical demands. The above gives you a little bit of "safer" from the more stable aspect, but you get a lot of improvement in safety with solo recovery ability.

    It would take some effort. It might even limit light with performance a little if the mast needs to be less tall.

    I am probably ranting and a just a lone voice on this subject. I tend to be very self reliant. I am also an engineer that feels that promoting others to being safe and self reliant is not such a bad thing.
     
  7. Richard Woods
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    Richard Woods Woods Designs

    I look at it from a professional point of view with liabilities in mind

    Suppose I claimed "This boat is self righting" or "This boat is crew rightable by one person" and then in some extreme condition it wasn't. Maybe I test it and it works in 30 knots and flat water, but not in 45 and with a sea running. Or maybe a 60 year old fat man couldn't do it, but a 25yr old line backer could.

    Suppose the crew righting system added 20kgs to the weight, would people want it?

    But being positive, if you got a rating advantage by proving you could right the boat then maybe???

    I guess you have seen this (with my old house in the background!)

    https://www.youtube.com/watch?v=655COFngiQA

    and here when he races (sort of, read to the end)

    http://www.yachtsandyachting.com/news/164235/Firebird-Orion-goes-Round-the-Island

    I crewed for Graham Goff in a sister ship when we won the 1994 UK Championships

    So questions: Why don't the Extreme 40's etc use this system

    Is this too slow a boat for Wayne?

    Will a T20 be faster? More seaworthy?

    RW
     
  8. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    T-20

    =========
    I'd like to see something like idkfa's idea of a T-20 succeed with maybe two divisions- High Performance and Daysailing or something like that.I think my earlier suggestion about trying to work out a co-operative way to provide foils is worth considering.
    One thing that bothers me is artificial restrictions that attempt to limit what is possible especially if the idea is to develop performance trimarans. People tend to place limits within their comfort "box" rather than on realistic limits for a performance trimaran. Is it going to be a development class or a one design same old same old? Someone earlier in this thread or in Raps thread suggested two divisions-might be worth considering.
    In that thread the Pulse 600 was mentioned-well it's price is around $33,000 unless it's gone up. That's a lot of boat if you're reasonably skilled....
     
  9. Richard Woods
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    Richard Woods Woods Designs

    Well let's put our money where are mouths are, shall we?

    I'd be happy, keen and willing to build a "Daysailing" T20, ie my Strike 20 using F18 (say) outriggers. However I cannot do that until I have sold at least one of my other Strikes, the 15 or 18. Right now I have four boats, or 11 hulls, depending on how you look at it. That's too many!!!

    So how about you Doug, will you design/build and sail a foiler?

    Let's make the first race the Everglades Challenge 2016 shall we? That's near you. Although better for me, as it's only 1000 miles to drive, would be the 3 Bridge Fiasco, a few weeks earlier. Or we could do both?

    What do you think?

    Richard Woods
     
  10. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow

    I already have put my money and labor where my mouth is with the test model and if the testing of the Fire Arrow continues to go as well as it has gone so far, AND if I can raise the money I will build the full size version of the Fire Arrow-foils and all. The Everglades Challenge is probably not suitable for the Fire Arrow but I'd have to study it more carefully-that would sure be fun in the right boat. I've discussed doing it with my Crossbow fl monohull which would be suitable and very fast(for a monohull). But neither boat is built yet(though the main hull for the Fire Arrow is still available and with some mods should be suitable).
    There are numerous other courses/races that would be suitable for both boats and it would be a great race-at least for me!
     

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  11. waynemarlow
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    waynemarlow Senior Member

    No you definitely are not a lone voice, one only has to talk in the bar at my local sailing club and the buzz is, what can we move onto after fast beach cat racing. We all acknowledge whatever that maybe, won't be as fast nor as adrenaline filled but we do look foward to some sort of fun filled sailing that is not in the Flying Fifteen style of boat.

    So I think that these little T20's may well fill that void, but we are just a small percentage of a potential market and thus the manufacturers such as Corsair will opt for safe and easy boats which the average sailor won't tip over nor get into too much trouble when things enevitably go wrong.

    So we will end up with slightly under powered, slightly narrow,slightly safe boat and to be honest that's not a bad call. No sailing club will want anything on their pitches if that boat is going to unfairly call on limited resources.
     
  12. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    T 20

    ========
    What kind of boat would do that?
     
  13. waynemarlow
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    waynemarlow Senior Member

    An over square 20ft Tri that can only be righted by towing it backwards as per the recommended method to right most Tri's for example, might take an hour to right, when safety crew and boats are needed elsewhere, that Tri may well be abandoned until after racing has finished. Get 3 or 4 knocked down in a squall and you have full on safety problem. No club will want that on a regular basis.
     
  14. idkfa
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    idkfa Senior Member

    T20 prototype built (and moulds too but couple mods pending). Folding amas - trailer-able. Curved lifting foils (old style - limited lift, more for stability). One-person capsize recovery is designed for but not tested, and I agree is absolutely essential, hence the beam restriction.

    Hi Richard, 2016 sounds about right, got distracted with a mono.
     

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  15. Doug Lord
    Joined: May 2009
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    Location: Melbourne, Florida

    Doug Lord Flight Ready

    T 20

    idkfa, that is a beautiful boat!! Can you post more of the details?
     
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