Synthetic winch rope

[Lynn]

At the suggestion of a friend I tried that knot too and it also failed.

However, since I am not accustomed to doing so I didn't use any stopper knots and that may make the difference.

I'm curious as to how these knots were failing. Were they slipping or was the rope breaking in the knot?

I haven't worked with winch rope, but from what you've posted so far it sounds like maybe they were slipping. If that's the case, maybe the double fisherman's is the best knot. It was designed, after all, to hold monofilament line, which is notoriously hard to tie.

Or, to revisit what you said earlier:

...I consider poly winch lines to be only spliceable and not knotable...

Maybe anyone who used synth winch rope should just plan on splicing? From what you said, it sounds like you have a hollow braid line, which is almost as fast to splice as it is to knot... However, hollow braid splicings can also come loose if they are repeatedly loaded and unloaded. They should be checked before each loading.

 

[ntsqd]

What I tested was Amsteel (not Amsteel Blue) in 1/4" size. I choose this size b/c I was interested in spooling more line onto my cable-less Warn M8. The Amsteel instead of the Amsteel Blue came about b/c that was what I could buy by the foot locally. Had the 1/4" Amsteel performed better I'd have asked Scott Ellinger @ Rockstomper to order a 600' spool of 1/4" Amsteel Blue & found enough other buyers to make it worth his trouble. Given the performance of the Amsteel, the difference in their numbers didn't buy me enough F.S. to be comfortable with going down that path.

These are a 12 strand woven (not laid) line. The mfg recommended eyelet splice takes advantage of it's being hollow in a "chinese finger trap" sort of way.

Every knot, when loaded, caused a separation failure of the line. The parting points characteristically all looked melted. The appearance looked like if you pull Surveyor's string tight and then hold a lighter under it. It has been a while since I did this testing, but my recollection of the separation point is that it consistently was where the live end encountered the first wrap of any sort in the knot.

I have two possible explanations of what the failure process is. The first is that tight bends in the line are stress risers, and that stress is released in the form of enough localized heat to weaken the line enough for the loading to pull it apart. The second is that, no matter how tight you set the knot, line loading causes the knot to further constrict and that relative movement generates the localized heat.
I take note that a sharp edge on a rock or anything else is also likely to cause this sort of failure.

In any case, these are all short term field repair methods. I doubt the ability of a knot to spool onto the winch drum. A Long splice probably will, but will upset the lay of the line on the drum.

I also tried 2 splices, the mfg recommended method for an eyelet (which requires a splicing fid) and the flat lateral weave I previously posted. Neither failed first, the knots always gave up first.

 

[craig]

Hmmm.... Did the knot fail, or did the rope fail at the knot?

In our case the knot was tied on 5/16" winchline.com Viking Trail line (Amsteel Blue) and was used to lug a 5000lb truck uphill through snow drifts several times the rest of the day.

Photos attached just to keep the thread lively.

White D1 - Chris (Coast Guard guy) running cable
Red D2 - Andy - running the broken rope

Craig

 

[craig]

Yeah, these are all just temporary repairs. Splicing is just as easy, and is something everyone should learn how to do. It is extremely easy. No more difficult than running the string through swim trunks with a safety pin. The FID is the safety pin. You can use anything long/skinny along with some electrical tape as a FID (E.g. pen/pencil).

The guys at winchline.com said the same thing as you suggest about why the knots cause failure. That is because they get bent too sharply causing the fibers to abrade against each other. The friction and subsequent heat would definately cause the melting you saw too.

Craig

 

[ntsqd]

snip......
Hmmm.... Did the knot fail, or did the rope fail at the knot?

AIR The line itself failed at the knot's first wrap around the line. Can not recall a knot failing internally.

Should also mention that the flat lateral weave type splice was roughly 5 times faster to execute. Could make a difference in some situations.

 

[paulj]

Article regarding possible use of synthetic line in logging:

http://www.clas.ufl.edu/users/jhart... Wire Rope in Mountain Logging Operations.pdf

 

[Photog]

So, after all the knotty discussion, it sounds like the synthetic rope is easier to repair than wire rope; just learn how to splice. How would you repair a wire rope? How long would that take? How strong would it be? Could you wrap it onto the winch drum?

THE ORIGINAL QUESTION in post #1:
"Synthetic winch rope ... any good? Know the strength is spot on and better than wire rope, carefull with dirt on it bt but main concern, how does it handle extended exposure to harsh UV radiation (like what we have in Africa). EXpected life span?"

Here is an excellent article about the durability of synthetic line for winching.

http://www.bb4wa.com/articles/amsteel2.htm

 

[charlieaarons]

Wire rope is very easy to fix if broken, but I've never broken one in 34 years of winch-using. I carry some cable clips. You can either make 2 new eyes and connect them with a shackle or just clamp the two pieces together. They won't go thru a typical light duty fairlead but will go thru the fairlead on my front winch (20K DP hydraulic with 9/16" cable).
I still don't trust synthetic line; these discussions about knots failing due to heat confirm my doubts. And who doesn't drag line thru the dirt or over rocks?
Did you all know that 80-90% of the input energy into an electric winch goes into heat? Proof: Warn 16500, 3'/min at max load = 49500 ft-lb/min = 0.9 hp output. Input: 507A X 12V = 6.08kw = 4.56 hp. So 80% = 4800W goes to heat; enough to heat a small house! or to melt synthetic line.
Do the numbers yourself from the winch mfgs sites if you don't believe me.
Charlie

 

[Photog]

Charlie, Does your rig need wire rope due to the weight of the rig? Do the cold temps of Alaska have any negative effect on either type of rope? I have never broken a wire rope either; but that usually isn't the problem with wire. It is all the kinking, coiling, wires that cut your hands (even through gloves), corrosion, cleaning, oiling (waxing), etc.

To everyone else:
For those worried about heat and dirt, the article listed above, suggests that heat and dirt are not the problems the wire rope folks make them out to be. The guy that wrote the article uses his winch more in a month, than most of use will ever use our winches. Field experience is worth more to me, than armchair theorizing. Experience shows not much of a problem with heat & dirt. Move on.

The fellow that did all the testing with the knots found out that rope breaks at the knot. Real experience. All ropes will break at the knot, even wire rope. Big suprise. If you need full line strength, don't fix them with knots. If you only need 50% line strength, there are many knots that will work just fine. But; his real world experience showed the need to learn how to splice. Problem solved. Move on.

Mountaineers and rock climbers learn how to protect their ropes, over abrasion points. This would be no different. Problem solved. Move on.

There are so many drawbacks to wire rope, and so few for synthetic rope. And all the "problems" with synthetic can be solved. Not so with wire.

Do they both work? Yep. Do they both need a certain amount of care? Yep.

I think I will go with synthetic, for the situations a 4X4 rig will see. Did I miss anything that relates to off-road or expedition use of a winch? I could still get a wire rope for the winch, if there is a compelling reason.

OK, time to cool off. It is Friday, and I need a brew.:wings:

 

[paulj]

Regarding the flat lateral weave - is this done by spreading strands to make a hole in the middle of the line, and then passing the end through that hole. And then repeating the process a half dozen times?

paulj

 

[charlieaarons]

Charlie, Does your rig need wire rope due to the weight of the rig? Do the cold temps of Alaska have any negative effect on either type of rope? I have never broken a wire rope either; but that usually isn't the problem with wire. It is all the kinking, coiling, wires that cut your hands (even through gloves), corrosion, cleaning, oiling (waxing), etc.

Do they make synthetic winch line in bigger diameters? Of course they do make superstrong synthetic lines in all sorts of diameters, I just suspect you'd have to find something with good abrasion resistance and a low stretch coefficient in the 25-40,000 lb category. My rigging shop has a display wall full of different synthetic lines, including some really nice stretchy stuff for snatching in 1-3/4" that I'd get if I didn't already have a 40mm Marlow line.
I try to avoid activities that involve winching when it's very cold out.

Charlie

 

[Photog]

That blue line has very low stretch. That is part of the reason it does not store a lot of energy (if it were to break). it does not "slingshot" like the wire rope.

 

[ntsqd]

Regarding the flat lateral weave - is this done by spreading strands to make a hole in the middle of the line, and then passing the end through that hole. And then repeating the process a half dozen times?

paulj

Imagine looking at the side of line. Take a pencil or similarly semi-pointed untensil and poke a cross-ways hole thru it, working to make sure that you don't split a strand bundle around both sides of the hole. Push the end of the line thru the hole, and pull enough thru to repeat several more times from alternating sides.

Keep in mind that this is NOT any sort of approved splice method. It was borne from experimentation with the thot of "Gotta get this spliced b4 those guys can no longer keep that truck from rolling" kinds of scenarios. I was looking for a fast, simple knot replacement and this worked.


I failed that 1/4" Amsteel many times during the testing. Even with only a couple feet of cable played out every time the hook and steel cable from the 8274 being used to pull on it became a hazzard to all of us, but the Amsteel would recoil less than a foot and fall to the ground.
The energy stored in the poly line was mostly the loose weave being pulled tight. As soon as they were loose again, no more energy.

When we quit trying knots & moved to splices we started moving the 'anchor' and had to improve that as best we could. The anchor was a 2wd GM Crew Cab SRW with a loaded service bed. It was my friend's expedition-tow-racer chaser-rescue-baja rig, affectionately known as the "Behemoth". One side of the box was all tools and the other had all their camping gear. We had it in park with the e-brake set while sitting on the asphalt street in front of his house and were dragging it backwards with that 1/4" line. Chocking the rears finally stopped it from moving.

IMHO the double solution to the UV and abrasion concerns are the abrasion sleaves sold. If you get them long enough or enough of them they will cover the whole top wrap on the spool, and you can slide them along the line to whatever point(s) are a concern.

 

[paulj]

I think you are making something similar to Brummel splice.

http://www.neropes.com/SPL_12Strand_EyeSpliceBrummel.aspx

Actually this link is for a locked or mobius brummel, in which the parts pass through each other. Your's may be a stiched brummel, since the tail is passing through the standing part several times.

http://www.instructables.com/id/EAZH7SUT30EP286A98/

The locked version is more secure, though applying a whipping to your splice should improve its strength.

I don't have any of this blue line around, but it sounds as though its construction is similar to the inexpensive yellow polypro line (a single hollow braid). I'll have to play around with some of that.

paulj

 

[paulj]

There are a number of papers and conference presentations on research done at Oregon State into using rope like Amsteel Blue in logging. This is the most interesting, as it focuses on splices and connectors:

http://www.cbs.state.or.us/osha/pdf/grants/osu/runninglines.pdf