A concern about the Arborist Splice

[RonReese]

Originally Posted by Dan Lehman

Maybe I'm thinking of a different whipping than is commonly employed?
Tying extended Strangle or perhaps (Dbl.) Constrictor knots in strong material enables
a good deal of tightening to be done (a man can easily pull with 60-100+ # force on the
ends). This I'd think would give good assurance against low-load shifting.

It is claimed that splices retain up to 100% of the rope's strength. That kind of strength retention, as explained by Brion, SherrillTree, Samson Rope, One Rope 1, comes from the integrity of the splice rather than the whipping or stitching method. Most seem to readily admit that whipping/stitching only serves to keep the splice from slipping at very low or no loads or from mishandling.

If the splice itself maintains nearly 100% of the rope's strength then a good, strong, tight whipping or the best stitching isn't going to make it 110%.

In fact, such tight whipping could diminsh the strength of the splice by creating stress concentration at the whipping. This is a commonly known phenomenon in structural materials and design.

Originally Posted by Dan Lehman

What is "invisible stitching"? Don't you have to bring the thread to the rope surface both as a methodological necessity but also in order to bind the sheath--the point of it?! And if so, then that thread's vulnerable. (As for knowing about the bury, well, what possibly can happen to it?)

I would think that stitching does expose a small portion of the thread to abrasion, but whipping is totally exposed, 360? around the splice. But it's a bit of a moot point since the stitching/whipping does not add strength to the splice.

Originally Posted by Dan Lehman

Indeed! And the answer might be something like learning how sausage is made, not terribly attractive. I think that Tom Dunlap (arborist) and some others have some insights to some of the motivations behind some rules, and IIRC, they don't all seem so compelling.

LOL! Well maybe. But I like sausage, and whether the means is attractive or not, doesn't change the palatability of sausage.

But really, we're just expressing opinions and I'm not sure what those opinions are based on. In my field, engineering, I commonly see things being done a certain way because they've always been done that way and nobody knows any other reason for doing it that way.

Sometimes that approach is successful, but in some cases it breaks down because it's been a bad practice all along, and nobody knew it until it showed up one day.

FOR EXAMPLE - I was hired to interface a computer to a fire test laboratory. They test the flammability properties of all kinds of materials. The idea was to computerize the data collection and calculations which I did. Well, except for one calculus based calculation which I had worked on for hours and couldn't get the same answer they got. Finally, with the "top dogs" and technical staff present, I asked them to show me how they calculate this one parameter. As soon as they showed me, I took a deep breath and said, "You know that's not correct don't you?" They didn't even hesitate to admit that they knew it was inaccurate, but that's the way they had always done it. I asked what they wanted me to do and they said make the computer calculate it the way we do. I was done in five minutes and they were happy.

So until we put our splices and stitching and whipping opinions and/or practices to a real test on a tensile machine, we're just doing what we think makes sense to us with little support other than our experiences in the field that may not ever approach critical loads like a tensile machine would.