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Thread: How strong?

  1. #1
    Join Date
    Nov 2016
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    2,790

    Default How strong?

    I have a couple of these devices, in titanium alloy, and invite thoughts on the UTS of the upstanding loop, in a direction parallel to the baseplate.





    No, Harken don't know.

  2. #2
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
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    22,133

    Default Re: How strong?

    Equivalent to asking the same question about 'steel'. Totally dependent upon what alloy we are talking about.
    Answers to some technical queries at new website http://coxeng.co.uk

  3. #3
    Join Date
    May 2001
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    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    22,133

    Default Re: How strong?

    Grade 5 seems most probable for this application. UTS about twice that of 316 stainless steel according to Wiki.
    Answers to some technical queries at new website http://coxeng.co.uk

  4. #4
    Join Date
    Oct 2018
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    A Member State of the European Union
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    7,639

    Default Re: How strong?

    I suppose someone's bound to ask so it might as well be me

    What are you considering using it for?
    "Brexit: like watching a library being burned down by people who can't read"

  5. #5
    Join Date
    Jul 2003
    Location
    Isle of Lewis
    Posts
    539

    Default Re: How strong?

    Probably more than that of the screws that hold it down and maybe the substrate its attached to? If loaded parallel to the deck only two screws are holding it down

  6. #6
    Join Date
    May 2005
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    up on the moors.
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    33,406

    Default Re: How strong?

    Would my gallant and honourable friend find some useful information in an earlier post ?

    http://www.ybw.com/forums/showthread...ghlight=jordan
    I think, therefore I am. I am, therefore I sail.

  7. #7
    Join Date
    Oct 2002
    Location
    Plymouth
    Posts
    8,791

    Default Re: How strong?

    4 big heavy tons, is my guess.

    PS
    Just read it properly, 2 big heavy tons
    Last edited by doug748; 08-11-19 at 17:30.

  8. #8
    Join Date
    Feb 2007
    Location
    Essex
    Posts
    23,280

    Default Re: How strong?

    With four holes, could you not turn the ring through 90 degrees and regain some of its designed strength?
    Far away is near at hand in images of elsewhere

  9. #9
    Join Date
    Apr 2005
    Location
    Shoreham - up the river without a paddle.
    Posts
    1,253

    Default Re: How strong?

    I'd ask Harken, apparently they made it.

    The weld quality is the major player in this design so not easily calculated.

  10. #10
    Join Date
    Nov 2016
    Posts
    2,790

    Default Re: How strong?

    Sarabande's memory is in rather better fettle than mine, alas, and Major Clanger et all had good input to make.

    The 'bits' are to be mounted, each, on the quarters of a 6-7000lb AUW keelboat - not onto the transom. So think 'shear'. Something akin to a Jordan Series Drogue will be attached, probably using 2 professionally-sewn lifting strops, with known capacities, as the stern bridle. These will be rated to 'fail safe' before the setup can pull chunks off the stern of the boat, although it is unlikely that the string of 100 or so cones will develop enough resistance to pull the back end off the boat.

    As for 'Ask Harken'..... I did, of course. They have nothing in their archives relating to those, or other, 'Special Projects'.

    As I recall, Don Jordan's ideas for 'capacity' and 'peak loading' are based on 70% of max AUW - which was ( too often ) taken to be a boat's displacement. Most didn't work on LOADED displacement, so some JSDs were manufactured, sold and used which proved significantly under-spec'ed for the task.

    Several competent types, over on Cruisers Forum, are working on improvements. That's not unreasonable, given the advances we've seen in materials technology in the near-30 years since Jordan did his work. He didn't have much of a budget, using the materials he had to hand and which most cruising yotties to expect to source, but already peeps now make their cones from much tougher fabric than the original Dacron sailcloth, and the use of 3-ply laid nylon rode is 'not thought optimum' when single-braid HMWPE is now readily available. The best way to join bridles to rodes is being explored, as is the use of unnecessary knots.

    But, there's no budget for testing to destruction. Certainly, established ideas are being challenged, improvements sought, but the numbers involved are tiny. The opinions of every experienced long-distance cruiser who has used a JSD are analysed, pored over, debated. Some views, of course, carry more weight than others...... just like here. Such as that of 'Ming-Ming's Roger Taylor - 'I wouldn't go to sea without one'.

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