dyneema loop with low friction ring construction

[ID_girl]

Hi all,

New member here with a question about the construction of the Low Friction Ring on a Dyneema loop.

For a winter time project, I've decided to learn to splice Dyneema lines working up to making soft-shackles and my own low-friction rings with the dyneema loops.

e.g. http://www.antal.it/ENG/rl40_ring__loop_en

Can someone explain to me how these are made? Is a continuous loop first made and then seized using dyneema whipping twine to secure the ring?

Thanks for your help and for letting me join.

Christine

 

[estarzinger]

there are simple and complicated ways to make these.

The simplest is as you describe - a loop and whipped.



Still simple, but slightly more complex is to work a tuck or brummel into the loop



More complicated are to do it all 'spliced' and not depending on a whipping - this picture will give you an idea of one approach for that.



The 'problem' with the two simplest approaches is that they usually (as in your pic) have very tight (eg less than 2:1) throat angles, which decrease their strength (by very very roughly 20%). If the dyneema is well over spec (as it usually is) that is no problem. The whipping I pic above (first pic) is carefully designed to have an 'open' throat angle to avoid this.

Probably the most pro way to make them is with a multi-pass loop - like a custom yale LOOP's fit/locked onto the ring. It's not hard to do, but a bit more work to get all neat and with all the legs sharing the load evenly.

So there are many ways to accomplish this - and if your dyneema is oversized they will all work just fine, some just a bit more 'proper' than others.

 

[ID_girl]

Wow,

Thanks for the informative reply to my question.

In order to make sure I understand your suggestions I looked at your website (very informative too!) and searched for the following online: "constrictor splice" and "yale loop" splice. Unfortunately I could not find any other references to these that applied to the hollow braid dyneema type rope. Do you have a suggestion for a book or other reference that would help me with these?

Finally, after the constrictor splice is made around the ring, instead of finishing it with a bury splice and making an eye splice on the end of the end of the remaining line (http://www.neropes.com/Splicing%20Guide%20Individual%20Splices/Single_Braid%20Eye_Splice%20_Brummell.pdf), could the line from one side be passed through the other to achieve the desired throat angle and then join the two ends with an end-to-end splice? (http://www.neropes.com/Splicing%20Guide%20Individual%20Splices/12_Strand_Single_Braid_End_For_End_Bury.pdf)

Thanks for your help,

Christine

 

[estarzinger]

Wow,

Thanks for the informative reply to my question.

In order to make sure I understand your suggestions I looked at your website (very informative too!) and searched for the following online: "constrictor splice" and "yale loop" splice. Unfortunately I could not find any other references to these that applied to the hollow braid dyneema type rope. Do you have a suggestion for a book or other reference that would help me with these?

Finally, after the constrictor splice is made around the ring, instead of finishing it with a bury splice and making an eye splice on the end of the end of the remaining line (http://www.neropes.com/Splicing%20Guide%20Individual%20Splices/Single_Braid%20Eye_Splice%20_Brummell.pdf), could the line from one side be passed through the other to achieve the desired throat angle and then join the two ends with an end-to-end splice? (http://www.neropes.com/Splicing%20Guide%20Individual%20Splices/12_Strand_Single_Braid_End_For_End_Bury.pdf)

Thanks for your help,

Christine

First, I am not aware of any specific good public instructions for doing the 'more proper' techniques on a ring. And I have discovered I am no good at all at writing or photoing instructions - we need either allen or brion to do some up as they are both good at it.

What I can tell you:

As to the bottom photo - constrictor style - I think that particular technique was invented by rule69 on SA, at least I first saw him doing it - it's simple. you take the dyneema around the ring, and where they meet you insert one end into the hollow center of the other piece and thread it again right around the ring still in the hollow center, and pull it out of the center just a little ways before it meets itself. and then do an end to end splice to complete the loop.

As to the Yale loops (licensed to harken), it is just a multi-leg loop (one long loop folded down into multiple loops), with an end to end splice, with a cover. This has two advantages - allows a full length bury in the end to end splice, when a single leg loop would not be long enough to AND it reduces the load on that splice. There are videos on how to do this - there was another thread relatively recently. In the case of making one specifically to capture a ring - there are again a number of ways to do it. I think the one I have seen most commonly is to have one leg exit the cover, cross to the other cover, and go around the ring - that traps the ring (so you visualize a multi leg loop, with one of the legs just around the ring, while all the others are 'full length').

As to your last comment/suggestion -yes, that is certainly a reasonable technique. You might need a little bit of sewing or whipping to get the 2:1 throat angle plus a secure ring capture. I do think the constrictor style is a 'better' approach' - but again, they will mostly all work just fine.

Quite honestly, if you just made up an end to end loop, and clove hitched it around the ring - you would most likely be just fine.

 

[ID_girl]

Once again, Thanks. This is the information I was hoping to learn. Perhaps I am going overboard with the details but if nothing else, I am learning quite a bit.

Fair Winds,

Christine

 

[Schnick]

Pet peeve with these: The loop that you use to attach to (whatever) is always too long. In a few places this is no big deal, but if you use them on, say, the spinnaker guy, which is a great application for a low friction ring, you give up about 4-6" of leverage when reaching with the pole forward. I have more often ended up just lashing them in place so that I can lash them tight down to whatever fitting I'm working with.

 

[Alex W]

I've made short ones to handle Schnick's concern by putting a constrictor splice that goes around the ring into the middle of a soft shackle. You can make a much shorter soft shackle than you can a loop. I can dig up a photo later if the description isn't clear.

 

[Training Wheels]

Does it weaken a low friction ring if you attach it by putting a soft shackle through the middle of the ring, and run the line also through the middle?

 

[StumbleNola]

Does it weaken a low friction ring if you attach it by putting a soft shackle through the middle of the ring, and run the line also through the middle?

Not really. Or at least not enough to matter. These things are so massively strong the real issue would be the lines running on each other not the strength of the ring.

 

[Christian]

Does it weaken a low friction ring if you attach it by putting a soft shackle through the middle of the ring, and run the line also through the middle?

Not really. Or at least not enough to matter. These things are so massively strong the real issue would be the lines running on each other not the strength of the ring.

Certainly depends on the load - so your statement is maybe a bit too quick..............

 

[StumbleNola]

Does it weaken a low friction ring if you attach it by putting a soft shackle through the middle of the ring, and run the line also through the middle?

Not really. Or at least not enough to matter. These things are so massively strong the real issue would be the lines running on each other not the strength of the ring.

Certainly depends on the load - so your statement is maybe a bit too quick..............

Oh sure you can break them, but it isn't likely.
The ronstan 5mm ring (inner dimension) has a swl of 500kg. If you pass two lines thru the ring the largest size you could possibly use without them rubbing would be 2.5mm dyneema with a MBL of 650kg. It is just possible that the ring would break before the ring, but I doubt it, the rings actual MBL isnt published, but it must have some safety factor built in.

If you step up to the ronstan 11mm ring with a swl of 2000kg, you could go to two passes of 5mm amsteel with a MBL 2200kg and again it might be possible, to break the ring but I doubt it.

This pattern hold true up to the 26mm ring with a swl of 7,000kg while 12mm dyneema has a MBL of 13,900kg. This is the first point at which the line strength is substantially larger than the swl of the rings.

Basically until you get to massive loads the rings are as strong as the line passing thru it, and so it is more likely that the line breaks than the ring. Now if you use the largest size line possible to pass they the center hole then it is possible to overload them, but it would still take a very highly loaded line.

http://www.ronstan.com/marine/range.asp?RnID=428

 

[estarzinger]

If you want a shorter loop - simplest way is you can make a longer loop (so you still have proper bury) of smaller diameter dyneema, and then double it over (so it is half length with two circles), put over ring and whip/sew in place. If the multiple loops bother you - you can put them in a cover together or sew them together., or just tape together.

You can make this arbitrarily short, by doubling (forming extra loops) it as many times as you want. It is generally nor recommended to do it more than 4 doubles (so 8 legs) because beyond that the legs start to carry uneven loading. BTW, in practice, if you double a line into 4 loops, you can join the ends with a 5 brummel rather than use the much longer bury splice - it will only be carrying 1/8 the load so the fact it is a bit weaker does not make much difference. You could even use a bend*, which is weaker yet (and can theoretically slip), but with 4 loops is unlikily to make much difference - it is a bit bulkier though.

* some of you will remember from our very long dyneema thread that bends are 'difficult' in bare dyneema. Almost all the common ones slip at relatively low load, even the much touted triple fisherman. There are two adequate but not commonly known solutions (1) tie two EStar loops together - loop to loop. This will be secure, strong and low profile (looks similar to a fisherman when done). (2) An alternative is to use the eye structures (of the non-slipping loop knots - water bowline or figure 8 loop), but make the first part of whatever eye on each line and then the knots are completed with each other's tails (end-A with end-B's, ...). That will equal the non-slip performance and strength of the eyes alone, but with out the chafe and 1:1 bend radius of interlocked loops. But they are not so compact as the back to back estar's.These are shown and described on my load testing page.

A lashing also works as mentioned and can be made arbitrarily short.

You can also use a soft shackle around the outside - just whip or sew it in place.

As to the loop going thru the hole vs around the outside . . .there are two issues making around the outside prefered;

#1 if you go around the outside with the loop you can use larger line, because they are not fighting for the same space.

#2 if you go around the outside with the loop the loaded line is pulling on the loop, which is strongest possible configuration; while if you go thru the middle with the loop, the loaded line and loop are essentially pulling the aluminum ring apart - this is definitely weaker - but as mentioned above still strong enough for many applications - but you will rarely see a 'pro' do it that way.

 

[IStream]

Evans, did you mean to say "2 doubles (so 8 legs)" above? No doubles = 2 legs, one double = 4 legs, two doubles = 8 legs.

 

[RImike]

If you want a shorter loop - simplest way is you can make a longer loop (so you still have proper bury) of smaller diameter dyneema, and then double it over (so it is half length with two circles), put over ring and whip/sew in place. If the multiple loops bother you - you can put them in a cover together or sew them together., or just tape together.

You can make this arbitrarily short, by doubling (forming extra loops) it as many times as you want. It is generally nor recommended to do it more than 4 doubles (so 8 legs) because beyond that the legs start to carry uneven loading. BTW, in practice, if you double a line into 4 loops, you can join the ends with a 5 brummel rather than use the much longer bury splice - it will only be carrying 1/8 the load so the fact it is a bit weaker does not make much difference. You could even use a bend*, which is weaker yet (and can theoretically slip), but with 4 loops is unlikily to make much difference - it is a bit bulkier though.

* some of you will remember from our very long dyneema thread that bends are 'difficult' in bare dyneema. Almost all the common ones slip at relatively low load, even the much touted triple fisherman. There are two adequate but not commonly known solutions (1) tie two EStar loops together - loop to loop. This will be secure, strong and low profile (looks similar to a fisherman when done). (2) An alternative is to use the eye structures (of the non-slipping loop knots - water bowline or figure 8 loop), but make the first part of whatever eye on each line and then the knots are completed with each other's tails (end-A with end-B's, ...). That will equal the non-slip performance and strength of the eyes alone, but with out the chafe and 1:1 bend radius of interlocked loops. But they are not so compact as the back to back estar's.These are shown and described on my load testing page.

A lashing also works as mentioned and can be made arbitrarily short.

You can also use a soft shackle around the outside - just whip or sew it in place.

As to the loop going thru the hole vs around the outside . . .there are two issues making around the outside prefered;

#1 if you go around the outside with the loop you can use larger line, because they are not fighting for the same space.

#2 if you go around the outside with the loop the loaded line is pulling on the loop, which is strongest possible configuration; while if you go thru the middle with the loop, the loaded line and loop are essentially pulling the aluminum ring apart - this is definitely weaker - but as mentioned above still strong enough for many applications - but you will rarely see a 'pro' do it that way.

I've done this method before to get the low friction ring closest to the attachment point as necessary. Just remember that when you do this method, the line passes over the ring 4 times total, twice when you make the continuous loop and a second time when both ends of the loop pass over the ring. I had to jump up to the R10.07, even though I only needed the 7.05 for the vang cascade.

It's hard to see but if you look in the lower left near the mast partner you can see what I am referring too:

 

[estarzinger]

Evans, did you mean to say "2 doubles (so 8 legs)" above? No doubles = 2 legs, one double = 4 legs, two doubles = 8 legs.

It is a point of undefined nomenclature.What you are saying probably makes more logical linguistic sense. I was just using the term 'double' to mean adding another loop, with 2 more legs, rather than the way you are to mean doubling the number of loops.

In any case, the important point, is that generally 8 legs is (generally) about where you want to stop (unless you do some careful load balancing process), so that the legs share the load evenly and don't get out of balance.

I've done this method before to get the low friction ring closest to the attachment point as necessary. Just remember that when you do this method, the line passes over the ring 4 times total, twice when you make the continuous loop and a second time when both ends of the loop pass over the ring. I had to jump up to the R10.07, even though I only needed the 7.05 for the vang cascade.

It's hard to see but if you look in the lower left near the mast partner you can see what I am referring too:

nice work - you have obviously been using the full dyneema playbook Any practical feedback on things that did not work the way you expected or hoped?

 

[RImike]

Evans, did you mean to say "2 doubles (so 8 legs)" above? No doubles = 2 legs, one double = 4 legs, two doubles = 8 legs.

It is a point of undefined nomenclature.What you are saying probably makes more logical linguistic sense. I was just using the term 'double' to mean adding another loop, with 2 more legs, rather than the way you are to mean doubling the number of loops.

In any case, the important point, is that generally 8 legs is (generally) about where you want to stop (unless you do some careful load balancing process), so that the legs share the load evenly and don't get out of balance.

I've done this method before to get the low friction ring closest to the attachment point as necessary. Just remember that when you do this method, the line passes over the ring 4 times total, twice when you make the continuous loop and a second time when both ends of the loop pass over the ring. I had to jump up to the R10.07, even though I only needed the 7.05 for the vang cascade.

It's hard to see but if you look in the lower left near the mast partner you can see what I am referring too:

nice work - you have obviously been using the full dyneema playbook Any practical feedback on things that did not work the way you expected or hoped?

IMG_2125.jpg

The only thing that I would say is that I measured everything the two attachment points in the winter and mocked it up using 2X4's in my basement during last winter. I then built it off that. I never realized however that even though I used 3mm D12 max, the constructional stretch as the splices as they set and the whole system lenghtened. Needless to say that after the first sail, where the cross over was between the cover and core for the final end of the cascade was about 3 inches past the cleat so I had to re-splice and shorten each leg. Now I have it tuned properly so the cross over stays between the low friction ring and the fair lead for the cam cleat. Also when blowing 30 out, I can still pull it just as easily as I did when it was blocks. Mind you we don't reef (30' Shields) :blink: and nothing has exploded in my face yet, good stuff

 

[SockeyeUS119]

I thought that looked a little familiar. The Saga is at our docks. Those cute little mini 6's.

 

[olsen370]

Instead of using the classic low friction rings I recommend this friction ring.

http://greement-courant.fr/blog/nub-the-revolutionary-friction-block/

 

[Max Rockatansky]

Anyone selling those NUBs in the States?