Randy Smyth's Trimaran

Discussion in 'Multihulls' started by Doug Lord, Mar 9, 2011.

  1. patzefran
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    patzefran patzefran

    A class cat

    You are right, Gary, 9 m is not 33 ft but 29.5 ft, length of my current Bim V1 A class cat mast.
    However I have doubts about the weight of 75 kg for compounded plywood A class cat.
    To my knowledge, wooden / aluminium A class cat, even built very light were over 100kg, 220 lbs (You can ask Ask John Lindahl, I built one of his design in 1985). Using glass polyester or vinylester sandwich permitted to reach 90 kg. Only carbon sandwich, plus carbon mast, beams and foils permitted to go under 75 kg. I speak about racing boats able to sail up to above 20 kt of wind !
    Cheers

    Patrick
     
  2. Doug Lord
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    Doug Lord Flight Ready

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    Both the light weight tri's I mentioned(Sizzor and the Ultralight 20) are capable of sailing in those conditions from what I understand.
     
  3. Ilan Voyager
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    Ilan Voyager Senior Member

    The size of the lake has nothing to do; in summer the prevalent conditions for racing are very light winds and flat water so you build a boat for those conditions. And the scantlings are done accordingly. It would be useless to build the tanks we need in the Channel or North Sea, where the prevalent conditions are exactly the opposite.

    Conditions for regatta in Northern Europe are from the uncommon calm to the very common fresh wind with waves height determined by the tides. I have raced several times in North Brittany with a solid 30 knots wind and a very choppy sea of around six to eight feet when the wind is against the tide current (the tides height range from 20 feet to 35 feet in North Brittany with currents up to six knots).
    So you can imagine that the scantlings are not the same...We have broken the structure of several catas; Dart, KL17, BIM 20 and Hobie 18.
    My 162 kg stressed plywood Tornado had never broken spite having a very hard life. The fun of our sailing group was jumping full speed the 12-16 feet waves with a 25 knots wind of the "shallows" of Triagoz in front of Plougastel with everything that floats and has a sail, even Optimists. It's a good test for structures and repartition of safety foam volumes...A lot of bruises and a few broken bones also.

    With a friend, I have made also one class A Jon Lindhal 1985 and I agree with patzefran; with the greatest care and the best choice of 3 mm okoume plywood 3 plies of 1 mm; 98.5 Kg. Commonly around around 100-103 kg, as Lindhal announced. It's impossible to get a reliable Class A in plywood at 75 Kg.
    My last 18m2 (10 feet wide) 1992 with "industrial" carbon beams, carbon wing mast 10 meters, titanium and carbone hardware, and hulls in stressed plywood 3mm was 90 kg ready to sail, and I truly suffered to get this weight...

    The nowadays high level Class A are ultra specialized for very light winds. In choppy seas and a good breeze the DNF are numerous.
    The general conditions at the Everglades are pretty mild and even the Scissors breaks often. That shows that the scantlings are already too light. 25 pounds more would not hurt the perfs and will improve the reliability.
    But I can tell you that at the Round Texel ( http://en.wikipedia.org/wiki/Round_Texel) the boat probably will desintegrate. The very funny 22 feet Trifoiler by Hobie was killed by its fragility in European waters and it weighted 320 pounds...

    In reality some reasonable weight doesn't hurt: first because some inertia can help you in a choppy sea as shown by the 190 kg F18, second because breaking at every race is frustrating, third because that permits to build cheaper boats. Better to concentrate on the tuning and getting the most of the boat without worrying about unreliability.

    Surely Randy has great fun with his tri but I doubt that in the actual configuration he is able to beat the cream of the 20 feet cats in any condition as these cats are able to manage. You need power and visibly this tri is not powerful, it is sleek a good option for light wind. When the F40 Adrenalin was pressed hard by Biscuits Cantreau in the F40 champoinship (1989?), the tri began to have structural problems with the "hinged" amas and showed an irremediable lack of power because of its 110% amas, mainly upwind. There was no match, Biscuits Cantreau was able to fly on one hull with no structural problems and that is pure speed.
     
  4. Gary Baigent
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    Gary Baigent Senior Member

    Your knowledge is truthful and practical, Patzefran, and who am I (never built an A) to disagree ... but went through AYRS catamarans 1967 and John Mazzotti's A Class Unicorn, one of the earliest A's, has a printed weight of 120 lbs, built by Trowbridge and sons - cost was 300 pounds.
     
  5. Ilan Voyager
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    Ilan Voyager Senior Member

    The Unicorn catamaran weighted 220 pounds. I'm very sure. AYRS bulletins are known for their very numerous mistakes and are not very reliable.

    Sorry for you guys but lakes are lakes, even if they are big, they can have their bad days and tempests, bust most of the regattas sailed in summer in the Great Lakes (the inland seas) , Geneva lake, Garda lake are by light weather with little wind and flat waters. It's the prevalent condition, so the boats are made for the conditions you'll find most of the time during the regatta season; very light and big sail surfaces with rather tall masts. Some sea places like San Diego are similar.
    In lakes there are not tide currents, not big oceanic fetch, nor drastic changes in depth that can create very difficult seas to manage. In West Europe the conditions are very different because of the sea behavior and west winds.

    But images talk better than words.

    Texel Island is in Northern Holland. The race is about 100 km long. The Tornadoes do the race in about 3 hours but cannot save the rating against the F18. On the distance the mean speed is around 16-18 knots.

    http://www.youtube.com/watch?v=knY08LrNyHg
    Extreme Catamaran Sailing at Round Texel Race 2011

    http://www.youtube.com/watch?v=ryp_RzgIZsc
    Round Texel 'EXTREME Catamaran Sailing' 2012 HD by SailVideoSystem
    A catamaran F18 sailed by 2 girls won brilliantly in 3 hours 10 mn.

    Now tell me, what can do the Scissors in that? will it flatly win? or break in 2 pieces?

    http://www.youtube.com/watch?v=8zerhvg5OU4
    Tornado Class Catamaran Big Wind. An exercise I made several times for the fun with my preferred catamaran buddy, a sweet girl 6 feet tall 170 pounds of muscle.
    Can the Scissors sail in these conditions?

    That are the questions. My answer is no. Scissor is made for light winds in mild sea and has not the strength nor the power to manage that. Your opinion?
     
  6. Gary Baigent
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    Gary Baigent Senior Member

    Better let Randy reply.
    But offer my viewpoint.
    So what? Scissors is very light, yes, designed for the conditions. Has unique folding system, repeat: designed for the conditions, but a tricky affair, hence breakage.
    Nevertheless, Scissors won one year. Can't be all bad. In fact, bloody fantastic.
    End of story.
     
  7. Ilan Voyager
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    Ilan Voyager Senior Member

    You're right Gary. Randy has a legendary winning record. The Scissors is not bad, I'm sure that it's very good a certain kind of sailing conditions. It's not an all around boat.

    That I wait it's a tri able to do with the beach cats that Cantreau and Adrenalin did in the F40 with the cats in straight competition, in any condition of wind and sea.

    The 20 feet trimaran able to beat the cats in a regular basis in competitive races like the Texel Round is not made for the while. Maybe it won't never be done because of cost and technical problems in this size.
     
  8. patzefran
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    patzefran patzefran

    Gary,
    Thank you for your kind words, I say the same for you ! A friend, dead now, owned a professionally built Unicorn, monolithic glass polyester. To my recall, she was over 100 kg . From "Multihull Sailboats", Edward Cotter, printed in 1971, original plan was designed by John Mazotti in 1967 for 4 mm stressed plywood, with una rig, alloy beams and mast (no weight mention, nor for the Australis). Not the lightest materials ! May be I am completely wrong, but more probably AYRS records was somewhat optimistic. Beware printed matter !
    Cheers

    Patrick
     
  9. Gary Baigent
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    Gary Baigent Senior Member

    For sure a solid glass A Class would be way heavier than a tensioned ply example, maybe 40% more. I checked the 1967 AYRS again; there is another mention of the Mazzotti A being 150 lbs - so there are two figures in the same publication; the 120 lb figure referring to a reprint from Yachts and Yachting magazine (in the AYRS). Who was right?
    Mazzotti was a lightweight building specialist (also with his Manta B and C's) and those '60's blokes like March, White, MacAlpine-Downie, Cunningham, did really impressive and advanced pioneering work in cat design and light wood construction. Look at Dashew's Beowulfs for example, decades ahead of the then established US thinking.
    So a Smyth altered featherweight A Class to 20 foot main hull with exotic, lightweight, minimalist beams, floats, foils and rig --- 168 lbs seems perfectly reasonable to me.
     
  10. patzefran
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    patzefran patzefran

    Gary.
    I have already agreed 168 lbs (in a precedent post), according to the interview of Randy Smith, is likely the weight of Scissor . Does Randy finished any race with this boat, I don't know ?
    Speaking of A Class cat, it seems also Graham Shanton A class cat (New Zeland) in the sixties was 68 kg . But soon was added to the A class Rules a minimum weight, according to the current avalable materials, in order to have reasonably strong boats. I have not the history of this minimum weight, but I know it has evolved in the recent past from 90 kg to 80 and then 75 kg. So Graham Shanton boat nowadays would be outside A class cat rules. I don't know if it would be competitive with current A class cat (likely in very light wind).
    My 76 kg Bim Vcould have been surely built lighter, but after 5 years I can see no sign of ageing, which was not the case with my former (heavier) boats.
    Best regards.

    Patrick
     
  11. Doug Lord
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    Doug Lord Flight Ready

    =====================
    As Gary said you should ask Randy. The link is on the first page of this thread and he has answered other questions. From one of those answers:

    Clearly Sizzor has evolved into a rather well rounded performance trimaran with a reasonable degree of safety. Randy Smythe 2013

    I don't think a trimaran has to be designed to sail in the North Sea to be successful in the US. Here, in many areas the wind is not above 10 knots very often. Trying to market a 400lb tank to people sailing in these areas may be one reason high performance sailing of small boats is not so popular here.
    And why don't you ask Ted Warren the same questions- I believe he has said that his boat is designed to be sailed in any conditions a cat can sail in.
    The bottom line is that there is good reason to believe that a small trimaran can be designed to beat most small catamarans with an unmatched level of comfort.
     
  12. Doug Lord
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    Doug Lord Flight Ready

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    Patrick, I think Randy won against a Tornado(and everybody else) in 2011. You can go to the Everglades Challenge site and look it up in the archives.
     
  13. Ilan Voyager
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    Ilan Voyager Senior Member

    Doug, for the US market I've already said that in another thread; mostly light wind so no need of an European "tank". The high level races are in Europe and Australia. And compared to these countries, the "density" of multis in the States is rather low.

    About the weight of the Unicorn and older cats Patzefran has described the situation of the class A. Some claims in the 60' and beginning of 70' are improbable. At 68 kg a Class A cat in plywood, glued with resorcine and just painted won't last. I do not see the advantage of wasting 300 hours of work for a kleenex boat.

    The Unicorn Internet site does not give any weight in the technical specifications. Anyone who has experience in building boats and specially small cats in tortured plywood will say that with care, the best French 3mm okoumé plywoods and a good design, a class A with reasonable strength and durability, is around the range of 90-100 kg with alu mast and beams. Under that weight the cat is fragile and not durable. The great advantage that in plywood the boat is relatively affordable, but totally not competitive for racing at good level in class A.
    Class A went lighter and lighter because of the limitation of 13m2 of sail and width, in conjunction of most races done in light wind. It's a normal trend for a boat destined to pure regatta around 3 buoys in protected waters. But the boat remains very elitist, as being too specialized.

    Without these limitations, and 2 guys on the boat you get a F18...The rule is very well made and permits to have strong boats (180 kg minimal weight, 130 kg for the platform with a max of 7 kg of corrective weights) at a "reasonable" price. The boats are fun, fast, durable and multi use. That demonstrates that lightness is not all...
    Yvan Bourgnon has made a 24 hours record of 344 miles and crossed the Channel (about 200 km) in less than 8 hours. That gives an idea of the possibilities of an F18. 14 knots mean speed in long distance runs for a 18 feet is interesting...The success of the class is very good.

    The problem is to design a trimaran with the same SOR and able to beat these cats every day...A rather fragile ultra light tri is not interesting for Europeans. A 170 pounds 20 feet tri can't be strong, it's a basic problem of strength material (I have some knowledge about, theoretical and practical). The best demonstration I'm wrong, is to go in a very competitive race like the Texel Round with the best Europeans, go WOT for hours, do not break anything and eventually win or be among the head group.
    Sorry Doug but the Everglades is a nice race, but not a competitive one. Beat one Tornado means nothing as we do not know the value of the guys on the cat. You can't draw any conclusion. Beating the 200 best F18 and 20 footer would mean something...and beating them again and again, whatever the conditions, would show the superiority of the design and building methods. Otherwise it is a pointless discussion.

    For just fun, it's another matter. Monodromic proas are very funny but not competitive, but the happy owner having fun do not care. I'm sure that the Weta tri is a very exhilarating boat in a sunny day at the beach.
     
  14. patzefran
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    patzefran patzefran

    Thank you Ilan Voyager, I am in total agreement with you.
    Doug Lord :
    I agree with you that a Trimaran would be attractive. I am getting old and it becomes difficult to race on A class cat against Younger people. But when I try to design a trimaran solo to beat (or at least equal) A class cats in allround conditions I quickly find this impossible. Why have three hulls when you can have only two and fly most of the time on one ? There are no solo multihull equivalent to A class cat on the market, Tris like weta are dogs in comparison. If you know a design, please tell me.
    Cheers

    Patrick
     

  15. Doug Lord
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    Doug Lord Flight Ready

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    Ted Warrens Ultralight 20 could be considered. It is very light and is designed to fly the main hull. The "inexpensive" version has carbon hulls and aluminum cross beams-at 15 grand(US). It is also designed to be able to use ama lifting foils. I think it is one of the best trimaran designs to come along so far as a high performance 20 footer. It will be interesting to watch the progress with race results as time goes by.
    ----
    There is a major design conumdrum with small trimarans and it is why there are so few designed to fly the main hull. The problem is the RM that can be generated by the tri. With such great RM(righting moment) tremendous SA(sail area) has to be used to be able to fly the main hull in under 12-15 knots of wind and that large SA can make handling very difficult.
    I believe I have found a solution that does not require ultra light weight and I am building a model to test it. The idea is to use a bi-foiler arrangement on the main hull with a curved "L" foil(stolen from TNZ because of its variability, great lift, and automatic altitude control similar to a traditional surface piercing foil) on the amas. By making the amas relatively small but with adequate ultimate buoyancy the weight can be kept down to about the same as an F18 for an 18' tri 22' wide and all carbon. Because of the foils on the main hull(main foil wand controlled) the hull will fly in 5-7 knots of wind. Because of the oversquare beam the boat can be singlehanded in any wind up to 25 knots w/o reefing. The wand controls main hull altitude and hence the angle of heel of the whole boat which would be set at 10-13 degrees.
    This foil system which is applicable to almost any size of small tri-12' concept model in the pictures below. The system is fairly unique since as soon as the main hull flys(due to lift from the foils) the foils begin to unload due to the heeling force from the increased pressure due to speed. That means that the induced drag of the main foils(drag due to lift) significantly reduces and the ama foil begins to support the whole boat. The main foil and rudder foil are then primarily for pitch control and angle of heel control. It is a system with a great deal of potential especially with small tri's and really opens up the trimaran platform to its full potential in light and heavy air. Flying the main hull in light air is critical to this increased performance and would not be possible w/o the foils.
    This is 2013 and there is only ONE production trimaran 20' and under that is designed to fly the main hull and use ama lifting foils. That will change and I hope my foil system will be part of that change.

    Pictures-This is a 12' design with a 17' beam, 175 sq.ft of sail(plus a screecher). The boat would use a combination of planing ama and lifting foil on each ama :
     

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