Docklines

[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

[Brion Toss]

Hi there,
The destruction-testing we've done has shown that any standard taper weakens nylon a bit. I have yet to test the West Coast (Frisco) taper, but you know, even if it came out well, I'd be disinclined to use it, just because it looks so, well, gawmy. If you are going to taper, do a real taper.
Fair leads,
Brion Toss

[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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