Synthetic fibres -- objective performance ratings?

[Justaddwata]

My disappointment at the Sail test was that they failed to reference the pin diameter. The larger the diameter of the pin the greater the load on the knot. Also the diameter of the eye formed (by knot or splice) is also important info for reference.

I worked with Brion some time ago when he was reviewing knots in HM ropes. He did a write up on the subject also.

Back to the original topic of the thread. Comparison tests are only as good as the test method used. Repeatability and consistancy of the aparatus and method is the only way to make a test that yeilds usable data. There are so many ropes, tests, reviews, experts, and final applications that it is a daunting task to consider. I have seen several good abrasion test methods and know NER had done some work with these methods in evaluating chafe of mooring pennants.

The use of PBO in jackets is for its resistance to extreme heat and abrasion. The fact that its life is not much longer than that of milk when in the sun seems of little consequence to those with big budgets and high expectations.

When it comes to bears chewing through Vectran Vs Spectra - you may want to consider if this is abrasion or shear. Spectra is certainly superior in cut resistance - but that is not abrasion. My experience has been that Spectra and Vectran are comaprable in an abrasive environment. I have never done an apples to apples test to distruction of both Spectra and vectran. Spectra will certainly have an advantage with how slick a surface it is. But again - with the testing. You would have to consider under what load such abrasion would be occurring, what braid is used for each, How rough a surface etc.

I am interested in seeing more testing. Strength loss over varying radius. Tensile breaks at varying travel rates. Abrasion of different fiber types, different braid types, different loads, different abrasive surfaces. UV Degridation. Shock loading. and so on.

[Renoir]

Sorry Dan, I should have qualified further the reasons for my liking the Carrick bend. This bend is easy to tie, easy to untie and strong and can be used with widly varrying diameters and types of line mixed.

The bends that you mentioned are qualified by their being confined to using lines of fairly equal diameters. The Grapevine can be a bitch to untie after it has been subjected to a heavy pull in water. I do like the symmetry, however, of those that you mentioned. I truly don't know how to choose between an Ashley #1425 and the Zeppelin or Rosendahl's bend....any suggestions?
Thanks

[Dan Lehman]

Originally Posted by Renoir

Sorry Dan, I should have qualified further the reasons for my liking the Carrick bend. This bend is easy to tie, easy to untie and strong and can be used with widly varrying diameters and types of line mixed.

The bends that you mentioned are qualified by their being confined to using lines of fairly equal diameters. The Grapevine can be a bitch to untie after it has been subjected to a heavy pull in water. I do like the symmetry, however, of those that you mentioned. I truly don't know how to choose between an Ashley #1425 and the Zeppelin or Rosendahl's bend....any suggestions?
Thanks

I've seen another way, but I tie the Carrick in the capsize-the-lattice-form way,
and with different rope types, that will be somewhat tricky. I got my numbers backwards
or my "former" lattered, but #1452--what Day got started as "Ashley's Bend"--is quite
like the Carrick but for being stronger (in some misc. testing), and more secure; it has
a few ways of being dressed/oriented, though. (Another interlocked-Overhands bend,
called "Shakehands" by Harry Asher, and now in some knots books, can similarly be
seen as a derivative of the Carrick.) #1425 can also handle mismatched ropes within
as much range or more than I'd think a Carrick could.
Rosendahl's bend presents two broad, flattish faces, with ends coming out on small
sides to these, so to speak: makes for taking knocking about abrasion pretty well.

Whizz-bang tying methods have been invented for both 1452 & Rosendahl's, both of
which impress me as too clever by half--one must mind picky details in order to get
the final effect; I much prefer to form one Overhand in rope, and then choose how the
2nd gets formed into it (to make 1408 or 1452 or 1425 or ... or Rosendahl's or ... ).

Again, on the strength of the Carrick, I've not seen much testing--just a lot of echoes
of the rumor (Ashley's?); it does not LOOK so strong to my eye, in terms of material
curves (part of the picture).

--dl*
====

[Renoir]

I'll give these a try. The knots that I use under pressure are all those that I can remember to tie easily like the usual basic ones and the butterfly, carrick, prusic and, yes, I've even used a sheepshank to shorten a line that quickly will have a strain on it and, therefore, it doesn't come undone.