Trapeze as a design decision?

Discussion in 'Sailboats' started by 500Lonepine, Sep 8, 2013.

  1. 500Lonepine
    Joined: Sep 2013
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    500Lonepine Junior Member

    Hi,

    I know there is no direct correlation between a boats speed and wether it sports trapeze. But could someone give me a little insight into what a boat like the Flying Scot does not come outfitted with one?

    Does this simple design decision have anything at all to do with speed?


    Thanks!
     
  2. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Probably not with the Flying Scott-likely to be more related to the target market and the anticipated use of the boat.
    Using a trapeze can be directly related to speed because it adds righting moment that would be hard to achieve in any other way. More RM= more power to carry sail= potentially more speed.
     
  3. messabout
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    messabout Senior Member

    Te Flying Scot is pupose built and rigged for family outings. No hiking allowed. These are big commodious boats that are very good for their intended purpose. They go pretty well but sheer speed is not the principle aim.

    There are hot rod boats such as 49ers, FDs, and many more, that are over rigged and thus difficult to sail upright in much of a breeze. There are several ways to get some human ballast outside the boat so that the boat can be kept reasonably flat. The trapeze is one method, winged boats are another, and finally hiking planks such as that used on International 10 meter canoes, and oddly on some Bahama Smacks during race week. All of those variations are for the same pupose. Keep the boat upright while using too much sail for the exisring wind conditions. In the end the boat goes fasrter because the sails are more powerful..
     
  4. gggGuest
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    gggGuest ...

    Probably best to think of it as market placement.
     
  5. Skyak
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    Skyak Senior Member

    Trapeze is the lowest cost way to add righting moment which can translate to thrust and speed. It adds the least weight, and is relatively easy on rigging because the ballast hangs directly off the mast. Its cost is primarily in skill and safety. Personally I like traps more than wings because you can work with your legs in variable winds. Being strapped to the boat is a safety issue and traps are hard to handicap since they accentuate body advantages.
     
  6. gggGuest
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    gggGuest ...

    Umm, if I understand what you mean correctly (and am not sure I do) then that's not quite correct. Because the weight of the trapezing crew hangs off the mast it creates a significant challenge for rigging because the effect of the crew going out on the trapeze is to unload the windward shroud which dramatically reduces the effectiveness of spreaders, assuming the mast has them.
    Before high rig tensions were in use this could create a situation where the reduced support for the mast meant that as soon as the crew got out on the mast the rig would depower, and thus the crew would have to get in the boat again. This can be worked around by using a rig with diamonds instead of spreaders (RS600, Laser 2) or by using very high rig tensions, which can cause problems with hull longevity. 470s especially used to be notorious for short lived hulls for this reason, although construction has improved a bit in recent decades.
     
  7. Skyak
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    Skyak Senior Member

    I was not thinking about mast bend when I made the comment. I can see your point on a tall flexy mast with swept-back spreaders -which is most high performance trap rigs. You would be inadvertently adjusting stay tensions.

    I guess I just assumed rig tensions>>trap forces. Would there be any problem if the spreaders were in line?

    When I think about high performance sailing it always amazes me that expensive, complex (not fun) skills like mast bending and sail making are embraced while technologies that simplify or cheapen performance -multihulls, wing mast, lifting foils... are discouraged.
     
  8. gggGuest
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    gggGuest ...

    Yeah, its always an issue. For the spreader to do anything it must be affected by the rig tension.

    Now consider a boat with two folks hanging out of the boat on toe straps who weigh 300 lbs between them. Their cog might be 50% further out than the shroud position, and its pretty much all going up the shroud, so that's what, maybe 450lbs going up the shroud if my brain hasn't fried.

    Now one hits the wire: immediately that 450lbs is down to 225lbs. The amount of rig tension required for this not to affect how the spreaders work is prodiguous: I used to run something like 600lbs static in one of my boats, and the crew loads were on top of that. That sort of load takes a bit of managing, especially when you consider the matching compression loads down the mast as well (and which the crew weight still contributes to).

    I'm rather bemused that you think second hulls and lifting foils might cheapen performance. My immediate guess would be that both would add at least 50% over the cost of a single hull. As for wing masts, well, if you mean the the short version that have a sail behind, then they are about the most complicated bits of kit to construct and tune that I have ever had dealings with. Even though my heart says I have unfinished business there, my head says that I have neither the financial resources nor sufficient sailing years left to open that can of worms.
     
  9. Skyak
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    Skyak Senior Member

    My cheap performance comment is based more on handicap values than experience and the idea is to eliminate 'tuning' for the purpose of attracting a bigger audience. Look at the wings on the AC boats -they have simple unambiguous adjustments for angle of attack, camber (depth), and twist -that's the way a sail should be! Did you see the AC 45s capsize? They had so much control of the wing they just flew them upright!

    You may be right about costs but I contend the thesis is untested. I am thinking there should be a 'manufacturers cup' That simply restricts the cost of the boat like they do with horses -the winner or any contestant can be purchased at the class value. If you can win the $10k class with a winged cat that cost $5k to build, you are in business!
     
  10. CT 249
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    CT 249 Senior Member

    I don't think that gggGuest is wrong about costs from the information I have heard from boat owners and users. His thesis is certainly not untested, it it tested every day by those who race development classes and have to buy and maintain things like Int 14 foils, carbon A Class hulls, etc...people like gggGuest himself, in fact.

    Experienced and successful home builders (and I'm talking about people like a guy who won a world A Class champs in a home-built boat) have found that creating things like effective hydrofoils to be basically impractical and almost impossible. And everyone I have ever discussed wingsail design with says that there is nothing simple about creating effective ones. As gggGuest says, these are not simple options.

    Windsurfers have so much control over their rigs that they fly them upright like an AC45, and drag the sailor upright too. Yet such rigs are in many ways inferior to conventional rigs in terms of adjustment and like wingsails, they don't seem to provide the correct lift/drag/centre of effort characteristics for most boats. As Frank Bethwaite found after years of experiment, the conventional rig is surprisingly efficient and effective. Something like adjusting mast bend can be incredibly simple (just use chocks or stays) so it's hard to see why you believe it to be inherently more complicated than something like a wing.

    The problem with cost limit classes would surely be that the fastest boat for the buck would be nasty in many ways. It would be rough to look at, because a good fairing and paint job would be too expensive. It would be difficult to use because nice roller-bearing blocks would be too expensive. It would be very difficult to sail, because there would be no limit on beam and therefore you would combine the maximum righting moment with minimum beam and a heavy rig. Convenient things like comfortable padded gunwale footloops would be replaced by painful old-fashioned rope loops.

    Would it be a good thing if one could somehow win the $10k class with a winged cat that can only be sailed by the very best and fittest, is made of 2mm interior plywood and must be carried to the water by a team and falls apart at the end of each regatta? No one else would have a chance and yet the boat would be nasty to sail.

    The restrictions used by popular development classes like the A Class, 16 and 12 Foot Skiff, Merlin Rocket, NS14, Cherub, Raceboard, etc are not created by ignorant stick-in-the-muds, they are created by people who actually have hands-on experience in the issues. While I'm not saying they are perfect (as a member of the international technical advisory committee for one of the above I tried to loosen the restrictions) they are normally the result of actual trial and error experience and practical necessities, rather than conservatism. The people in such classes don't create rules and extra cost just for fun; for example the 12 Foot Skiff guys have made their tubular transom trapezing extensions of out old broken carbon fishing rods but the boats still cost a huge amount and therefore they have restrictions on foiling to make them somewhat affordable.

    I recently bumped into a guy who had spent years committed to high performance sailing in an area where it was uncommon. He had moved from a fast skiff type into the least restricted of all skiffs, and them he had moved to a slow boat. Why? Because while he appreciated the high performance boat, he was sick of spending 90 minutes rigging, 90 minutes unrigging, and 90 minutes repairing or maintaining for every 60 minutes sailing. He was also sick of having to drive hundreds of miles to find like-minded sailors.

    That class lost a bunch of club fleets when it adopted pre-bent masts without halyards, because that meant the boats had to be rolled over to be rigged and that was impossible to do on a crowded pontoon or jetty. Issues like that really hurt a class.

    There's been no great discouragement of technology in sailing. It's just that the classes that encouraged technology too much are either dead or tiny, and the vast majority of people prefer classes that limit technology because it can create boats that are too expensive and difficult. Many of the classes I love best have few rules, but the downsides of that approach have to be recognised.
     
  11. gggGuest
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    gggGuest ...

    Good grief. Highly admirable as the wing sails are, those things are the most horrendous proposition to build own and sail with! The complexity of construction, the works and controls inside them, the maintenance, the nightmare of rigging and storage... Read up what the C class boys have to say!
     
  12. milessmiles
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    milessmiles Junior Member

    Hi, why hang the tapeeze wire from the mast,why not from the centreboard box. Would that not alleviate upsetting rig tension
     

  13. El_Guero

    El_Guero Previous Member

    Wouldn't trampolines give you much of the same benefit? Without the added need of being hooked up? Or, you could hook up as well, there would be added safety.
     
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