Open 60 & 50 (IOMCA) rule should be changed

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

  1. bobothehobo
    Joined: Nov 2004
    Posts: 63
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Newport

    bobothehobo Junior Member

    MoB,

    The boat (Margaret Anna) had not been tested since the 2002 Rhute du Rhum (which it failed, but was allowed to sail out of class-then collided with a ship just miles from the start).

    Tim ran short on time and budget to get her tested here in the states prior to the Velux and I guess was just hoping the boat would somehow pass in Bilboa. He bet wrong, the boat's positive righting moment came in at 124.1, well short. This would have required either:
    a) adding 300 kg to the bulb, whilst the condition of the keel foil is somewhat unknown, and the designers of course don't want to sign off on it.

    b) replace stainless rod rigging with aramid rigging. Would have got him very close. Very Expensive (approx 100k) and just not enough time at that point.
     
  2. DGreenwood
    Joined: Aug 2004
    Posts: 714
    Likes: 34, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    I was there and involved in the measurement of that boat and 2 others. I won't comment on the Tims approach. I will, however clarify the measurement issue.

    First, the boat had not been tested and passed the required inversion test. This involves an expensive removal of much gear and turning the boat over to prove self righting. As Bobo pointed out, no canters have failed it and Petite Navire would not either, none the less, it must prove it.

    Second, the boat was more than 3 degrees from passing the AVS test. 3 degrees is actually quite a margin. The designer calculated a correction to look something like 300 kilos centered about 3.5 meters below water line.(if I remember correctly). This would put the keel structure in jeopardy and would involve some risk. This same problem could be corrected by updating the rigging to modern standing rig materials from the solid stainless wire she sports currently. Another expensive undertaking but a much safer and faster approach than adding more weight.

    Pretesting could be undertaken by the ordinary Joe if he had the help of the designer and the help of someone who had done this before. Not really very expensive in the scheme of things.

    I cannot stress enough the importance of seeking pro help with this sort of undertaking right from the moment the idea enters your head. It is always assumed that professional help is going to be too expensive. Quite the opposite is true. It can save you hundreds of thousands and maybe your life.
     
  3. bobothehobo
    Joined: Nov 2004
    Posts: 63
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Newport

    bobothehobo Junior Member

    Too funny.

    MoB, if you haven't figured it out, dgreenwood and I were there togehter.

    Bobo
     
  4. Vega
    Joined: Apr 2005
    Posts: 1,606
    Likes: 26, Points: 58, Legacy Rep: 132
    Location: Portugal

    Vega Senior Member


    Yes, I agree.

    The stability and seaworthiness of these boats has been greatly improved along the years.

    Take a look at this “paper” written by Jean Marie 8 years ago after the Vendee Globe 96/97 and the capsizes that happened:

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

    Today Open60’s are much more seaworthy than the ones that capsized on the 96/97 race and include all safety suggestions he talks about in that paper. Some of the rules he talks about are now even more demanding than those he suggested at that time.

    As you can see, he his a Guy not only interested in winning races with fast boats, but a man that takes safety as a primary goal.

    See also this one, written in 2000 about the risks and dangers of canting keels.

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

    If you look at the stability curve of a modern open 60, it looks great, with a huge positive stability a small inverted stability and an AVS bigger than most of other ocean racers.

    I don’t understand what you guys see wrong on the development of the Open60 boats, besides an aesthetical dislike for large transom boats.

    http://www.youtube.com/watch?v=LZcwoQoNVak

    The AVS requirements have increased along the years and I believe that the development will continue towards bigger AVS and more seaworthy boats.

    But a bigger AVS doesn’t necessary mean a less beamy boat, they can opt for a larger bulb, if a beamier boat gives more sailing potential.
     

    Attached Files:

  5. DGreenwood
    Joined: Aug 2004
    Posts: 714
    Likes: 34, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    Certainly in my case I have absolutely nothing against the Open 60---aesthetically or otherwise. In fact I happen to think they are as exciting as boats get. As far as I know, so does bobo.
    I was only pointing out some of the reasons the boats are shaped like they are.
    It is not nearly so simple as one would think to design an exciting and successful rule.
     
  6. bobothehobo
    Joined: Nov 2004
    Posts: 63
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Newport

    bobothehobo Junior Member

    And I feel in the case of the 60 IMOCA has delivered. The popularity of the Vendee has increased dramatically over the last 3 iterations. The next one is going to be amazing, with 20 or so boats on the line, many of them of the most recent (PRBIII, Delta Dore, Temenos) generation. You also have exciting new races like the BWR coming on line. Very exciting indeed. They are the most exciting boats to me from a technical standpoint as the designers, sailors, boats and shore teams are all extremely well developed.
     
  7. Guillermo
    Joined: Mar 2005
    Posts: 3,644
    Likes: 185, Points: 63, Legacy Rep: 2247
    Location: Pontevedra, Spain

    Guillermo Ingeniero Naval

    Stephen,
    I finally made it here....! ;)

    I'm not sure we should harness class designing when for race purposes. Development comes from testing to the limits, and extreme races, be them of boats, cars, or whatever, produce technical innovations later brought to the benefit of mass markets. What we need to harness in boating is how and which of those innovations are spreaded and used around for recreational units. But that's another story.

    Maybe the only restriction we should consider is those racing classes not being allowed to use highly expensive rescuing resources financed by the tax payers, if things go wrong in the middle of nowhere. But this is, again, another story.

    I find Open 60 rules to be a pretty solid set of rules, with an strong emphasis about safety measurements. I think this is precisely because promotors were well aware of the kind of 'distorted' and risky designs, as well as the risky type of sailing, needed to be adopted in the pursuit of speed.

    Cheers.
     
  8. Vega
    Joined: Apr 2005
    Posts: 1,606
    Likes: 26, Points: 58, Legacy Rep: 132
    Location: Portugal

    Vega Senior Member

    It is said that there are more boats than available places for that race. I believe that we will have more than 20 boats on that race;)
     
  9. Vega
    Joined: Apr 2005
    Posts: 1,606
    Likes: 26, Points: 58, Legacy Rep: 132
    Location: Portugal

    Vega Senior Member

    There are some. The one produced in biggest numbers is the Cigale.
    The nicest thing about those boats is that they can cruise fast with only a 10º heel.
    They are fast too.
    Take a look at the post 395 of this thread:

    http://boatdesign.net/forums/showthread.php?t=11479&page=27
     
  10. DGreenwood
    Joined: Aug 2004
    Posts: 714
    Likes: 34, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    "It is said that there are more boats than available places for that race. I believe that we will have more than 20 boats on that race"

    The major difference will be that there will be few, if any, adventurers. Most of these boats will be recent generation, competative pro boats. The podium is within the reach of a much broader range of teams than ever before.

    The most interesting aspect of this race will be to see how well the top guys handle the extreme power of the latest generation boats. PRB, Delta Dore, Temenos, Juan Ks new boats and a host of others have so much power, the real test will be in applying it at the right time. This is a matter of experience on the skippers part. This is why the Barcelona World race is so important before the Vendee. Although double handed racing will definitely be the most brutal form of racing, it will give the skippers a shot at feeling out the gas pedal.
     
  11. Man Overboard
    Joined: Oct 2006
    Posts: 246
    Likes: 13, Points: 0, Legacy Rep: 129
    Location: Wisconsin

    Man Overboard Tom Fugate

    Vega
    Thanks for the link. I had skimmed through that post and took a quick look earlier this month; I have been looking closer at Finot designs lately. Another example of water ballast in cruising yachts is the Dashews Beowulf
    http://www.setsail.com/s_logs/dashew/dashew29.html
    Really there should be a separate post to discuss this, but it shows how an open class can lead to refinement and acceptance of new innovative ideas.

    In keeping with Stephens’s original question ‘Should the Open 60 & 50 (IMOCA) rule be changed’; after reading others opinions, I have begun to form an opinion myself. When I began studying naval architecture over 20 years ago, among the first books I read was Marchaj’s Seaworthiness: The forgotten Factor. It, along with his other books are some of my favorite, as he bases his arguments on scientific observation, fact, and real life scenarios that are explained and confirmed with scientific efidence. Those of you who are familiar with his work know how he slams the skimming dish as a fundamentally un-seaworthy vessel. Yet the open 60/50 class has shown that the skimming dish (within a racing context) can be made very seaworthy, when specific safety issues have been addressed. In many respects it seems that they are safer than most blue water cruisers, albeit certainly not as comfortable. The IMOCA is gaining respect world wide, any changes to rules should be considered with apprehension.
     
  12. Guillermo
    Joined: Mar 2005
    Posts: 3,644
    Likes: 185, Points: 63, Legacy Rep: 2247
    Location: Pontevedra, Spain

    Guillermo Ingeniero Naval

    I have bolded the phrase because of its interest. To not kidnap this thread discussing no focused matters here, would you please bring this to the seaworthiness thread, to discuss it there?
    Cheers.
     
  13. Vega
    Joined: Apr 2005
    Posts: 1,606
    Likes: 26, Points: 58, Legacy Rep: 132
    Location: Portugal

    Vega Senior Member

    Jean Marie Finot has put in his site a new paper about safety and seaworthiness of Open 60s. It is a very recent one (12/12/2006) and it proposes to apply instruments to measure stress and pounding on the boats during the Vendee Globe (he has been making these measurements on "his" boats).

    This would be a non coercive measure that would contribute to the global pool of information (shared information) that would permit a much better understanding of the efforts and a correct dimension of scantlings.

    Those measurements would be sent in real time. If the measured efforts on the boat were putting in jeopardy the boat’s integrity, a warning would be sent to the sailor to ease up with the boat.

    It is only in French. I will post the most significant part:

    "Dans un premier temps, nous nous faisons deux propositions non coercitives :

    Les engagés rendent publiques, avec leur architecte, les charges à partir desquelles le bateau est construit (pression d’eau sur la coque, charges sur le lest, fréquences, etc…) ainsi que les taux de sécurités envisagés entre la charge de travail et la charge de rupture. Parallèlement, la construction des échantillonnages, la mise en œuvre, les tests, les contrôles des pièces principales sont déposés dans une enveloppe qui reste fermée, mais qui est rendue publique s’il arrive un accident au bateau, de façon à ce que l’on trouve la raison et que de tels accidents ne se renouvellent pas.
    Cela permettrait que les expériences meilleures d’aujourd’hui servent à tous les navigateurs à venir et qu’il y ait davantage d’échanges sur ces points.


    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.
    Cela permettrait aussi de juger des échantillonnages optimum à respecter.
    Nous avons appareillé ainsi plusieurs de nos bateaux au cours du Vendée Globe 2000/2001, et nous sommes prêts à mettre en commun cette expérience,.
    En terme de coût, elle ne représente pas une surcharge énorme par rapport à l’ampleur des projets actuels."


    jean marie finot
     
  14. DGreenwood
    Joined: Aug 2004
    Posts: 714
    Likes: 34, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    Funny...Bobo and I just had a discussion on such a notion.
    It is becoming clear that in order to control the power of the rig to its optimum, load cells on the stays would allow an empirical look at when and how to apply all the power available on these newer boats.
    Also the canting keel loads are of interest as well as furtherstudy on slamming loads.
    I have a copy of a study that Finot (and others) did on slamming loads quite a few years ago. It may still be available on his site, if not I can dig it up for anybody that wants it.
     

  15. bobothehobo
    Joined: Nov 2004
    Posts: 63
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Newport

    bobothehobo Junior Member

    I think it is imperitive that the Open 60s (not to mention the V070's) are fitted with load cells to measure the loads on key structures (keel rams, ram to bulkhead attachment points, rig, etc...) so that designers get a better understanding of the loads rather than making WAGs as to what the loads are at these key points (particularily at keel ram attachment points as these are still quite unknown during severe loading, ie: when the boat makes contact with the water after falling off the back of a steep wave--MASSIVE dynamic loading there).

    Vega, what you are suggesting here would not be allowed under Vendee Globe rules, as well as most other IMOCA events (would probably be ok in the Route du Rhum). You could not have the load measurements sent to the engineers during the race, then have the engineers ring up the sailor and tell him to make changes to his operation of the boat. This would be considered outside assistance and would disqualify the sailor (same as having a weather router). If however, the designers plugged certain criteria into an onboard computer, connected said load cells to this onboard system and then that system gave warnings to the skipper all would be legal.

    Cheers,
    Bobo
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.