Docklines

[Dan Lehman]

Originally Posted by ajstrange

Hello Brion and all,
I have an ongoing argument with my superiors that tucking a West Coast taper into a dockline will reduce the breaking strength. Besides the word of Master after God, is there a reference on paper that I can help prove my point?
Thanks, Amy

Let's turn the question around : =>> Is there any reference that can prove *their* point?!
How do they come to their beliefs? (Have they ever broken a splice, or even a knot?!)

Frankly, a better question is So What?!!
Do they endorse practices that make the difference in splice strength at all relevant
(they better not)?! -- or even that of a knotted eye, for that matter.
We're talking upwards of 50% on the line of its new strength,
and such a load indicates something gone quite wrong -- maybe line sizing.
One otherwise has to postulate that there's some real chance that some extraordinary
event will fall >>just<< in the relatively small window between whatever two strengths
one is arguing over -- say, 92% for Splice-A vs. 84% for Splice-B, when expected
usage should be below 30%. So along comes something and yet it
is only JUST extraordinary enough to break the lesser thing!

Frankly, the suggestion that a taper weakens a splice, to my mind, points to a rationale
that would change the splice: that the taper weakens by simply lengthening the
amount of rope that is torqued a bit to accommodate inserted material. And that
to improve strength one should lessen the number of full tucks if putting in some
tapered tucks.

"By-Strand Taper" is a better name than some dubious geo-political one,
though marketing types might prefer the fluff. It is a taper effected by whole
strands, after all. What sort of splice were you doing? I've seen things as
brief as -- to adopt a nomenclature apt for this splice -- "3-4-5" & I think even
"2-3-4", where the numerals denote number of tucks in respective strands.
(Realize that the spliced-back-into-rope end is going to bear only about 50%
of overall load, so it hardly needs some perfect working.) (The CapeMay-Lewes
Ferries are one place where I've checked this.)

Beyond the lack of good testing,
one might ask if testing has been done on USED splices -- i.e., tested after the
structure has endured some period of use. Maybe one form endures better than
the other, which might look good upon initial, new-rope, & slow pull testing.

And beyond all of this, one might put on some whipping, to help security.

--dl*
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