Soft Halyard or Line Shackle

[allene]

Originally Posted by Brion Toss

Hi all,
Here are a few details from the tests.
First, as noted previously, the best numbers came with shackles that had been cycled at 50% of the average tensile result of shackles that had not been cycled. So if we broke 5 shackles, and they had an average break of 10,000lbs., then they cycled a sample up to 5,000lbs, ten times, before taking it up to break. This added about 20% to the shackle strength for most of the samples we broke.
Next, the smaller shackles did the best, with one notable exception. The average of uncycled breaks for 5/32" was 260% of rated strength, which dropped down to 195% for 3/16" and 141% for 1/4". But the 11mm HSR, New England's heat-treated rope, broke at 166% of rated strength (over 52,000lbs.)
Even the lower numbers were well in excess of numbers we have gotten with conventional soft shackles,. Most heartening.
Most of the tests were done with a lanyard through end of the shackle, and a pin at the other, though some were attached to a lanyard at both ends. The HSR started cutting through the lanyards at high loads, so the testers had to insert thimbles for those. With that exception, then, these numbers were for very tight bends, on the order of 1:1. This means, among other things, that we are safe using them to join rope to chain for anchor lines.
Most of the samples broke at the end of the tail bury, so the taper is one of the things I'll be adjusting in the next batch.
I'll be working with the wonderful tech people at New England Ropes to analyze this data further, and to prepare for future destruction.
Fair leads,
Brion

Hi Brion,

What did you use for a taper?

Very impressive results. It does start to bring up the concern that these loads get high enough you have to start to worry about the soft shackle cutting through any rope it might be securing. I have wondered if you are securing an eye splice in StaSet, what ratio of shackle and strength starts to move the failure mechanism to failure in the StaSet? Obviously not a concern when securing chain.

Allen