Groupama bites the dust-TJV DISASTER continues!

Discussion in 'Sailboats' started by Doug Lord, Nov 10, 2005.

  1. D'ARTOIS
    Joined: Nov 2004
    Posts: 1,068
    Likes: 18, Points: 0, Legacy Rep: 321
    Location: The Netherlands

    D'ARTOIS Senior Member

    I believe that the whole turbulence has nothing to do with design, or that tri's or cat's are less seaworthy than mono's - as long as you know how to sail and handle them.

    The fact is that those boats are driven beyond there limits. Beyond their design strength. It is similar to F1 racing - you may drive a car against its borders, or you go over it and crash! Simple comme bonjour!

    The French belong to the best multihull sailors but once they step on board they loose very quickly of all that is reasonable, secondly, their sponsors expect that from them.
    Racing is taking your risk, and don't complain when it goes wrong!
    That's all I can say.
     
  2. Doug Lord

    Doug Lord Guest

    water ballast on multihulls

    Heres a thread on the boatdesign forum by that name:
    http://boatdesign.net/forums/showthread.php?t=6504&page=2
    Van Norstrum, it's not that water ballast can't be used on multies it's your description of what happens when it is that needs help..
    Water ballast has been used on many multies and ,I think, even on the ORMA 60's except that I'm fairly sure it is allowed only in the main hull on those boats. I'm sure I remember reading about one of the 60's using water ballast to enhance pitch resistance as well as RM.
    Water ballast is allowed under the Lake Eyrie Multihull/GLMRA PHRF Class Rule,and under the FICO safety rule for multihuls(at least thru 2003);see: http://www.fico-sailing.org/pages_uk/reglement.htm
    It was used on the Gougeon 32 cat:
    http://www.southwindssailing.com/articles/0102/goug0102.html
     
  3. Skippy
    Joined: Nov 2004
    Posts: 568
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: cornfields

    Skippy Senior Member

    yokebutt: [good advice]
    Lorsail:
    Bad advice, Yoke.

    Van Nostrum: [politely worded opinion]
    Lorsail:
    "equalization of pressure"??? You definitely need help-why don't you start another topic on water ballast for multies and maybe you'll get it....

    Van Nostrum: [politely worded counter-arguments]
    Lorsail:
    Frank, I mean Van Norstrum, ...

    Doug, don't even think about trying to accuse someone else of being more Frankish than you. You criticized Yokebutt for giving perfectly good advice, and now you're ridiculing Van Nostrum for making reasonable statements in a civil way. Why don't you get a better attitude.

    Lorsail: Van Norstrum, ...
    Doug, thank you for rethinking that little jab at VN. I see you deleted the trollish part. That's a start.

    Van Nostrum: Am I correct that none of these trimarans made use of water ballast? if they equalised the forces using water ballast then these capsizes would not have occurred.
    Being able to fill compartments in the windward hull of a trimaran would allow for an equalisation of pressure across all cross beams rather than the complete weight being placed on the leeward hull and cross beams


    The force on the sail(s) tensions the windward shroud(s) and compresses the mast. If a trimaran is flying its main hull, then the leeward ama takes the combined downward force of the boat's weight and the wind's force on the rig. So the windward shroud is pulling up on the windward ama, the water is pushing up on the leeward ama, and the mast is pushing down on the main hull.

    This generates large stresses on the main hull and the beams where they join with the main hull. Windward ballast will tend to bring the boat back upright, reducing the rig's downforce and putting some weight back on the main hull. While the use of the word "pressure" may be inaccurate, and the idea may or may not be correct, I think VN is trying to make a valid point that I would like to see a serious response to.

    As for the general question of what to do, Tom has recommended reefing as the best solution.
     
  4. Doug Lord

    Doug Lord Guest

    attitude

    Geez, Skippy I thought that advice thing had been straightened out in the other thread-and I thought I had -and have a great attitude. That's two cases where you have been wrong!
    Oh, I mean two cases where after it was explained clearly you were proved to have an incorrect assesment of the rather perplexing complexities of a subtle situation..
    Something like that anyway.....
     
  5. usa2
    Joined: Jan 2005
    Posts: 538
    Likes: 1, Points: 0, Legacy Rep: 11
    Location: Maine

    usa2 Senior Member

    it seems maybe VN was just using the wrong terms Doug. It doesnt mean you need to have a go at him.
     
  6. cyclops
    Joined: Feb 2005
    Posts: 1,059
    Likes: 5, Points: 0, Legacy Rep: 38
    Location: usa

    cyclops Senior Member

    After reading all of the opinions. The truth is simple and pridictable. ALL multi hulls are called that, but are really raced on a tiny sponson or only 1 hull. They are racing mono hulls. To classify them as multi hulls is to call all of us stupid jerks. -------------------They are getting exactly what they want. Don't worry about them. They are doing want they want. Most of you scream " too much government interference". Now you are unsure? Make up your mind. You people do not have any strong commitments. It changes with each race.
     
  7. Van Nostrum
    Joined: Nov 2005
    Posts: 39
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: next door to Doug

    Van Nostrum Junior Member

    thankyou skippy :D
     
  8. Doug Lord

    Doug Lord Guest

    Power to carry sail

    Skippy said:" Windward ballast will tend to bring the boat back upright, reducing the rig's downforce and putting some weight back on the main hull. While the use of the word "pressure" may be inaccurate, and the idea may or may not be correct, I think VN is trying to make a valid point that I would like to see a serious response to."
    Bad advice ,Skippy! UhOh, ah, you're not giving advice ,right? So I'll rephrase it: When any form of ballast is added to the windward side of a multihull it increases power to carry sail and therefore the compressive loads on the mast in a stayed rig. You cannot add ballast to the windward side of any multihull with a stayed rig and not INCREASE the compressive load on the mast! Which ,of course adds more load to the entire structure of the boat.
    The solution here may be to find a way to enhance controllability with increased power to carry sail:
    Most of the ORMA 60's are designed to sail with curved daggerboards in each ama the purpose of which is to reduce the displacement of the ama when flying the main hull. At some point because the hydrofoil system has no altitude control it is possible for the ama to fly so high that it is entirely out of the water drastically increasing the chance of foil ventilation and a catastrophic crash. In those conditions some water ballast in the main hull might help by preventing that from happening.
    But what I think would help more than anything would be to keep the boat light and use a rudder t-foil and a mainfoil on the center daggerboard. The ama foils would still be used. The mainfoil would have ,perhaps,a wand for altitude control though an angle sensor of some sort might work well controlling a flap on the main foil.
    This would greatly enhance the pitch stability of the boat and automatically control the angle of heel since the mainfoil would pull down at some point.(It might also fly the main hull sooner) Then if the ama foil ventilated the boat might be less likely to pitchpole.
    Some of the 60's have the ama foil and that's it-- that allows the thing to be very unstable in pitch the more the ama foil lifts. A couple of the boats have the ama foil and a rudder t-foil but they can easily fly the main hull so high that the rudder t-foil comes out of the water. But even if the rudder foil works the boat can be diagonally unstable on an axis of rotation between the ama foil and rudder t-foil.
    I'm fairly confident that an altitude controlled mainfoil would eliminate those problems . The downside is that the mainfoil would always be there and would be a source of drag in lite air. Now , if a way could be found to retract such a foil it might really be a good solution...
     
  9. Skippy
    Joined: Nov 2004
    Posts: 568
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: cornfields

    Skippy Senior Member

    Skippy: Windward ballast will tend to bring the boat back upright, reducing the rig's downforce and putting some weight back on the main hull. While the use of the word "pressure" may be inaccurate, and the idea may or may not be correct, I think VN is trying to make a valid point that I would like to see a serious response to.

    Lorsail: Bad advice ,Skippy! UhOh, ah, you're not giving advice ,right?
    No, I was not giving advice Doug. So maybe you could delete your inappropriate comments instead of posting them as though they were warranted.

    Lorsail: When any form of ballast is added to the windward side of a multihull it increases power to carry sail and therefore the compressive loads on the mast in a stayed rig.
    You cannot add ballast to the windward side of any multihull with a stayed rig and not INCREASE the compressive load on the mast! Which ,of course adds more load to the entire structure of the boat.


    Doug, that whole statment is based on a false assumption, just like the one where you used the 100% rudder-area rule in the other thread, which was a modification instead of a new design. Both of those claims do nothing but confuse the discussion, becaue they don't address the actual problem at hand.

    The assumption that the boat's "power to carry sail" will determine the stresses on it at a given speed is incorrect if that power is not required. The sail on a ballasted boat heeled at 5-10 degrees requires LESS athwartship force to generate a given amount of propulsion than an unballasted one flying the main hull, heeled at 20 degrees or so. The weight of the ballast is at least partially offset by the reduced downward component of the sail's force, and the sail will have to be sheeted out a little. The more favorable sail angle could possibly allow lower mast compression at the same speed. It's definately not something you can just write off in a sentence or two.

    But Doug, that's not even the point of my post that you're responding to. As I believe I made clear, VN was referring to bending loads on the beam joints on the main hull. As long as the main hull is in the water taking displacement, those stresses will be reduced. In the extreme case of the leeward ama displacing just enough water to support its own weight, those bending stresses will be very small.

    Lorsail: The solution here may be to find a way to enhance controllability with increased power to carry sail:

    So if it's not too much trouble for you Doug, the solution is for you to stop criticizing people for expressing reasonable ideas, and to answer what people actually say in their posts, instead of confusing the issue by talking about something else. That applies whether those ideas turn out to be correct or not.
     
  10. usa2
    Joined: Jan 2005
    Posts: 538
    Likes: 1, Points: 0, Legacy Rep: 11
    Location: Maine

    usa2 Senior Member

    I think what would help most would be for these types of boats to avoid those conditions. Hydrofoils wouldnt help at all because the waves would still be there.
     
  11. Van Nostrum
    Joined: Nov 2005
    Posts: 39
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: next door to Doug

    Van Nostrum Junior Member

    Doug the solution to your pitching problems due to excessive lift is to reduce the amount of lift... now you could build some crazy *** contraption like you've dreamt up, or you could just pull up the main foil thereby reducing the amount of lift, as the boat would be in strong breeze/moving quickly there would be minimal loss due to leeway, however then you couldn't carry as much sail (or you'd need to build larger floats), so we're back to pumping water into the windward hull to reduce the "pressure" (call it whatever you want, maybe load is more accurate?), because these boats can cant their rigs you could even reduce the loads across the whole boat.

    Why do you bother asking for opinions when you don't want to hear them?
     
  12. sharpii2
    Joined: May 2004
    Posts: 2,246
    Likes: 329, Points: 83, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member


    As Dick Newick always said: "The price of speed is accidents."
     
  13. cyclops
    Joined: Feb 2005
    Posts: 1,059
    Likes: 5, Points: 0, Legacy Rep: 38
    Location: usa

    cyclops Senior Member

    Please realize, these racers have the the mind set of, "The other boat is going to have trouble, not me." They have lied to themselves for so long, they believe the lie.
     
  14. Doug Lord

    Doug Lord Guest

    Preposterous!!!

    That is so absolutely absurd I can't believe you would say something like that! These sailors are professional, expert,well prepared and completely knowledgeable about what they are doing!
    I don't know the solution for sure but besmirching the sailors is ridiculous, unfair and really low!
     

  15. Van Nostrum
    Joined: Nov 2005
    Posts: 39
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: next door to Doug

    Van Nostrum Junior Member

    Just thought I would highlight this, next time you ask for an opinion, please think about that, if you don't know then LISTEN to what others have to say!
     
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.