toothed cams in MA system

[Leroy]

L

 

[Treetopflyer]

If it wasn't his rope then unfortunately for whom ever bought it will likely not get the longevity out of it if that's a practice he uses often , however minute the degradation due to toothed ascender abuse that is definitely rougher on rope than a prussic, especially in a m.a. system.
Not to mention strength. Therefore a bit more security. My 2¢

 

[Treetopflyer]

I'll add for a quick n dirty setup on light pulls probably no big deal. 5/8 bull rope required heavy pulls I wouldn't dare.

 

[Tom Dunlap]

I'm with you.

There aren't many places in a rigging MA system where I would use cams of any kind. The loads can easily exceed their SWL which can lead to accidents.

My preference is to use cordage and friction hitches with progress capturing pulleys. If something goes pear-shaped hitches will slip/grab rather than go into failure mode.

As far as I know there are only a couple of camming devices made for 5/8" rope. Macrocender and large Gibbs come to mind.

 

[KevinS]

I use the smoother bump style ascenders in mild hand pull systems that are fairly straight forward. However I never use the toothed ones any more, on heavy pulls or a chance of something being not textbook I use an eye to eye but preferably a butterfly.

I used to think if they're for ropes they must be ok but pulling over a pinky based 90' sugar one day with a heavy lean we had a 3:1 on to the tree with a 5:1 on that. When the tree began to stand up the stump crumbled on the one side and the tree went side ways. Which was ok because the only targets were behind us (a golf hole green). The rope held but where it was attached with a cam it did break at the last second.

It was in a bit of a bush lot and we had everyone well clear of the area etc so it finished ok, but never again do I trust an ascender on a heavy crucial load. Butterfly is my go to or a double bowline if it's a separate line( easier to untie, I find)

 

[BEH2202]

I recently went to a training seminar where Jared Abrojena was speaking and the topic of toothed cam devices was brought up. Apparently he in conjunction with Petzl did some tests and found that even at relatively low loads the devices that they tested had the potential to damage the rope. This discussion was a segue into techniques for backing up a hand ascender, but the information is also relevant here. I would be hesitant to set up anything more than a 3:1 tensioned by a single individual with any cam style hardware at all including progress capture pulleys, especially on double braid rope. I think software is the way to go for that application. I would make an exception for a RIG, ID, or similar device being used as a progress capture/brake in a MA system.

 

[colemanjessenz]

I regularly use a pro traxion for a progress capture device in a three to one setup and I'm pretty happy with it as long as its being tensioned by hand .
camming devices are efficient and have there place and imo its with small loads as you guys have discussed.

As for damaging ropes , the ropes i use for the m.a are work ropes and are used accordingly ,this means light rigging ,speed lining etc etc .
i wouldn't be to worried about the wear from the ascender.

 

[RajElectric]

I usually don't have any sort of skilled or reliable ground help, so I stick with a maasdam rope puller.

 

[wyoclimber]

Yeah, small loads, I've got no problem with camming devices in MA. Something where you'd need to be running a 5/8 bull rope, no way.

 

[kstreehuggerco]

Im all about simplicity. There are a gazillion ways to set up a Z rig but I prefer keeping it simple with just prussics, pulleys and a good knot that is easy to untie after you put a load on it. A butterfly or bowline on a bight tend to be hard to work out so I use a knot that was taught to me when I first started climbing. I dont know the official name of it but I just call it the Alabama Booger Knot. Quick and easy to untie its one of the first knots I teach a new groundie. I may have to post a pic of it and see if anyone knows the real name of it.

As far using an ascender or rope grab on heavy loads, use your own judgement as the situation dictates. I have been guilty of it in the past but was well aware of the limitations of my gear. Both knots and mechanical harware can cause a rope to fail because it causes stress on a pin point area on the rope.

 

[RescueMan]

A toothed camming device is designed ONLY for one-person ascending or for light equipment hauling. The rounded-tooth closed-shell cams (such as Gibbs #2, Petzl Rescucender/Microcender, CMI Ropewalker, PMI Progressor) are intended for rescue loads (up to 600 lbs), but nothing is easier on ropes or safer than a prussik rope grab or progress capture. Any knot in the loaded rope, of course , weakens it - while a prussik does not and becomes the sacrificial element.

Here is what can happen with a brand new 1/2" static kernmantle rescue rope and an open-shelled toothed ascender. It strips the sheath off the rope and bends open the shell.