Cayo,
See this thread:
http://briontoss.com/spartalk/showthread.php?t=2094 for some discussion on my rigging notes, and consider it was the lower (not cap shroud) tang plate which broke, which under Toss's equations, if I read them right, puts a design load of 6648 lbs at 2.5 safety factor on the lowers, in total. This, with its attendant safety factor, is still about half of the breaking strength of Colligo's tangs, as advertised. Therefore I stand by the "massively overengineered" statement as John and I had discussed on the phone. Per the tested breaking strength of the tangs, they should have been massively overengineered and I don't fault John's math in his design work. Which is why I believe that the tangs had a defect in manufacturing or that the bend line, where they fractured, excessively weakens under day to day loading and that this was either not taken into account, or, to believe John that it was, that something in his manufacturing process causes it to be weaker over time than his calculations assumed.
Jim, the tangs fractured cleanly in half, as shown in the photographs. Thus retrieval was as simple as picking them up by the shrouds. I was not able to remove the parts left on the mast. I'm not sure how I gave the impression that I did from your pull quote, unless you are assuming that having two pieces means the tang was originally a single piece, which it was not - it was a double plate tang assembly.
John,
Precisely - the spreader was intact. Given that I could see the starboard spreader, and that under starboard tack upwind the port spreader had effectively no load on it, it is not conceivable that a catastrophic failure of the port spreader would be either possible nor contribute significantly to such an intense shock load as you speculate. So in fact my statements are consistent and continue to point to the fact that there was no observable cause or indication of shock loading from another failure, particularly the regions under high stress at the time which, particularly according to your suspicions, would include the spreader. I continue to respectfully disagree with you that some hypothetical catastrophic failure of another part, the evidence for which does not exist and supporting evidence against which does, caused such an intense shock loading on the lower shrouds as to fracture a titanium tang cleanly along an area which was not a weak spot and was in fact as you say engineered to be four times the strength of a weak spot - all without leaving any indication of stress on any of the six bolt holes which you state were the designed weak spots and you agreed on your own inspection show zero evidence of overloading. It just doesn't make sense.
The other boat, who has, according to my phone conversation, visible witness of the chain of events of their situation, will be contacting you independently and I will feature their story or encourage them to do so once they have had some time to recover from the shock and deal with their damaged boat. I do not wish to press them too hard at this time, but suffice it to say their story will be more conclusive than mine if our initial conversation is any indication. I'm sure you will hear from them in reasonably short order.