sail aerodynamics

Discussion in 'Hydrodynamics and Aerodynamics' started by Guest, Mar 21, 2002.

  1. Mikko Brummer
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    Mikko Brummer Senior Member

    Totally agree, the the lack of gust response is the problem with a wing mast... but the gust response of the unstayed Finn mast is best of them all, bending both fore aft (more) and sideways (mostly in the top). It allows one man without any hiking aids (but the straps) handle the relatively narrow boat with a 10,8 sqm sail from 0 to 35 kn of wind. Without the bendy mast, the Finn could not be sailed in winds over 15 kn.
     
  2. CT249
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    CT249 Senior Member

    WARNING - THREAD DIVERSION!!!!!

    No, Brian, those remarks weren't directed at you. It was directed at people like some on BDF who have made wild claims, such as that rotating masts reduce drag by 30% (or something similar), or that rotating masts are not common just because "conservative rule makers" require stays (which is simply not true).

    However, at the risk of a diversion, I have to say that the mere fact that SOME rating rules outlaw SOME ideas is quite clearly NOT evidence of conservatism. There are many reasons to introduce restrictions into classes, and many of the most innovative designers have created restrictions of their own.

    To take the example you gave, there are several reasons why Francis' rig could have been barred from the R Class that have nothing to do with being conservative. It was apparently very expensive, so if it was widely copied, the R Class would have become the exclusive preserve of an even smaller number of even richer men. Surely you are not going to claim that trying to keep costs down is "conservative", are you?

    Nat Herreshoff, the man who designed the Universal Rule that governed the R Class, did so because he wanted boats to be heavier and more "wholesome" than the radical scow-like shapes of yachts like Reliance. Was that an example of blind conservatism, or was Nat a brilliant, clear-thinking and logical man who realised that the sport would be best served by cheaper and more usable boats?

    Nat Herreshoff warned Francis that his rotating mast and aerofoil forestay would cause trouble with hoisting sails, were not rated fairly under the rule that Nat himself designed and would be banned! Those who banned Francis' foils can therefore easily be seen to be doing just what the rules architect (one of the greatest ever designers) thought would be fair and reasonable, rather than being dismissed as "conservatives". Or are you classing Nat as a conservative too?

    So there is simply no evidence that I can find (and I have read lots of Francis' and Nat's letter about the boat) to show that the ban on the rotating mast and aerofoil stay was caused by conservatism. The Live Yankee rig seems to have been very costly and troublesome in the short period it was in one piece - NOT a good thing for a class to encourage. Banning it can be seen as perfectly reasonable.

    As noted, many of the most innovative designers (including Jack Holt, John Spencer, Uffa Fox, Nat Herreshoff) and Francis Herreshoff himself were in favour of restrictions on designs*. They were clearly not all arch conservatives, so they show that simply equating rules with conservatism (as is often done) is wrong. Sure, sometimes rulemakers are ruled by conservatism - but surely in the name of logic we can't say that any particular rule was generated by conservatism, unless there is good evidence!


    *Francis himself wanted rules to ban genoas and parachute spinnakers, because he did not think they were worth the cost and hassle. He approved of the ban on bulb keels in one of his favourite classes because they caused launching problems. If it was OK for him to want to ban things on such grounds, why were the R Class rulemakers labelled "conservatives" when they banned his rig?
     
  3. brian eiland
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    brian eiland Senior Member

    Perhaps I should have separated those two thoughts into two different postings. I was not necessarily linking those 2 items, 'conservative sailing community', and 'rating rules enforcement' so closely as you have suggested in your posting. In fact here is what I posted.
    .

    I am saying BOTH of these factors, separately and together, have acted to suppress innovation in the sport of sailing, and certainly more in the bygone days, than more modern times.

    Example of rating rule 'interference' I have submitted:
    I believe that the 'multihull movement' really sparked some major changes/perceptions in the sailing fraternity, and brought about a lot of 'out-of-the-box' thinking in the sailing market. Had that 'multihull movement' NOT occurred, I believe a lot of the innovative spirit we see in the market today would be much more subdued by a 'tradition' approach.

    BTW, I didn't 'label' the R-class rulemakers as conservatives, nor did Herreshoff in his memoirs. He simply said "they promptly passed the rule prohibiting revolving masts, double luffed sails, and similar contrivances"

    So racing rules AND conservatism have BOTH acted to slow down the innovative art of sailing design.
     
  4. brian eiland
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    brian eiland Senior Member

    From my website, posted back in 2000 (but the thoughts on this site originated long before this)


    http://www.runningtideyachts.com/multihull/
     
  5. CT249
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    CT249 Senior Member

    If you don't think the banning of Francis' rig was conservative then why did you include it as an example of a ban in a thread decrying conservatism, just after you mentioned rating rules that banned new ideas?

    It seems from the quotes that you think I'm against new ideas per se. That is certainly not true - I'd like to shake the whole sailing scene up in a far more dramatic way than you do, I think. My point was that we can't just look at an idea that has been rejected and say it was rejected because of a "conservative sailing community". If we examine the reasons things were rejected we often find that they were rejected for good reason.

    If we go down this track further, we'll just derail the thread more. But to give one counterpoint to your posts, let's look at your first examples. Cascade was not a breakthrough, but a very slow 37 footer that had the rating of a 30 footer and couldn't always beat them across the line. She was beaten on scratch by Scampi 30 in the half ton titles. Changing her rating was not conservatism, but a perfectly logical reaction to a fault in the rating rule that she illuminated. Or do you actually think that sailing would be better if boats like Ganbare, the first Farrs or the Santa Cruz 33 were replaced by much slower, heavier Cascade types that were entirely a creation of a fault in the rule?

    To take another example - the fully battened main was common in many classes many years before modern multis arrived. Most Downunder sailors for generations grew up with them. The reason we didn't (and don't) use them in all boats is not because of conservatism, but because they are not always better. There were also quite logical, practical and specific reasons why innovative sailors in England didn't like fully battened mains - it was NOT just because of conservatism.

    Those examples are issues where the true complexity of the issue is hidden when assume that conservatism is the issue. Sure, sometimes conservatism is at play, but time and time and time again there are actually good and logical reasons why some people don't take up certain ideas.

    To try to put the thread back on course, the same applies to wing masts (in my experience). They are great in some ways but problematic in others, and therefore those who say that their limited use is due to conservatism are ignoring the fact that they have very real drawbacks that mean they are NOT the logical choice for many craft, and they often don't perform as well as claimed.
     
  6. powerabout
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    powerabout Senior Member

    has anyone been able to get a rotating wing mast to work on a keel boat?
     
  7. Gary Baigent
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    Gary Baigent Senior Member

    Yes, the IMOCA 60s are a good example. As already said, Greg Elliott had wing masts on a number of his monohull designs dating from the mid to late 1980s - except they didn't rotate far enough to gain the full advantage of that type of rig - although they still worked well enough even with a step between mast profile and sail.
    Brian Eiland, all your points are very valid regarding conservatism; history shows that in most cases (but not all), radical but quite logical design improvements have been very much frowned upon and then outlawed by the establishment.
    CT can make and twist his arguments/comments to suggest this is not a fact but it is.
    Cascade was not radical, actually a slow hull but one able to carry a larger larger sail area by side stepping the rule and the sloops of the times.
    Taking his argument further, a Farr with high sail area double rig, with far better hydrodynamics and proportionately lighter hull, would also crush the opposition. It is what he did later with the two NZ Whitbread ketches - and cleaned up. And then the not conservative lightweight W6Os came along making the heavier maxis obsolete. And there was plenty of moaning on the bar from the conservatives when that occurred.
     
  8. CT249
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    CT249 Senior Member

    and GB can keep making incorrect comments that insult other people, without providing any evidence....


    On another note - it's funny in a way to see people here criticise things like the re-rating of Terrorist and Cascade, and Live Yankee. No one here was in the position of losing lots of hard-earned money by having their boat made obsolete in those classes. Essentially those who criticise "conservatives" are saying that OTHER people should lose enormous amounts of money by having to buy new boats. It's easy to spend other people's money while slinging mud from the sidelines.
     
  9. Gary Baigent
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    Gary Baigent Senior Member

    Your reply is not a reply and specious anyway.
    What is all this talk about expense because newer, different, superior designs make earlier models outmoded or extinct?
    That is the natural order of everything.
    Or do you exist in a one design world of fixed non-animation, locked in last year - oir last decade - or last half Century?
    Not that I'm against nostalgia or classic boats but if you're in a development class, then you have to live with developmentation.
    Expense has nothing to do with it. Sailors enter these classes with their eyes wide open.
     
  10. CT249
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    CT249 Senior Member

    Gary, despite your snarking you have not provided any evidence for your claims. You claim, for example, that those in a development class 'have to live with developments', but provide no evidence about the pace of change they have to live with, or the range of that change. Nor do you deal with the fact that all development classes that survive "live" with developments by banning some of them.

    I never claimed that conservatism does not exist, or that all rule changes are good. All I am saying is that there must be some evidence that conservatism was the relevant factor in any particular instance under discussion, such as whether wingmasts were adopted or not. Without that, discussions about development or change tend to simply become a simplistic case of development v conservatism.

    Even if sailors enter development classes with their eyes open, they can still be mislead or caught out by unpredictable changes. To give one concrete example, in the early '70s in NZ a leading designer (John Spencer) wrote that half tonners provided a good class for typical cruiser/racer owners to get involved. Woodruffe wrote the same shortly afterwards. Within about three years, the half ton class had become one in which designs became obsolete within a few months, and no cruiser/racer was competitive. Those who got into the class listening to good sources like Spencer and Woodruffe would have found their words to be hollow. They would have found their boats worthless for class racing. Try telling those guys that the loss of the money they worked hard to get is "nothing to do with it".......

    Were you there? Did you lose the chance to race competitively with a boat you may have slaved years to earn? If you have not been in that situation, how did you earn the right to sneer at those 'conservatives' who would like a class to stay close to its original ideals and aims?

    The "live with development" ethos has seen the death of the development 18 Foot Skiff, the death of the development 16 Foot Skiff, the near death of the once-popular development R Class, and the death or near-death of many other development classes from boards to maxis, including some I loved and raced in with success. And no, I don't live in last century - I live in this century, when many one design classes are doing very well, when they are full with hundreds or dozens of bright-eyed and happy sailors enjoying themselves each weekend - and when sadly many wonderful development classes have been all but destroyed by those who don't care for practical matters such as protecting the existing fleet and owners.

    By the way, when did you last race at national level in a development class? In other words, when did you last practise what you preach? Or do you just throw **** from the sidelines?

    Development is great. The contempt that you and others show for other sailors is not.
     
  11. powerabout
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    powerabout Senior Member

    I think IRC does a good job of handicapping out or banning things are are not in the interest of the consumer boat buyer/racer/operator
    And we have development classes and one off records for anyone that wants to go down that route and owner driven classes that make their own rules.
    Canting keels anyone?
     
  12. brian eiland
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    brian eiland Senior Member

    Specifically why I chose to stay out of the 'racer/cruiser' mode....
    I was excited (and still am) with new innovations, ...damn the traditionalist.
     
  13. brian eiland
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    brian eiland Senior Member

    BTW I just remembered another 'event' that occurred near that time I was getting involved with the idea of designing sailboats,....the emergence of the Morgan Out Island vessels.

    Wow, did that event set the sailing world back a little. A pure cruising design, as opposed to all of the 'racer-cruisers' at that time.
     
  14. brian eiland
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    brian eiland Senior Member

    Full Batten Mains

    Perhaps we just didn't get the news over here in the USA about this prolific use of full batten mains at such an early stage,....I just don't recall it??

    Perhaps you can point out this 'common use' in the early days before multihulls??
     

  15. Petros
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    Petros Senior Member

    One example: most of the boats in the orient had full battens for many centuries, not just the junk rigs. they were very efficient rigs compared to the square riggers used in Europe at the time.

    I think perhaps Australia and NZ sailor have been more influenced by these far east rigs than, along with European influence of the colonists, long before these concepts were "discovered" by European or North American ship builders. I suspect this is why multi-hulls are far more common in marinas down under than in America or Europe.
     
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