cheeky rafiki

Discussion in 'Stability' started by peter radclyffe, May 21, 2014.

  1. powerabout
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    powerabout Senior Member

    I have them checked when sailing in Thailand
     
  2. powerabout
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    powerabout Senior Member

    A torqued up bolt should have stretched the bolt more then it ever will in use hence no extra strain and hence huge reduction in cyclic loading.
    Thats bolt stuff 101, how that might be used on keel bolts through fibreglass is stretching the theory a bit IMHO
     
  3. RHP
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    RHP Senior Member

    Good lord. :eek:
     
  4. powerabout
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    powerabout Senior Member

    you get that done when ashore
     
  5. MikeJohns
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    MikeJohns Senior Member

    Hi Chris
    Wasn't it a French boat in the Med. Unfortunately I've just moved and can't find the accident reports now so I could be mistaken. There were a number of production boats deficient in their keel-hull attachments and a number of deaths.
    Another North American 40.7 called Barracuda had the keel brake off after grounding. Which shouldn't have happened so easily. The updated ABS rules allowed for grounding loads as well as beeing the laminates up for the dynamic loads and fatigue.

    More recently the Cynthia Woods fatal keel loss was attributed directly due to the designer failing to meet the 94 version of ABS.


    If any GRP boat has backing plates alone and no connection through to framing them It's really being left up to owners to check that they have thick solid laminate, generally at least as thick as the keel bolts diameter that extends some way from the interface before the core starts. Don't expect the manufacturers to follow this up. It's considered the responsibility of the boat owner !

    I'm still not sure that the 40.7 is cored in that area, but it looks like it from the pictures, it's a mistake several other manufacturers made too with designs from the earlier ABS rules for offshore racing yachts.
     
  6. powerabout
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    powerabout Senior Member

    where did ABS do their crash testing to determine their specifications?
    same place they created the canting keel data?
     
  7. MikeJohns
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    MikeJohns Senior Member

    No it makes the bolted connected much more robust. The total strength doesn't change at all since the pre tension load and the applied load are not additive past the pre-load, the elastic response ensures that. (Think of a rubber band stretched between two fixed points that you stretch a little more).

    It also adds a considerable and necessary friction joint in the clamped area, this also stops the bolts bearing on the composite in shear.
    Pre-tension also ensured better load sharing.
     
  8. MikeJohns
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    MikeJohns Senior Member

    The 'Achilles keel' of the ULDB racer :)
     
  9. fcfc
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    fcfc Senior Member


    The 40.7 is NOT cored, except for the deck.
    There was NO report of another 40.7 loosing its keel except Barracuda that hit ground for HOURS before loosing its keel.

    There are not so much PRODUCTION boats (more than 5 unit built) loosing keels.
    I am aware of ONE Bavaria 42 match. But prior grouding was suspected.
    The third one was Sun Odissey 37 that cleanly sheared keel bolts grounding on rocks while motoring. The boat did not sink, did not capsize, and the crew even did not noticed they loose the keel.

    Very strange thing is that keel loss of the THREE production boats (more than 5 built) known as of today (First 40.7, Bavaria Match 42, Sun Odissey 37) occur on RENTAL boats, not on owner boats.

    NB Other boats that loose keel (Cynthia woods, maxfun 35) are NOT production boats. They are either one off, or racing prototype.
     
  10. powerabout
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    powerabout Senior Member

    does a rental boat means it hit the bottom or just does enough cycles to fatigue things?

    I have seen a beni 44.7 sitting on its keel ( as in planted straight up) once or twice at the Kings Cup, didnt even make a hairline crack, 44.7 is solid laminate
     
  11. fcfc
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    fcfc Senior Member

    But both the First 40.7 and Bavaria 42 match that lost their keels were rented for racing. And they were among the cheapest to rent for race.

    Another point: I cannot imagine Beneteau design office and Bruce Farr design office not matching at least ABS ORY 1994, since the boat was sold on the US market.

    For the Bavaria, also a big yard, it showed compliancy to CE rules.

    My current guess is rules for "recreational crafts" ie current ISO or older ABS ORY 1994 simply underestimate abuse taken by the cheapest (so probably the most easily rented) commercial boats rented for racing.

    Now, is the abuse is unreported grounding by customers not willing to pay damage, fatigue cycling due to continuous racing , or maintenance done on a budget (remember it is a commercial operation) I do not know. Probably a mix of the three.


    The real question is should "we" make ALL owners pay for a thing that 0.1% of owners will need (the one that buy the boat for commercial renting for race) , and 99.9% other "normal" owners will not need.
     
  12. powerabout
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    powerabout Senior Member

    It will come down to do you want insurance then take the keel off and inspect it.
    Rigging is like that, just replace it.
     
  13. Nick.K
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    Nick.K Senior Member

  14. bruceb
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    bruceb Senior Member

    keel bolts

    Some Beneteaus for the USA market are/were shipped with out the keels installed. Does anyone know the history on this boat? The installation instructions are very specific on bolt torque and sealants. Many yards are not equipped to properly tighten the bolts, and I think I remember a requirement to recheck the torque.
    B
     

  15. Nick.K
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    Nick.K Senior Member

    You've made some interesting points, but I don't understand exactly what you are asking here? You seem to be making the point that these boats only fall apart if they are used.

    Isn't the charter market a principle customer base for both Beneteau and Bavaria? and both Beneteau and Bavaria keep up their sales volumes by promoting shared purchase deals between the public and charter companies where ownership is transferred after a charter period. Poor deal for Joe public if when his turn comes around the boat is suspect because of heavy use.

    I can say with confidence that 99.9% of owners (crew too?) would prefer their keels to stay stuck whatever.
     
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