Official Synthetic Winch line Splicing Thread

[Inukshuk]

From all I have read (and I am still learning and will edit to correct as needed):

1. In all cases, the objective with synthetic rope is to avoid sharp radius bends (such as knots). Think of a knife edge being the sharpest possible "radius" and maybe that will help the explanation)
2. Brummel locks no better than a lockstitch. Brummel reduces strength because it is a bend. Handle rope well and even an unlocked deep bury will not come loose during handling. However, Brummel does not cause such a significant strength loss so as to be avoided.
3. "Locks" do there job when rope is being handled, not when under tension.
4. The point of lack of adequate taper is where most synthetic lines would fail, because the abrupt edge of the end of the buried tail is, in effect, a radius.
5. I will make my extensions with decent sized eyes, chafe guard and no thimbles, so I might run straps through, though in practice the ends will a most always be secured through screw pin bow shackles.
6. Chafe guard matters.

 

[DaveInDenver]

5. I will make my extensions with decent sized eyes, chafe guard and no thimbles, so I might run straps through, though in practice the ends will a most always be secured through screw pin bow shackles.

This is something I did not do, I wish I'd have just done eyes with chafe guards instead of a tube thimble at least on one end.

 

[rover67]

72 times the diameter... for real?

 

[DaveInDenver]

72 times the diameter... for real?

That'd be the conservative measure for class 2 rope. The chart is Corland, the graphics are Sampson.

 

[Inukshuk]

72 times the diameter... for real?

https://samsonrope.com/docs/default...trand_c2_eye_splice_web.pdf?sfvrsn=f00ad20c_2
has a three fid bury, taper starts at 1 fid from tail. fid is 7 3/4", so 23 1/4". 3/8 * 72 = 27
I read that dyneema is slippery

Another fun website is https://www.animatedknots.com/splicing-knots

 

[Inukshuk]

Made my first extension. From the 150' I should be able to put 77.5 feet on the winch drum,, some of which will not be useable length as it will be the initial wraps, and make two extensions of 20' and 40'. About 14.5 feet gets consumed in the splices, between the loops and burys.

 

[rover67]

So per Samson it's 62 times the rope diameter. If you use their fid and do a 3 fid bury which includes the taper.

The 72 is just recommended to be conservative

 

[Inukshuk]

Update:
my splices have held under load
I cut off some chafe guard. It was more than needed and jammed up the pulley block.

 

[Inukshuk]

Updates:

From all I have read (and I am still learning and will edit to correct as needed):

1. Brummel locks no better than a lockstitch. Brummel reduces strength because it is a bend. Handle rope well and even an unlocked deep bury will not come loose during handling. However, Brummel does not cause such a significant strength loss so as to be avoided.
2. Chafe guard matters.

Brummel locks are great
Chafe guards affixed to lines suck. In eyes are decent but not as great protection as a gusseted tube thimble or any type of thimble really. Coated/dipped eyes are well protected too.

 

[Corbet]

I’m going to put my question here for now as it’s seems logical verse starting a new thread.

Those of you who have built your own winch line extensions what kind of “eye” do you like on each end & WHY? I have seen:

just a plain eye of varied sizes
standard tube thimbles
some sort of protective sleeve, again varied size eyelet
dipped with some sort of rubberized goo
how about a hook on one end like a traditional winchline?

anyone cover your splice with heat shrink tubing?

If it matters I plan to stick with the hook on my winch. 60% of the time I connect that straight to my tree saver and pull.

 

[DaveInDenver]

@Corbet, I have two extensions, one with tube thimbles (standard bury, lock stitched, there's a photo earlier in the thread) and one with soft eyes using nylon tubular webbing as a protector and a Brummel splice locking it, very much similar to what @Inukshuk shows a couple of posts ago, minus the sliding chaff guard.

My feeling is the tube thimble is the one I trust for full rating. My reasoning is that rope is spec'd to have a minimum bend radius. It's specified as a ratio of bend radius to rope diameter.

For example:

So a rope that's 1/2" in diameter (d) bent around a radius of 5" is 5/0.5 = 10, thus has an efficiency of approximately 82% in this example chart. Efficiency in these terms means it retains 82% of the base rope's given breaking strength.

ETA: This article mentions several key factors in using Dyneema, including bend radius and throat.

https://www.ussailing.org/wp-content/uploads/2018/01/Dyneema-Spectra-Lifeline-Revision-Jan-2014.pdf

 

[Inukshuk]

I have soft eyes in 1" webbing but I think I will be rebuilding those with tube thimbles. Mostly for the rope-on-rope use with a soft shackle. OTOT, with soft eyes you can join extensions without any sort of shackle.
Dip can be ok, but not sure what it would be.
Mass of a hook is totally unnecessary

 

[Corbet]

How are you joining soft eyes without a shackle and still maintaining minimum bend radius?

I threw the hook variable in there just for you. 😂 Not really serious, but if one is going to use a steel shackle or a hook the mass is pretty much the same.

I forgot to note, I’ll continue to use steel shackles to connect where needed. I have plenty and don’t want to replace them all with soft. Might buy one for looping around things like a slider or roll bar.

 

[DaveInDenver]

How are you joining soft eyes without a shackle and still maintaining minimum bend radius?

I threw the hook variable in there just for you. 😂 Not really serious, but if one is going to use a steel shackle or a hook the mass is pretty much the same.

I forgot to note, I’ll continue to use steel shackles to connect where needed. I have plenty and don’t want to replace them all with soft. Might buy one for looping around things like a slider or roll bar.

The rule of thumb is to never go below 1:1 bend radius as a minimum (e.g. the bend is the same radius as the rope diameter), which is the approximate 50% point and less would risk shearing. Of course avoid any hard corners regardless.

The thing to remember mainly is that bend radii exist and you have to consider the derating you might have to do. If your force is 9,000 lbs and you have a 47,000 lbs soft shackle that is bent sharply down to 50% efficiency then you're still fine on paper.

You could do something like Burke with various things, like a rolled up magazine or a flashlight, to support the rope and preventing a knot in situations like that. This is shortening the rope IIRC but the principle looping eyes is similar.

 

[Inukshuk]

How are you joining soft eyes without a shackle and still maintaining minimum bend radius?

 

[Inukshuk]

I threw the hook variable in there just for you. 😂 Not really serious, but if one is going to use a steel shackle or a hook the mass is pretty much the same.

I forgot to note, I’ll continue to use steel shackles to connect where needed. I have plenty and don’t want to replace them all with soft. Might buy one for looping around things like a slider or roll bar.

Not ideal in the middle of rigging but if all your gear is in good condition and rated, nothing will break. But the steel likely breaks last so mid-rope is best to avoid.

 

[Inukshuk]

You could do something like Burke with various things, like a rolled up magazine or a flashlight, to support the rope and preventing a knot in situations like that. This is shortening the rope IIRC but the principle is similar.

Bill would no longer advise a flashlight or magazine in a winch rope shortening. OK if hi-lift winching. Very sturdy stick / oak closet rod is a maybe. Safe X-tract used to sell a high density plastic dowel, until one broke. Now they sell a solid aluminum dowel. https://medicalpointsabroad.com/product/winch-line-lock/

 

[Corbet]

Bill would no longer advise a flashlight or magazine in a winch rope shortening. OK if hi-lift winching. Very sturdy stick / oak closet rod is a maybe. Safe X-tract used to sell a high density plastic dowel, until one broke. Now they sell a solid aluminum dowel. https://medicalpointsabroad.com/product/winch-line-lock/

So add another metal piece of mass in the middle? Granted aluminum so less than a shackle. Connecting straps through two soft loops looks less risky with respect to radius than 3/8" Amsteel.

I think I'll go with tube thimbles on my extension and keep 100'+ on the winch drum.

 

[Inukshuk]

So add another metal piece of mass in the middle? Granted aluminum so less than a shackle. Connecting straps through two soft loops looks less risky with respect to radius than 3/8" Amsteel.

I think I'll go with tube thimbles on my extension and keep 100'+ on the winch drum.

You are conflating issues. Line shortening vs. line connecting.
For most general situations and a best-practices approach, 100'+ on the drum is not supported by science or empirical evidence. Just saying it here so others hear it.

 

[DaveInDenver]

Bill would no longer advise a flashlight or magazine in a winch rope shortening. OK if hi-lift winching. Very sturdy stick / oak closet rod is a maybe. Safe X-tract used to sell a high density plastic dowel, until one broke. Now they sell a solid aluminum dowel. https://medicalpointsabroad.com/product/winch-line-lock/

That video is by far better at showing what I had in mind. Post edited accordingly.

Back to Corbet's point. I have 60' spooled on the winch.

50' tube thimbles, straight bury, lock stitch and whipped


30' soft eyes and Brummels