rock exotica

quercus

Guys , I have a problem...

I've seen a very interesting piece of equipment from rock exotica. It's called the dualcender.The design is exactly the same as Petzl's ascenders, but for double rope.I think it would be great for footlocking and I think it's in sherrill's catalogue but like I said... there's a problem. Because of the fact that it's not CE certified (the european standard for PPE) they won't send it to Belgium. I've asked several tree gear company's around here but they won't order or sell it, wich is normal due to restrictions on testing and CE standards.
I'm looking for someone in the US or somewhere else who can order it for me and send it to me... I'll pay up front of course.
can someone help me?

Done it

Hi Quercus,
There are a few mail forwarding sites where you can buy items in US. They supply an address then forward them to you. Some are a bit dodgy but this one is safe. It might seem a bit expensive to set up but with what you save it works well.Access USA - The Leader In Package Forwarding Hope that worked I haven't done it before.

ronnyb

Have you ever tried a handled ascender? I use a Kong double ascender. The handgrips really help. I'm 40 years old, so I'll take any advantage I can get. PM me in you want either the exotica or whatever.

George Hayduke

Kong products, especially the double cammed handle ascenders should be used with extreme care. There are plenty of great products, don't use inferior gear.

Tree Machine

I don't think George is implying that the Kong dualcenders are inferior.

Maybe, though. What's clear is 'don't buy inferior gear'. Well, of course.


All climbing gear, including ascenders should be used with extreme care.



George, who has better dual-handled ascenders? As Ronny B says, having the handle gives a climber an advantage. Additionally they don't have to be disassembled to put them on and take them off and one side can be used independently of the other. These are also advantages, not in the dualscenders, though.

I will use the dualscenders as backup to the Kongs, but would only use the dualcender as a sole ascender if it were the only option. This is not a personal preference. We use the safest gear that will offer is the most in performance.

A simple captive bar is missing for the Kong Duals. I have written Kong about a couple improvements, they have only incorporated one, a couple years ago. The other improvement can be created here at our end for about a dollar, a piece available from any hardware store.

Still, the improvements could be created at the Italy end and it would be nice if they did.

George Hayduke

Maybe I'm being too PC...the Kong dual ascenders have failed MANY time leading to injuries. They are dangerous.

Check for yourself, but I think that Kong has stopped making them. Good!

Shift to using single rope like the rest of the rope access world and things get sooo simple! Lots of great options for gear and backups are way better.

ronnyb

Never seen or heard of a kong failing, you're supposed to use a backup with any ascender any ways. Matter of fact, I was introduced to the Kong at ArborMaster.

reachtreeservice

Some accidents have occurred and are documented. Causes include one leg of the rope being pushed out of the cam because the climber placed the ascender too close to the tie in point, climbers accidentally releasing the cam with their thumbs, tree debris preventing the cam from properly closing, etc...

Even placing a keychain biner behind the cams, the climber can still accidentally release the cam with their thumb or debris can prevent the cam from engaging properly.

The kong should always be backed up. The best back up is a bow shackle placed in the hole above the cams. A piece of 3/8 tenex is spliced to the bow shackle so that there are two equal lengths coming off the shackle. One leg is tied with a friction hitch ( I use a Distal ) to each leg of the doubled climbing rope.

Credit for the above technique and info goes to Mark Adams, Instructor for North American Training Solutions. It was first published in the Climbers corner of I.S.A.'s Arborist News some time ago.

reachtreeservice

I agree that SRT is almost always the best method of canopy access.

newguy18

Its alright for heights above 70' but any lower I perfer drt.

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old schooler

quercus

I use double cammed ascenders too but I made one myself using two ascensions (left and right) from Petzl. I cut the rubber handles off, screwed them together using holes that are originally in the device (so no drilling) and secured the bolts with loc-tite, then I cut the handles very accurate in two seperate parts (again one left and one right part). I glued the handles back on on each side and secured them with a very strong vinyl based tape. In this system you can't use a carabiner anymore to lock the rope in because the device is too wide. So at first I used a smooth nut and bolt. Because it was a bit too bulky I switched to a 10 mm rope with stopper knots. When I use this device I climb for a meter or two and place a figure 8 knot on the two ropes combined so even if the device would fail and slip, I cannot fall on the ground. I don't use Kong ascenders because the two cam sections are riveted together. The idea of loose rivets makes me feel all warm inside....The device I made myself would still be safe, even if the nuts and bolts would fail with whom they are screwed together...

Therrin

Sounds like a candidate for Dr Storrick's equipment design division.

Eric Frei

Lets see how long it takes Tree Machine to recruit him.

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Tree Machine

I've been awhile getting back to this. I've been searching for Kong dual ascender accidents. I'm sure they exist, but I come at this from a solid 8 years on the duals as my primary ascenders, for both SRT and the doubled line 1:1 ascending method that Quercus is looking to enjoy.

I have other ascenders, though, too. The Petzl ascension, CMI's then other non-handled ones like Pantin, micrograb, and croll.

in '95 or 96 I did exactly what Quercus did to his ascencions, but with CMI's. This involved pulling the cam pin out of BOTH ascenders at the same time, keeping the cams motionless so the springs don't pop and dismount the cams. Then replace those two individual pins with one double-length which jopins the two. Then I drilled 3 small holes, inserted rivets and peened them down. This worked beautifully as the blocky, flat-sided CMI's fit together side-by-side really well. I used these for about a year and then Kong came out with theirs. This was a big improvement as the handle on a single CMI is uncomfortable, and two of them together, doubly poor comfort as far as an ergonomic grip.

To be honest, I don't find the Kong twins to a comfortable grip either. Most of my work of late has been SRT on a blue Petzl Ascension, and the handhold configuration on that is like butta. BUT, except for Quercus' dual ascensions, a dual Petzl simply does not exist, at least that I'm aware of (and having talked personally with the President of Petzl America at a TCIA expo, I have thoughts on why).

Here's a shot of the old, beaten warriors. No loose rivets after all this time, but if the DID loosen, I would either peen the original rivet, or go to the hardware store and get the appropriate size replacement rivet and peen it in.

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Tree Machine

As far as the Kong documentable accidents, I have come up with nothing. My curiosity and pointed question would be this, was it gear failure, or operator error? Was it in normal working conditions, or was it during formal testing.

See, when you test gear, you do all you can do to see at what point or places it can fail. If you are TRYING to make something fail (any product) then you probably will. If you ram the ascenders through branches, or up against a limb just right while pushing up through, then events can happen. I could make Quercus' dual petzls fail if I set my intent to do that, or we could climb safely on them for the next decade without incident.

All ascenders are built pretty much the same, at least from the cam mechanism. Major differences are in the handle design.

We discussed years ago how to back up duals, and how to modify the design of the Kong duals to be more safe.


Basically, this meant shortening the thumb release bars to be shorter, pan-headed, and less like a protruding rod. Place a hole (thru-rivet) in the area where the cam lever seats while disengaged. A keychin biner is inserted through this as a stop, preventing the cam from possibly moving into the disengage position. Add a captive bar (just like Quercus' thru-bolt) to keep the rope from any possibility of escaping the ascender shell and finally, an ATTACHMENT POINT at the top of the ascender for insertion of a locking biner and attachment of your backup.

These first two mods can be done at home, but shouldn't have to be. Kong DID put in the hole for the keychin biner in the last couple years, that helps, but there's still a ways to go, easy, easy to do at the Italy end, and we shouldn't have to mod our gear for enhanced safety. Or reconfigure existing gear into something that's better than current stuff.
Knock, knock..... Kong Bonaiti..... are you home....?

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quercus

guys, I'm gonna take pictures of my device too. I'll post them on this thread ASAP.
I do have something to say that could help you document accidents with cammed ascenders. Not the ones from Kong though, but with the ones from Petzl. Not so long ago, I stumbled upon a failure notice from Petzl itself about the ascension. The reason why seemed very odd to me at first, and it occured to me that this would be operator error, so I tried to let one fail for about a whole day. Petzl claimed that if the ascension with certain lot numers would be tilted far enough in the opposite direction in wich the handle is faced, the teeth of the cam wouldn't grab the rope anymore and the ascender would slip. This in mind and the fact that it is never a good thing to drop load an ascender could result in sheath damage and sheath and rope failure at some point. What was wrong with de device? The bottom teeth of the cam were simply not there and therefore the device became unrelyable.
Because of the fact that I have had an accident once with an ascender because of this problem, and the rope got pretty damaged due to that occurence, I thought that it was worth investigating.
This is what I think of the Kong ascenders:
-The device itself is far to big and bulky
-I feel that Kong made a bad choice between a fool-proof design and a weight problem.Therefore they left essential parts who would make the design tougher out.
-The design from Kong is simply not a unique design, but a modification handle that is riveted onto a small ascender that allready existed. The ones from petzl is not riveted, but a totally new device that is differently forged except from the cam section.
-If it were droploaded pretty good, the rivets could fail, and if that were the case, the device would break apart with one small part going up very very fast and the other bigger part to wich the climber is attached would drop instantly.Far too many rivets who could loosen trough the years and fail at one point in time.
Just my two cents...

Tree Machine

Opinions are good, but I would encourage you to lay your dual Petzls on top of the dual Kongs as a true comaprison. There will be very little size difference.
You might want to weigh your dual set and the Kong dual set and compare the grammage. You state a weight problem.... do you know the weight of the two sets? If you're implying that 10 or 20 grams difference makes a difference, you may be called out on this. What exactly do you consider a weight problem? So, what would be your solution to that? Add more parts? What are your ideas on this? What 'parts' This is really important.
Not unique. Agreed. Rivets are used extensively in industry as a preferred means of permanent connection. I think this last part, Quercus, is pushing the criticism just a bit too far. You're describing a complete, catastrophic failure of the gear. You're also describing climbing above your tie-in point (a no-no) and a fall on ascenders from above the tie-in. Describing an unrecommended action of a climber, a rare fall (we all avoid falling, always) and then speculating on the performance of the gear in this rather unlikely situation, at this point is closer to fiction than reality. I'll take back this last statement if you can provide ONE SINGLE case of a catastrophic failure of a Kong Dual like what you surmised could happen.

I'm not stepping up on Kong's behalf. I just don't want guys thinking rivets are bad because of a one person's hypothetical example of something that could maybe happen. Not sure this Quercus has experience in using the kong dual-handled.

I come from almost a decade of using the Kong Twins day in and day out, single and doubled, wet, dry, snow, 11, 12 and 13 mm lines. I got them the year they came out, and they're the same, original pair, quite possibly the oldest and most highly used pair of Kong Twins on the planet. The rivets are just fine. The ascenders perform identically to the day I bought them, consistently keeping the promise they offer.

There are not a lot of other dual-handled ascenders to choose from. I appreciate Quercus' effort in creating the dual Petzl, but I'm not sure it's a good idea to modify your gear. I do it regularly, but not everyone is mechanically inclined, or confident in doing this. I personally don't recommend altering your gear, but if you do, it's your baby.

So Quercus, now that you can't put a biner through your top holes, how are you keeping the rope from possibly escaping the ascender shell and how are you attaching your backup? Your modification to the Ascensions has erased this ability as we knew it.

Now THIS is a weight problem. Add to it a Silky, a chainsaw and a rack of slings on the other side and that's a rigging kit. The ascenders contribute some to this overall weight, but if a set of ascenders was incorporated, and they are 10 or 20 grams lighter than the previous, the climber will feel no appreciable difference. I just don't get the 'weight problem' comment.

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quercus

You have a few strong points there, but I'll be able to explain better when I have the picture of my device. I don't want to step on any toes here... and I'm seriously against modifying gear. I just combined two proven designs.

George Hayduke

TM,

I sure wish that I could site chapter and verse, but I can't. What I DO know for a fact is that the Kong's have been in more failure accidents than any others. Many of my European friends have shared failure stories. Just because Google, etc. can't find any references doesn't mean that they don't fail. Do what you want.

Here, look at this setup:

Install the Kong's on a pair of ropes.
Look down from the top.
Notice the shells of each ascender wrapping around the ropes?
Pay special attention to how much overlap there is from the shell over the cam.
The shell is shorter and doesn't overlap as far on one side, I think the blue ones.

If a bite of rope gets in the upper part of the access line and the handles are cocked back it is LIKELY to shoehorn the rope over the cam. Next motion=groundfall.

The smaller or larger the rope diameter the more likely this is failure will occur.

For MANY years, currently too, tree climbers use +13mm ropes in too many pieces of climbing gear. That is an accident waiting to happen. Care to defend the use of a too large rope to someone's heirs?

The hitch pin is a clever addition. But why? Go to SRT it's too easy.

There is NO requirement out of ISA TCC to backup ascenders. It is good practice though.

In the mid-80's I got my first pair of Kong ascenders. It was so easy to take off one handle and bolt the two heads together. YEARS before Kong did it themselves. Over the years I evolved into using SRT for access.

Tree Machine

I personally applaud your creating the duals. And really, I'm not trying to be a hard-ass, but a big complaint here, early on, was to sniff out bogus or inaccurate information, be able to verify statements to give them legitimacy, incorporate solid science and stomp out heresay. You make strong statements, just be able to defend them.

Things like saying the Kong ascenders have a "weight problem" yet you don't define what a 'problem' constitutes, as far as weight goes, nor what the ascenders actually weigh. What is up with that? It's called making something up and posting it for the world to see.This is the reason for always having a captive bar (a.k.a. PTO pin).

[QUOTE=George]The hitch pin is a clever addition. But why? I use a captive bar also on SRT, only it is in the form of a caribiner. Keeping the rope from any possibility of escaping the ascender shell is the purpose, doubled rope or single.George, I climb SRT regularly. This evenings climb, just a few hours ago was SRT on the blue petzl ascension single.

Ascending a dual rope, with dual ascenders is easier than SRT for severel reasons, and Quercus gets this. Mainly, I hate rope bounce, and even though I'm on 11 mm KM3 static, there is still bounce on SRT, the longer the distance to the tie-in, the more bounce. Footlocking a twin line is both easier than a single line, and bounce becomes much less pronounced on doubled.

Personally, I like single rope technique the best, but that doesn't mean I use it the most. For fastest, most straight-forward setup and easiest ascent, 1:1 static doubled using dual ascenders. Second easiest SRT, then third the drudgery of 2:1 traditional ascent. Of the first two, I choose which one, depending on the tree at hand, but I'll usually favor 1:1 doubled over 1:1 single. Reason? I'll choose whichever serves the most advantage for that particular climb.

Why just about all arborists still use the 2:1 traditional friction hitch system for ascent is just beyond me. There's just no joy in 2:1 ascent, only painfully slow work. Hayduke gets this.

quercus

Ok so here I am to defend my case... backed-up by some pictures and facts...
Because of the fact that I am certainly not an engineer, I sent an e-mail to an civil engineer from AIB-Vincotte. That agency tests devices and gives them te CE mark that they need in order to be released for the european market. But I'll get back on that later.
At first we look at the facts of both devices. Since I 'don't have a Kong device I'm relying on data from their website.

Weight:
Petzl dual ascencions: 398 grams included the tape and the screw wich holds them together and the rope for security (see picture)

Kong Twin : 490 grams without pto - pin

If Kong had made a device that included full aluminum handles in one piece, wich is way stronger than several parts riveted together, the device would even be heavier.That's what I mean when I say "choose between weight and fool-proof strength". Even though Kong's design is heavier, it's certainly not more durable and strong. Why? The problem is not only the rivets, but the holes in wich the rivets are stamped. If the rivets are aluminum then the rivets will give way first. If they are steel, wich I think they are, the holes will tear apart and therefore the whole design falls apart. The engineer says this problem will occur far before the solid handle material will rip apart. If the Kong device would bend, say when a branch side-impacted the devices fairly hard) the holes could tear apart and get bigger and thereby let go of the rivets. There's also no way to see if the rivets are damaged unless this damage would be catastrophical as you say.
The solid aluminum handles are in fact what I mean by leaving essential parts out.The combination of the two petzl devices here actually doubles the Kn value of the separate sides.That would be 40 Kn breaking strenght. How much is kong's? But that's not really important here...

Thickness:
Petzl : 50 mm maximum
Kong : ?
Widht
Petzl : 91 mm at the widest point
Kong : ?

Weight problem?
When I take a look at your climbing harness, I see a lot of steel for personal protection instead of aluminum. I 'd dare to compare the total weight of your gear and mine and see what's the difference. I made that choice a long time ago. Aluminum for me, steel for rigging. Exept for the steel core of the flipline of course...If you climb better with heavy equipment then that's a good way to exercise some more in the tree. I, on the other hand, have a natural way of leaving excess weight behind when I'm climbing. So in my opinion weight and climbing are opposites.
I also believe that there are no good and bad ways of climbing, only your own way and the way you are most comfortable with.

In the pictures you can also see the screw wich holds the two pieces together and the flat nut wich is used. I did not at all alter anything but chose the components so they wouldn't interfere with the mechanism of the devices. So I didn't drill that hole, that hole was already there. Under the handle material are also holes with screws and spacers. Those holes where originally there to hold the handle in place. The little steel link on the bottom is for attaching a foot loop wherever that may be needed. In order for this device to fail it would have to:
-rip the three screws out of the hole or make them break somehow
-tear the safety prussik and prussik line out of the holes or make them break.
-tear the tape loose (not so difficult)
-make the steel link break (because that actually also holds the two seperate pieces together)
-make the carabiner break or get that hole to tear apart... (not likely)

You see, I'm quite capable to defend my opinion and because I'm climbing for 20 years now (rock, snow, ice, trees, caves, waterfalls, structures, biuldings, whatever) I do have qiute a bit experience on climbing gear. As you can see I can defend my comments on other gear.If I can get my hands on a second hand Kong Twin I'm going to test it destructively to see what fails first, the aluminum handle or the rivets.

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newguy18

Rock Exotica Omni Swivel Pulley Double
is this what your looking for?

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old schooler

quercus

Haha I'm looking for that too, but mainly I'm looking for the dualcender from rock exotica. That's actually a rope clamp.

newguy18

this thing?
Rope Ascenders: Petzl Micrograb, Microcenders, Kong Ascenders, and more

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old schooler

quercus

yeah the dualcender is on that page.

newguy18

So can you order it from them?I know Ekka orders from wesspur so I don't see the issue with out of country orders.

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old schooler

Tree Machine

.

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newguy18

Looks like an accident waiting to happen but then again in this industry so is running a saw recklessly or not double checking your lines.

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old schooler

Tree Machine

Personally, I applaud this;

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Tree Machine

Quercus, you've outdone yourself. As far as the Kong information you offer, destructive testing with objective measurements and observation to see if rivets go, or holes go first. And one or the other will. From my personal years with the Kongs, as eartlier said, are fine. But in 20 years. We just wouldn't know til thin.

As far as the points you put forth about the Petzl duals, there is nothing I can disagree with.

Good Job.

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