Multihull Capsize Prevention <split>

Discussion in 'Multihulls' started by MikeJohns, Jun 23, 2011.

  1. CatBuilder

    CatBuilder Previous Member

    I'm sorry, I have no information on trimarans. I never investigated the data on them.

    I'm not saying the power cats are capsize proof, just that that the chances are so slim, it has never happened.
     
  2. CatBuilder

    CatBuilder Previous Member

    I did mention this somewhere... :)
     
  3. HASYB
    Joined: Jun 2011
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    HASYB Senior Member

    Hmmmm,

    Very informative thread!
    Hope to learn more like what can be done to avoid or survive in multihull threatening situations

    A little more information on troubled multihulls here;Click on: Que sont ils devenu? http://www.goldenoldies.biz/

    And since Albert was brought up:
    "In theory, theory and practice are the same. In practice, they are not"
    Albert Einstein.

    Cheers,
     
  4. CatBuilder

    CatBuilder Previous Member

    Out of context?

    That only proves you never read the link to Richard's website I provided in this thread. The quotes are from a series of pages he published dedicated to discussing catamaran stability.

    You would know that (and could have referenced the stability curves in the article) if you bothered to read what Richard published, instead of ignoring it.

    Richard does a lot of sailing. He isn't at a desk all day, so he is on forums here and there. I'm sure if this thread doesn't get buried too far back, he will have a comment.

    For now, why don't you educate yourself by clicking on the link and actually reading?
     
  5. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    Your second point is correct, not all the information is recorded. However how much is how much is needed? (How easy is it to record everything in such circumstances too?) Does the name influence the recorded event of the capsize, would knowing the name make the capsize not occur?...or will it make your reading of the event different? If the former, hmmm...I'll let you mull over that one, if it is the latter, then it changes from a fact to an opinion you have subjectively formed, for whatever reasons. Which must be defined for anyone to accept it as a worthy opinion.

    On your first point, either one accepts that boat XXX (as recorded in that list) capsized from a breaking wave, of one does not. That is for you to reconcile with your perception of what is a fact or an opinion subverted as a fact (or an incomplete fact as you infer) and if you have any problems with that, then you should take it up with the author(s) of the report.

    Thus, did the boat capsize, yes or no? It is not a "kind of fact"...it is a binary fact.
     
  6. CatBuilder

    CatBuilder Previous Member

    Well,, that would be a fantastic record (one capsize in 40 years) if we could accept the capsize (with sails up) of this 30 foot cat in the pacific in1972 as wave induced. Is that really the best you could come up with?
    However, since the boat's beam is not included, we can't be sure this isn't one of those 1970's narrow beam cats that were unsafe due to improper l/b ratios.

    Catamarans frequently capsized 40 years ago.
     
  7. Gary Baigent
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    Gary Baigent Senior Member

    You miss my point entirely, Ad Hoc, a common occurrence it seems with you; I'm not disputing multihulls capsize, what I'm saying is that dumb seamanship causes most of them to go over. And narrow beamed boats have a reputation for that - and also large headsails, small main rig configurations, a carryover from unenlightened monohull rigs of the day, also was the reason for those early capsizes.
    More interesting and informative and far more extensive is Hasyb's posting of the Golden Oldies history, where in one large section of their excellent site, the names of all the boats are listed (so you can check the differing marine architecture, quite useful) and where they were damaged or abandoned and the reason for their demise. Interestingly, a very, very large number were lost at moorings during cyclones.
    And more positively there also is a list of those that have been restored and brought to life again; an advantage multihulls have compared to monos because if damaged, they don't go to the bottom faster than a stone.
     
  8. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    This is where you're getting very confused by your desire to overstretch a point of which I am unsure what it really is to be honest.

    I am making no claims at all, never have. I am simply presenting reports of evidence that was asked for. The whole report (which is over 18MB thus cant post) has more than 1 which you claim is required to satisfy you, yet you're suddenly unsatisfied when more than 1 is presented?.

    You requested at least one...the page from the report posted has 3. The whole report has more.

    You appear to have made up you own mind, fine, I personally don't give two hoots what you have concluded. Other than your assertion that such an event does not occur, where it has been demonstrated in the report that it does. You seem to have a problem accepting this for some reason??

    And how do you come to this conclusion from the report, can you please provide the evidence, with all the facts supporting this conclusion, as you rightly pointed out yourself, you require.
     
  9. MikeJohns
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    MikeJohns Senior Member

    Now you are posting from complete ignorance. You are not reasoning, you are make up facts to support a viewpoint. That’s not logical it’s just diatribe based on your feelings. If you want to be a sensible and safe operator of a catamaran it might pay to be a little less prone to these sorts of lines of reasoning .

    No it's a matter of courtesy. If Richard wants to discuss this he can. It's not up to you to declare that his position is inflexible. Every naval architect obtains the information on vessel stability from the same source, from the research establishments, information is shared discussed and modified through papers meetings and follow up testing and observation. It’s not a mystical intuitive process.

    The quote you are putting emphasis on is a statement by him that to his knowledge he knows of no sailing cat inverted under bare poles.

    So lets look at that in more detail since that may be the case but it needs to be better defined with some statistics.
    For example significantly: How many of the cats under bare poles in heavy weather in waves large enough to capsize or pitch pole them were lying to a sea anchor or a drogue?

    How many people would try and run off in a Catamarn in heavy weather without at least a small headsail ?

    Do you see the problem yet?

    Unless you separate out the reasons and the facts you can extrapolate facts incorrectly and jump to a grand fallacy.

    No Naval Architect including Richard would sensibly claim that no cat has never been inverted by breaking waves. So already you appear to have taken his writing out of context.
     
  10. MikeJohns
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    MikeJohns Senior Member

    That's a very unhelpful generalisation. Notably it crops up often as some sort of trade off for the total loss of a multihull vessel at sea following capsize. It's very easy to design a monohull that won't do this.
     
  11. redreuben
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    redreuben redreuben

    Final siren is due on this thread I think.
     
  12. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    From this chart posted by Mike Johns, why would trimarans be susceptible to broaching, but not catamarans?
     

    Attached Files:

  13. CatBuilder

    CatBuilder Previous Member

    Not really. I'll bow out. No point trying to explain what seamanship is to desk jockeys. Not worth the electricity it takes to do so.

    As they say in the off topic threads, "can't fix uneducated.". Ok, I doctored that up a little. :)

    The overwhelming majority here agree with me, Richard, Gary, Silver Raven and Old Sailor.

    Carry on.
     
  14. Boat Design Net Moderator
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    Boat Design Net Moderator Moderator

    It's inevitable that members will sometimes strongly disagree with eachother, but let's please try to respect other members and keep things polite. Thanks.
     

  15. HASYB
    Joined: Jun 2011
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    HASYB Senior Member

    I guess designed/designing boats, with all the characteristics, and seamanship are condemned to each other. Apparently also people discussing above.
    Also I like to see each unlucky event on its own. There are just to many variables, circumstances and differences to generalize.
    At school I learned that a shipping disaster is an event at sea upon one can learn.

    Cheers,

    Hielan
     
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