reserve closing loop fingertraps

[tsalnukt 1]

I was always taught that when you make a closing loop you need to make the knot so that it includes the fingertrap. I have come across a few reserve closing loops that aren't that way. The loop is fingertrapped a few inches down to make the loop and then going through the disc and the knot is just "single layer" of cypress line. Is this "ok"? I know fingertraps are strong but I also have seem them slip. Should I go tell this other rigger to bring it to his attention or is this ok to do???? thanks for your help

[riggerrob 558]

That's odd!
I have never seen that before.

A single layer through the washer guarantees that it will break at the washer.
Far better to have a double layer going through the washer.

[erdnarob 1]

In my opinion it is not right. The fingertrap has to be full length of the closing loop and the knot obviously has to involve the fingertrap (2 loops) to make sure everything is locked. If you look at the prepared closing loops when you buy a Cypres rigger kit, you will see that the closing loops are full lenght fingertrapped, same for a rigger's kit from Vigil. A fingertrap theoretically is strong enough to not slip when pull force is applied. More you pull and more the outside loop of the fingertrap chokes the inside one and lock it. But it has to be double (full length fingertrapped) for more strength. As I said in another thread, the closing loop from Cypres is rated at 180 kilograms or 398 lbs. When full length fingertraped that makes a tensile strenght of about 800 lbs. I think I know why some rigger use that wrong method, it is easier to thread the loop thru the little holes of the Cypres washer. Personnaly I make my fingertrap full length with just the inside loop half a inch shorter. The outside a bit longer loop is then easier to go thru the holes and squeeze the inside loop when both has to go thru but I always make sure that the knots catch the two fingertraped loops. I start now using the Vigil Dyneema braid provided for closing loop. It is similar to the Cypres one but the big difference is the Vigil washer which is in stainless steel and has one hole and 2 slots and found it way easier to deal with. The double knot plus the stop knot bulk is stopped by the loop itself. See on Vigil wen site.

Learn from others mistakes, you will never live long enough to make them all.

[rhys 0]

That sounds potentially dangerous to me, i am a rookie reserve packer but this is one thng that was made clear to me.

full length finger traps on all closing loops!

sounds like someone needs a talking to.

"When the power of love overcomes the love of power, then the world will see peace." - 'Jimi' Hendrix

[980 0]

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As I said in another thread, the closing loop from Cypres is rated at 180 kilograms or 398 lbs.
When full length fingertraped that makes a tensile strenght of about 800 lbs.

Airtec seems to differ with you on that.

Here they specify 450lbs for the breaking strength of a loop and anyone who has ever broken one with a leverage device would agree that 800lbs is a ridiculous number.

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I think I know why some rigger use that wrong method, it is easier to thread the loop thru the little holes of the Cypres washer. Personnaly I make my fingertrap full length with just the inside loop half a inch shorter.

Your method uses a loop that is different to the Airtec supplied one, so I would suggest this means your method is not correct either.

Try making the loop like Airtec does, with the inside line sticking out from the outside line or equal at the end.

Then use a length of seal thread (the same length you need to seal the container works great) as a pull-up cord to thread the loop through washer, loop side first.

After you have then stretched and knotted the loop to the correct length, you can trim the excess tail down to 2" or so.

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I start now using the Vigil Dyneema braid provided for closing loop. It is similar to the Cypres one but the big difference is the Vigil washer which is in stainless steel and has one hole and 2 slots and found it way easier to deal with.

Do you use this on Cypres equipped rigs? Is it approved for such use?

[peek 20]

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I was always taught that when you make a closing loop you need to make the knot so that it includes the fingertrap. I have come across a few reserve closing loops that aren't that way.

You were taught well.

It's so disheartening to hear of such things :(

I would be interested in knowing what the "designer" of this loop trying to accomplish, saving a few inches of loop material?

[erdnarob 1]

When I said the Cypres braid was rated at approximately 180 kilograms, that comes right out the Cypres manual page 34. Since 180 kilograms make 396.8 lbs, when doubled that makes 793.6 lbs since it is fingertraped and therefore almost 800 lbs. Sorry but mathematics are clear about it and there is nothing ridiculous here.
However I agree that the fingertrap loop can break before 800 lbs since it is pinched and squeezed between grommets making that way weak points in it.

OTOH when I make the Cypres loop with the inside braid slightly shorter (half an inch), it's to put it more easily thru the washer holes. But read well my post, I make sure the knots are done on the fingertrap catching that way the outside and inside braids where it counts and locking them together, the remaining part of the braid opposite to the loop past the knots has no function at all, all right? Therefore your remark is somehow a bit awkward.

Learn from others mistakes, you will never live long enough to make them all.

[erdnarob 1]

Garry, a lot of people are not using their own judgement especially about what is the functionality of what they do. Making the knots on the fingertrap of a closing loop and therefore locking the braids (inside and outside) together seems obvious but not for people who do not use their brain. Reading a manual is great but you still have to get a good interpretation of it. I would suggest that Airtec makes it clear in its manual that the knots have to comprise the two fingertraped loops.

Try to make a system foolproof and there will always be a smart who will find a way to f..ked it up.

Learn from others mistakes, you will never live long enough to make them all.

[tsalnukt 1]

the fingertrapped part of the loop should be 800 pounds or so but remember.....the loop isn't fingertrapped. The actual loop part is only a single piece of cypress loop.

[erdnarob 1]

Physics, physics... the loop around the pin acts like a rope going around a single pulley therefore the force is divided by 2 because of the 2 parts of the loop. Demo: Have a rope long enough with the 2 ends attached at the ceiling and put a single pulley (with a hook) where the rope has a curve below (rope going around the pulley), Then suspend a weight of 800 lbs to the pulley hook. You will have 400 lbs per branch since there is 2 branches. Actually, since the closing loop is pinched, there is a weak point at the pin which reduces the actual strength at that very location. The loop going thru the little ring of the 3 ring release acts like a single pulley the same way, it divides the force by 2 where it is attached. Tell me if it's clear enough otherwise I will make a sketch.

Learn from others mistakes, you will never live long enough to make them all.

[pchapman 261]

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loop from Cypres is rated at 180 kilograms or 398 lbs.
When full length fingertraped that makes a tensile strenght of about 800 lbs.

Airtec seems to differ with you on that.
[...] Here they specify 450lbs for the breaking strength of a loop and

Hi Sam and Andre,

I thought I knew the answer but now I'm not sure!

Sounds like confusion over the strength of a completed loop vs. that of the material itself.

The Cypres 2 manual mentions 450 lbs for a Cypres LOOP (and shows a photo of a completed loop) -- which is basically what 980's link shows.

My spool of Cypres material says "185 kp" on it, i.e. kilopond or kilograms-force. That would suggest the 400-450 lbs value is for the MATERIAL.

The Cypres Rigger's Manual mentions the MATERIAL: "Cypres loops are made from polyamide nylon cord and are specifically designed for
use with the system. This is an innovative, very thin material with a diameter of
1.8mm and a breaking strain of approximately 180kp. "

It sure does seem that it takes less than 800 lbs to break a loop, but I haven't calculated the numbers a novice rigger might apply on a torquing device. And loops only seem to break at their apex so I think there's the issue of thin cord slicing through thin cord with a tight bend radius, that is reducing the strength factor. Don't know how much.

I'm tending to believe that the material is ~400 lbs, so the full loop is ~800 in the ideal world, but Cypres sure isn't very clear in their writing...

[erdnarob 1]

I agree with you that there might be a confusion. Cypres loop however are made from Polyethylene (page 34 of Cypres owner's guide) fiber like the Spectra line and not made of nylon. As I mentioned it there is a weak point when the loop is squeezed at the pin and the loop will likely break there. In am pretty sure that if the diameter of the pin would be bigger like it is on the Skyhook) the breaking point would be higher. Maybe Cypres when telling that the maximum strength of a alerady made loop is 450 lbs consider the safety factor. I will tried to get that clear by performing my own experiment.

Learn from others mistakes, you will never live long enough to make them all.

[hackish 8]

I do it similar to Andre - pull the inner braid about 1/4" in after I cut it. The outer braid fits in the washer nicely. Of course both are included in the knot as about 1.5" of excess are cut off after the knots are tied. I have also tried rubbing the cut end on some beeswax so the strands stay together and can be threaded through the hole - that works too.

I assume the sealing thread trick is used to pull it in from the loop end? going to try that next time I get a chance.

-Michael

[tsalnukt 1]

Super-tack also works well to pull the loop end through the washer as well.

[Unstable 8]

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You were taught well.

It's so disheartening to hear of such things :(

I would be interested in knowing what the "designer" of this loop trying to accomplish, saving a few inches of loop material?

Agreed. This is a sloopy job on rigging and stuff like that suprises me. Poynters says that a fingertrap needs to be at least 4" long to be self-sustaining, and I can think of lots of closing loops I've made that were less tha that. If the designer applied his 'trick' to smaller rigs, then that strikes me as a major safety concern.

=========Shaun ==========

[erdnarob 1]

I know that the following is not directly related to the thread but since we are talking about reserve closing loop , here is a simple way to use in order to get the closing loop less damaged when closing the reserve container. Instead of using one pull cord (made from the same material than the loop) I use two. I got this trick from the Vector III DVD explaining how to pack a main and a reserve in a Vector container. When you have to thread the 4 strings of the 2 pull cords thru the cutter hole if any, just wet the ends and twist them together and when you put this twist in the hole keep on twisting the right way (opposite way with respect to the pull cord twist). Beside that there no difference using two pull cords. The idea to use two pull cords is that the surface between the 2 pull cords and the closing loop is doubled threefore there is less pressure on the closing loop then less damage.

Learn from others mistakes, you will never live long enough to make them all.

[tsalnukt 1]

Is there any harm in using diffrent material?? Why not just use a thicker line??? Of course, you would have trouble getting thicker stuff through a cutter. besides that is there anything wrong with it?

[mjosparky 3]

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Is there any harm in using diffrent material?? Why not just use a thicker line??? Of course, you would have trouble getting thicker stuff through a cutter. besides that is there anything wrong with it?

Yes, it goes against manufactures instructions for both the rig and the AAD.

Sparky

My idea of a fair fight is clubbing baby seals

[jumper03 0]

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I know that the following is not directly related to the thread but since we are talking about reserve closing loop , here is a simple way to use in order to get the closing loop less damaged when closing the reserve container. Instead of using one pull cord (made from the same material than the loop) I use two. I got this trick from the Vector III DVD explaining how to pack a main and a reserve in a Vector container. When you have to thread the 4 strings of the 2 pull cords thru the cutter hole if any, just wet the ends and twist them together and when you put this twist in the hole keep on twisting the right way (opposite way with respect to the pull cord twist). Beside that there no difference using two pull cords. The idea to use two pull cords is that the surface between the 2 pull cords and the closing loop is doubled threefore there is less pressure on the closing loop then less damage.

Instead of all that, I made a 'guppy' cord. Just put a 4 inch length of cypres cord into middle of the pull up cord. Accomplishes the same thing.

Scars remind us that the past is real

[mjosparky 3]

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Instead of all that, I made a 'guppy' cord. Just put a 4 inch length of cypres cord into middle of the pull up cord. Accomplishes the same thing.

No more calls, we have a winner. A trick as old as rigging. Never heard it called a "guppy" cord but that will do.

Sparky

My idea of a fair fight is clubbing baby seals

[JerryBaumchen 1,049]

Hi Sparky,

Well, I have never heard of it called a 'guppy' cord but it is what I've been doing for years.

Guess we have a new term in this whole rigging thingy.

Pop quiz Friday folks,

JerryBaumchen

[jumper03 0]

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Instead of all that, I made a 'guppy' cord. Just put a 4 inch length of cypres cord into middle of the pull up cord. Accomplishes the same thing.

No more calls, we have a winner. A trick as old as rigging. Never heard it called a "guppy" cord but that will do.

Sparky

Wish I could take credit for the name but I got it from Old man Greg at the GB club.

He would probably be glad to tell you the story of where the name came from - or any other story he can think up...

Scars remind us that the past is real

[Canadianfella 0]

so you fingertrap a 4" piece into the middle of it so it's thicker/stronger in the center where you'd normally be pulling from? did i read that right?

[jumper03 0]

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so you fingertrap a 4" piece into the middle of it so it's thicker/stronger in the center where you'd normally be pulling from? did i read that right?

Yes - in the center where the pull up cord goes through the closing loop. Makes getting the pin in much easier as the larger cord keeps the two sides of the closing loop further apart. I will take a picture of mine when I get back to the loft.

Scars remind us that the past is real

[erdnarob 1]

Spectra is made of polyethylene fiber and has a higher tensile strength than nylon fiber. That's why we generally use the same kind of material for a pull cord. Using a 550 lbs sheating as a pull cord on a Spectra loop is OK, it's just a bit thicker than 2 pull cords made of spectra/cypres line. Expect the stronger one (the Spectra) to "eat" the softer one. Also when using the Spectra/Cypres pull cord, at the end you can remove them one at a time wich is softer on the closing loop.

Learn from others mistakes, you will never live long enough to make them all.