How strong?

[zoidberg]

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.

[vyv_cox]

Equivalent to asking the same question about 'steel'. Totally dependent upon what alloy we are talking about.

[vyv_cox]

Grade 5 seems most probable for this application. UTS about twice that of 316 stainless steel according to Wiki.

[Poignard]

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

What are you considering using it for?

[boomerangben]

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

[sarabande]

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

http://www.ybw.com/forums/showthread...ghlight=jordan

[doug748]

4 big heavy tons, is my guess.

PS
Just read it properly, 2 big heavy tons

[johnalison]

With four holes, could you not turn the ring through 90 degrees and regain some of its designed strength?

[SAPurdie]

I'd ask Harken, apparently they made it.

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

[zoidberg]

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'.