Open 60 & 50 (IOMCA) rule should be changed

Discussion in 'Stability' started by Stephen Ditmore, Dec 25, 2006.

  1. Vega
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    Vega Senior Member


    Yes, unless rules were changed in what regards safety information, but yes I agree with you.
    But it is no me that was suggesting that. I can have misinterpreted Finot, but what he says about that, on that paper is:

    « Equiper les bateaux d’un minimum de moyens de mesures sur les parties et les efforts essentiels.
    Ces mesures pourraient être lues en temps réel par les coureurs, stockées, et envoyées en temps réel. Le coureur pourrait ainsi juger du moment il faut lever le pied. »


    A translation:


    “The boats should have a minimum of equipment capable of measuring, on the right spots, the essential efforts.
    Those measures could be read in real time by the skippers, stocked, and sent in real time. The skipper could make an informed judgment about the boat and know when he needs to ease up.”


    Regards
     
  2. Man Overboard
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    Man Overboard Tom Fugate

    The following statement by Juan Kouyoumdjian may give a designers perspective. Such a rule seems to be in line with other rules that focus on safety, while alowing the design(and sailer) to be pushed to the limit.

    Yachting World:
    But surely when you're designing such a yacht you must have reservations about certain areas and whether these areas need 'beefing up' a bit to withstand the conditions?
    Juan Kouyoumdjian:
    "Yes, I do but I also know that if I do anything about it the boat is not going to win. There's a fundamental junction here in the limit of the designer and the responsibility of the crew. The point I'm trying to make is that the breakage of these boats at this level, and outside the Volvo as well, is very much in the hands of the crew because again you cannot design them not to break.
    Source: http://www.ybw.com/auto/newsdesk/20051020140348ywvolvo06.html
     
  3. Vega
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    Vega Senior Member

    The new Finot Plan "Generali" for Yann Elies, for the Vendee Globe.
     

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  4. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Vega:

    I was hoping for your feedback on this. Thanks for chiming in. But I'm going to take issue with you concerning the boats being "less fast" if you construct the rule so that it allows designers the freedom to find optimums for themselves on a more level playing field.

    If you set the constant such that most or all of he existing fleet would still be legal, the change could not possibly make boats slower. What it would do is decouple the allowed weight of water ballast from form stability. There is no need to reward form stability in a rule with very little restriction of sail area/displacement ratio. LET DESIGNERS FIND THE OPTIMUM! It's stability at high angles of heel that needs to be engineered into keelboats in a consistant way. If that weren't the case we'd remove the lead ballast altogether!

    In Class40, form stability and allowed weight of water ballast are not coupled, since the amount of water ballast allowed is fixed. Even though HM(movable) is a bit greater for beamy boats, the fact that the weight of the water ballast remains the same gives designs with more moderate beams a fighting chance. Not so under IMOCA.

    I mean to include HM(movable) from canting keels as well as water ballast. If in the end we disagree, so be it, but don't disagree with me on the basis that what I propose would make the boats slower when that couldn't possibly be true (if it is callibrated such that existing boats measure in). The effect would be to allow narrow boats to deploy more movable ballast than they are currently allowed to.

    Cheers,
    Stephen
     
  5. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Is that an acknowledgement that boats designed under my proposal might be faster?

    Which is exactly what I proposed in the post that began this thread. Seems to me a proposal that would likely make the class faster, more seaworthy, and more "open" to design variation & experimantation ought to be considered. Concerning the Volvo 70s, the fastest boat's beam exceeded the minimum, suggesting the rule was unnecessary.
     
  6. Vega
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    Vega Senior Member

    Stephen, I am not going to take any issue with you:) . What I do not agree with you is about the need to harness designers... to produce seaworthy boats. These boats are seaworthy and in my opinion on an Open class, “harnessing” designers is not the way to go.


    This is an Open rule and should be as Open as possible, being the only limitations the safety measures and restrictions that make these racing boats the safest ocean sailboats ever made. Stability at high angles is not provided only by that rule, but also by the need to comply with maximum AVS angles in different configurations.

    Almost all cruising boats have worse AVS figures than those required for these boats.

    I don’t see any problem with these boats, nor do I think they can be beamier and still comply with the AVS requirements. Old Open boats have a problem and they can not comply already with the new standards, regarding AVS.

    What you propose is a little bit what they are doing in the 40class and the new 9m class (regarding minimum RM requirements at 90º of heel). I don’t see any problem with that, but that would not make narrower boats faster. Even if they could take more water ballast, the extra weight for the same RM would make them slower.

    Even if these are already the safest boats around, I will bet that they will continue to improve seaworthiness and final stability. I would say that the next step would be a more demanding AVS with the boat in the worst configuration, regarding water ballast.
     
  7. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Vega:

    It's true that I may have exaggerated in some respects. I think you're correct that the other stability rules, regarding AVS etc., are excellent rules. But in combination with the 20 degree (10 deg each direction) rule, the effect will be to scissor all the boats into a particular corner. Imagine two lines on a graph, one with positive slope, the other with negative slope. All the boats will end up being designed at the intersection of the two lines, and all the money will be spent understanding how to build the boat that best exploits the rule, which is not necessarily the same thing as building a better boat. That's my objection. All the R&D, on and off the water, would be better directed if the rule were simple and rational as opposed to a framework in which each element is necessary to compensate for flaws in the others. A nice smooth curve on a graph rather than multiple intersecting lines. Then, if wide is the right answer, so be it. Whatever the result, it will be a meaningful result, which is the beauty of a well conceived development class rule.

    I'll read more about the 9m. Sounds interesting. :)
     
  8. xarax

    xarax Previous Member

    Could you please, Vega ,explain this a little more? It seems to me that the boats are getting beamier, to a point where it would be unavoidable to clash with "aesthetic" considerations. A "normal" sailing boat is not meant to look like a sailing flying saucer...:) A reasonable restriction of beam max. to, say, 20 feet would n t spoil the spirit of the class too much, would it?
     
  9. Stephen Ditmore
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    Stephen Ditmore Senior Member

    But instead of establishing a limit, why not fix the aspect of the rule that's driving the designs in this direction?
     
  10. xarax

    xarax Previous Member

    Dear Mr.Ditmore,
    I have seen all these videos with the boats trying to upright themselves, and I have to admit that the whole process is not very convincing to me...In real life situations, with all the ropes and spars and sail pieces and a probably broken rig who knows where, will these boats going to self-right themselves ? I hope so... I think that the situation is not described completely by the RM considerations, and that the movement of the hull at 90 degrees, due to loads of the destroyed rig, wave motion and other factors as well, is totally different than at 10. So I am afraid that even the change you are proposing, which is simple and completely correct from a logical point of view (one might wonder why it was not adopted in the first place), even this change will not be enough, I am afraid. I may well be mistaken in this, of course, and I very much hope I am. My idea was to combine a little more safety with a little less "abnormal" aesthetics, since the aesthetics of the "sailing flying disk" I was talking about is questionable, if not ugly. Is it not a fact of life that the aesthetics of our ship give us a great deal of pleasure, and may be it is for us as important for our well being as safety? A 20 ft beam limit is more reasonable, I suppose, than a, say, 30 ft. Your proposition could also be applicable in 20 ft, and I believe it should be indeed.
     
  11. Vega
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    Vega Senior Member

    and Xarax:

    Well, from my point of view the rule points to the right direction and that is: Faster boats that have to comply with a set of very strict safety requirements.

    The safety requirements are the important thing in what regards safety. They have been increasing in number and quality. The vast majority of traditional racing boats would be excluded by these requirements. You can always set a higher limit on safety requirements and that is what has happened in the last years.

    But, if you comply with the requirements, the shape of the hull should be dictated only by efficiency demands and that’s what happens in the Open Class and it gives the shape of the actual boats. I don't believe that if the boats were significantly beamier, they would not comply with the min (normal) AVS neither with the minimum AVS with everything in the wrong place (Keel and Water ballast).
     
  12. lazeyjack

    lazeyjack Guest

    Paulo, can you point me to the Gigales, cant seem to find them
    Cheers
    Stu
     
  13. Vega
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    Vega Senior Member

    With pleasure, this is one of the two boats that I would like to own. The other one is a narrow boat, the Luffe 43ds:p

    http://www.finot.com/general/index_ang.htm

    On the Index look under : "30 000 boats produced in the world" and click on Cigale 14 and Cigale 18.

    The manufacturer is Alubat, the same shipyard that build the OVNIs:

    http://www.alubat.com/

    Take a look at "Gammes"

    an "English" site:

    http://www.northseamaritime.com/Page/ALUOvni.htm

    Best photos:

    http://www.seilsamvirket.net/3_baat/Galleri_sveising og bygging/index.html

    http://www.seilsamvirket.net/3_baat/Galleri_dekk_interior/index.html

    Probably a good deal:

    http://www.yachtworld.com/core/list...00&luom=126&man=cigale&slim=quick&searchtype=
     

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  14. lazeyjack

    lazeyjack Guest

    oh I looked hard at the Ovnis, but they pound , like mad so we ended up with this I wont show the keel cos its top secret:))
    i,m looking forwards to this simple build
     

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