Comparing techniques used for eye splicing double braid polyester (=Class 1)

[Juho]

Originally Posted by Seaworthy Lass

Any feedback from anyone regarding this?

Instead of commenting the words in post #133 and the other posts I'll present one extreme splice type. The idea is that this splice to some extent stretches the limits of what a good splice might be, and what kind of parameters (lengths of different parts) it might have. Maybe pointing out the extremes gives us a good understanding of the whole field.

This example is a slim spliced loop. I'll use terminology of the figure below.

Core will be cut very early, at point L'. It will be tapered heavily in a cone shape, starting e.g. at C'. Cover will end roughly where it ends in the figure. Also it will be tapered in cone shape, starting e.g. at C. The thickest part of the splice will be between C and C', but also there the splice will be less than two covers and one core thick. Since the splice will be slim, and the pressure from the outmost cover therefore lower, segment ER will be quite long. One can also stitch the whole ER segment before it will be milked in.

If bulky splices are considered weak, then this one could be quite strong. If the flat loop is a problem (weak or otherwise uncomfortable) it could contain some core, just as a filler, not taking part in sharing the load.

If unbalanced cover and core are considered to be a problem, this splice allows in principle changes in that balance. Those changes would change the size of the loop, but let's say changing loop size is not a problem in our use case. The splice would have a long RC to keep the crossover point always inside the outmost cover. Good flexible balance might make the splice stronger.

One could have also such special variants of this splice where the length of cover segment EC is zero (CL (cover) would be longer), or where the length of core segment C'L' is missing (EC' (cover) would be longer).

Is this a working splice? Are the proposed good properties real? Is there a need for slim splices?

[Seaworthy Lass]

Originally Posted by Juho

Instead of commenting the words in post #133 and the other posts I'll present one extreme splice type. The idea is that this splice to some extent stretches the limits of what a good splice might be, and what kind of parameters (lengths of different parts) it might have. Maybe pointing out the extremes gives us a good understanding of the whole field.

This example is a slim spliced loop. I'll use terminology of the figure below.

Core will be cut very early, at point L'. It will be tapered heavily in a cone shape, starting e.g. at C'. Cover will end roughly where it ends in the figure. Also it will be tapered in cone shape, starting e.g. at C. The thickest part of the splice will be between C and C', but also there the splice will be less than two covers and one core thick. Since the splice will be slim, and the pressure from the outmost cover therefore lower, segment ER will be quite long. One can also stitch the whole ER segment before it will be milked in.

If bulky splices are considered weak, then this one could be quite strong. If the flat loop is a problem (weak or otherwise uncomfortable) it could contain some core, just as a filler, not taking part in sharing the load.

If unbalanced cover and core are considered to be a problem, this splice allows in principle changes in that balance. Those changes would change the size of the loop, but let's say changing loop size is not a problem in our use case. The splice would have a long RC to keep the crossover point always inside the outmost cover. Good flexible balance might make the splice stronger.

One could have also such special variants of this splice where the length of cover segment EC is zero (CL (cover) would be longer), or where the length of core segment C'L' is missing (EC' (cover) would be longer).

Is this a working splice? Are the proposed good properties real? Is there a need for slim splices?

Are you into extreme sports as well?

Biggest problem I can see is that nothing is gripping the end of the core well any longer, so line strength will become cover strength.

If the core is somehow gripped, as far as I understand, the proposal is based on the assumption that the cover is responsible for 50% of the strength of the rope. I am not sure that is correct, but if it is, this is likely to apply only to brand new rope. As soon as it is exposed to UV and chafe (likely at the peak of the eye unless you were adding a thimble) the breaking strain would decrease and fall below line strength.

The above would be the splice maker's equivalent of highlining on a moonless night .

But you are right, thinking of the extreme case does make us focus on the properties of various components of the splice. An interesting exercise.

SWL

[Juho]

Originally Posted by Seaworthy Lass

Are you into extreme sports as well?

Biggest problem I can see is that nothing is gripping the end of the core well any longer, so line strength will become cover strength.

I think we need to answer the question if 2*cover is as strong as cover+core.

If the core is somehow gripped, as far as I understand, the proposal is based on the assumption that the cover is responsible for 50% of the strength of the rope. I am not sure that is correct, but if it is, this is likely to apply only to brand new rope. As soon as it is exposed to UV and chafe (likely at the peak of the eye unless you were adding a thimble) the breaking strain would decrease and fall below line strength.

Yes, a thin rope has more surface area that could be harmed somehow. Note that also in some more traditional splices the tail of the cover is not buried very deep, which could leave close to half of the load to a cover segment on one side at the root of the loop.

The slim spliced loop may not reach 100% strength, but it could be close, depending of the type of the rope. An ideal spliced loop would be >100% strong, but I have understood that in tests it is still common that the splice (or rope right next to it) breaks before the rope does (i.e. <100%). Maybe a semi-slim solution could reach the best of both worlds.

The above would be the splice maker's equivalent of highlining on a moonless night .

But you are right, thinking of the extreme case does make us focus on the properties of various components of the splice. An interesting exercise.

SWL

[Seaworthy Lass]

Juho, I have just finished comparing the marks and lengths used in 11 Class 1 splicing methods.

It has been absolutely invaluable. I have learned heaps. I will email this data when I have checked it. I have only looked at most of the videos/pdfs once and it is easy to make errors.

The "winner" in my opinion (and this based purely on what I think are desirable characteristics and much of this is no more than inexperienced "gut feeling" at the moment and having a play with making a few splices) is the YouTube made by Wes Spur. Jedi posted that link. It is almost the same as the Samson one, with a few slight modifications.

It has room for improvement though if some of the best features of other methods were added (eg I like Brion Toss's stitching of the crossover point using a pulled "yarn" from the core) and I have a couple of suggestions as well such as applying some gradual but then sustained load (easy to do on a winch) before finally adding a few lock stitches (again, Brian's idea of using a thread of cover for that is a good one - high strength is not needed there). No one seems to do that before lock stitching and I think it would be beneficial.

I very much doubt all 11 lots of these eye splicing are equal. The easiest take shortcuts that I think will ultimately affect eye splice performance or that of the line adjacent to it. The most difficult to follow (for me that was the Sailrite video) are not necessarily the best either.

Anyway, these thoughts are all still milling around. I will sleep on it and look at the methods again next week.

Some discussion here would be very useful.

SWL

[Juho]

Originally Posted by Seaworthy Lass

Juho, I have just finished comparing the marks and lengths used in 11 Class 1 splicing methods.

It has been absolutely invaluable. I have learned heaps. I will email this data when I have checked it. I have only looked at most of the videos/pdfs once and it is easy to make errors.

The "winner" in my opinion (and this based purely on what I think are desirable characteristics and much of this is no more than inexperienced "gut feeling" at the moment and having a play with making a few splices) is the YouTube made by Wes Spur. Jedi posted that link. It is almost the same as the Samson one, with a few slight modifications.

It has room for improvement though if some of the best features of other methods were added (eg I like Brion Toss's stitching of the crossover point using a pulled "yarn" from the core) and I have a couple of suggestions as well such as applying some gradual but then sustained load (easy to do on a winch) before finally adding a few lock stitches (again, Brian's idea of using a thread of cover for that is a good one - high strength is not needed there). No one seems to do that before lock stitching and I think it would be beneficial.

Stretching before stitching is a good idea, especially if one stitches a long segment, or over the whole crossover point (from C to C'). Both long and short stitching were used in the referenced methods.

It would make sense also to address stitching and stretching of the buried segment of the crossover point vs. the whole finished splice separately.

I very much doubt all 11 lots of these eye splicing are equal. The easiest take shortcuts that I think will ultimately affect eye splice performance or that of the line adjacent to it. The most difficult to follow (for me that was the Sailrite video) are not necessarily the best either.

Anyway, these thoughts are all still milling around. I will sleep on it and look at the methods again next week.

Some discussion here would be very useful.

SWL

[Juho]

Originally Posted by Juho

Note that also in some more traditional splices the tail of the cover is not buried very deep

I should have written "core" instead of "cover".

[s/v Jedi]

Originally Posted by Seaworthy Lass

Biggest problem I can see is that nothing is gripping the end of the core well any longer, so line strength will become cover strength.

If the core is somehow gripped, as far as I understand, the proposal is based on the assumption that the cover is responsible for 50% of the strength of the rope. I am not sure that is correct, but if it is, this is likely to apply only to brand new rope. As soon as it is exposed to UV and chafe (likely at the peak of the eye unless you were adding a thimble) the breaking strain would decrease and fall below line strength.

I'm not sure I follow you. The line strength (line + eye splice) will be twice the cover strength, because the cover is spliced and the load spreads over both legs of the eye. As confirmed by splicing instructions (Selma?) this means the splice is as strong as the rope.

The second part I follow again and I agree that the cover will de-rate more than the core by aging when in use.

I believe that for every possible splice, when done right and without damaging any fibers, point E is the weak point. I.e. from the standing part of the line, approaching the eye splice, the first extra cover-fiber from the splice is the cause for a break at or near that point. Data from testing seems to agree with that.

Everything beyond point E into the splice is stronger than the rope it's made from.

[Seaworthy Lass]

Originally Posted by s/v Jedi

I'm not sure I follow you. The line strength (line + eye splice) will be twice the cover strength, because the cover is spliced and the load spreads over both legs of the eye. As confirmed by splicing instructions (Selma?) this means the splice is as strong as the rope.

Hi Jedi
As far as I understand, the purpose of Juho's "extreme" splice model is to create a splice that basically maintains line strength while being as thin as possible.

This is how I understand the ”extreme" model:

The core is being cut at the base of the eye and is tapered starting just below this at the crossover point.
The cover is tapered as well:




Firstly, doubling the cover in the loop will only give line strength if the cover strength is 50% of line strength to start with. This is not universal.

Secondly, line strength is maintained in the line below the splice only if the core is being gripped. If it lets go in the spliced portion, then you are down to cover strength alone. What is gripping the tapered core in the splice well under load?
I don't think the proposed line of stitching would be adequate holding a tapered core.

SWL

[Juho]

Originally Posted by Seaworthy Lass

What is gripping the tapered core in the splice well under load?
I don't think the proposed line of stitching would be adequate holding a tapered core.

I proposed to have a very long buried core as one possible solution, and the stitching could be much longer, covering all of the buried core. I guess you can reach sufficient strength (close to 100% of the original rope strength) by doing these tricks. It is possible that a thin slice has some strength due to not being stretched like a bulky splice.

The strength of the loop (that consisted only of an empty cover, and may be bend sharply is suitable circumstances) is another possible risk (in addition to the already mentioned UV and wearing problems of a rope with lots of surface area in proportion to inner material).

[s/v Jedi]

Originally Posted by Seaworthy Lass

Hi Jedi
As far as I understand, the purpose of Juho's "extreme" splice model is to create a splice that basically maintains line strength while being as thin as possible.

This is how I understand the ”extreme" model:

The core is being cut at the base of the eye and is tapered starting just below this at the crossover point.
The cover is tapered as well:




Firstly, doubling the cover in the loop will only give line strength if the cover strength is 50% of line strength to start with. This is not universal.

Secondly, line strength is maintained in the line below the splice only if the core is being gripped. If it lets go in the spliced portion, then you are down to cover strength alone. What is gripping the tapered core in the splice well under load?
I don't think the proposed line of stitching would be adequate holding a tapered core.

SWL

Let's say the core ends halfway the eye without being spliced at all. My position is that the line before the eye splice maintains it's strength even under that condition, just like when it does without any splice at all. This is why double braid works, the outer braid squeezes the core over the entire length, locking it in place every millimeter all the way.

This is why I think you see this wrong and are too much focused on the actual splice rather than where during tests the failures occur. It doesn't break just in front of an eye splice because the core isn't spliced. It does because fibers are crushed or some are tighter than others in such a way that a couple of fibers break, which puts more load on the remaining fibers causing an avalange effect leading to total failure.

[Seaworthy Lass]

Originally Posted by s/v Jedi

This is why I think you see this wrong and are too much focused on the actual splice rather than where during tests the failures occur. It doesn't break just in front of an eye splice because the core isn't spliced. It does because fibers are crushed or some are tighter than others in such a way that a couple of fibers break, which puts more load on the remaining fibers causing an avalange effect leading to total failure.

Just the opposite . I am not focussed on the splice itself (check out post #8 in this thread). Other splice issues such as tapering have just come up incidentally during discussion. There is room for all sorts of improvement, but I am focussed primarily on the effect of cutting excessive core off, as many techniques casually seem to do.

My theory is that when too much core is cut off, the relationship between the core and cover is disrupted. The portion of line likely to be affected is right next to the splice, as the cover has been vigorously bunched up here to try and milk the splice into position. The bunching may not equalise along the length of the line. If not, line strength is affected in this area and so this is where splices are likely to break. As far as I understand, this is actually where they do break.

I think splicing technique can minimise this problem. Along the way, other aspects of splicing can also be improved on.

In practice eye splices do break in double braid polyester. And not uncommonly. I have suffered the consequences a few times as crew. Suffered, as I am generally the lightest on board and sent up the mast to fix things .

All techniques are not equal. They vary wildly with some parameters.
Some, like the instructions given with Selma fids, go back over half a century and have not be updated. At least we can try and estimate which technique it would be best to follow.

SWL

[Seaworthy Lass]

One more method to add:

English Braids:

YouTube user: EnglishBraids
Published on Apr 4, 2014
"English Braids is looking to deliver the best possible support for all yachtsmen looking to maintain their own products. This video clearly demonstrates the technique required to perform a braid on braid splice. The load is shared between the core and the cover and it is important to note that this differs from a Dyneema Splice although sometimes it can be completed."

https://www.youtube.com/watch?v=wRJxjl8Brtg&sns=em

Jedi, any more to contribute?
Your additions have been very useful. Thanks

SWL

[Seaworthy Lass]

The table comparing methods used for eye splicing double braid Class 1 rope is growing like Topsy .

12 techniques have been included so far.
Anyone with more to add? The list is in post #119, plus English Braid.

They all start with a fid length of cover tail being marked for bury.
They all tell you to mark whatever eye size you desire.
From then on, they all do their own thing.

Some of the measurements are wildly different.
Techniques vary tremendously for some aspects eg for initial milking and final tapering.
It is quite fascinating seeing the differences.

So, the burning question is: which is the best method?

Although no studies have been done that I am aware of comparing the strength of the methods, research has been done on characteristics of rope that should help us gauge which technique may be best.

Alan Mighty is coordinating this project. Juho and I are contributing. Jedi has added lots of helpful posts. Input from everyone is welcome and would be very appreciated.

Stay tuned.

SWL

[s/v Jedi]

Well, for a somewhat different angle we could consider this German splice from Gleistein Ropes

https://www.youtube.com/watch?v=IstdZZXL3UI

[s/v Jedi]

And here is another good test video that shows the break occurs in the typical spot just in front of the splice, which is considered the weakest spot of the line:

https://www.youtube.com/watch?v=bLZUfPZbU3s