Why are mobile fall arresters uncommon for top rope solo?

Every time the Camp Goblin or Petzl ASAP get brought up for top rope solo, it seems like the MP masses dismiss them. On the surface, they seem like the perfect devices. I remember some MPers who used such devices at work saying they were not good for TRS. What are the downfalls of these devices, and why aren't they more common?

My guess is that it is primarily due to the price of them vs other devices, followed closely by rope size compatibility. Perhaps weight too.

If you are using one of these, do you use any type of backup device or knots? It sounds like it wouldn't be necessary, based on how the device is meant to be used.

Would like to get some input from anyone who has used this type of device, either in professional use or for TRS. What would you change to make it better for recreational climbing?

J C wrote:

My guess is that it is primarily due to the price of them vs other devices, followed closely by rope size compatibility. Perhaps weight too.

Yep.  Nailed it.

It isn't much more exciting than "they're somewhat adequate on paper, but they're outperformed by a variety of other devices in practice."

In the case of the Goblin, people certainly TRS with it. It doesn't have the following of many other devices because it just doesn't really make a lot of people's socks go up and down. Also a tiny bit harder to find at many retail haunts than other solutions.

The ASAP is considerably more of a mismatch for the job of TRS. It's supposed to be used with an energy absorber, it's only recommended for low-stretch ropes, if you're using it properly there's a pretty high clearance (distance from the ground before you're pretty sure you won't hit the ground), it's expensive, it's heavy, it's bulky, and then the technical copy advises against having it lock repeatedly plus there's something about the standard it's built to (I think, but don't quote me) that requires that you retire it after a fall. If I only had an ASAP and I needed to TRS away from a bear, I'd slap it on there and send the rig without blinking, but when I'm looking at the price tags and tech specs and tech notices and deciding what I want to hike to the crag and take a bunch of little falls on over and over, it doesn't make the cut.

I can't tell you anything about its use in TRS, but I work with the Petzl ASAP as a routesetter. It's my backup device, I have to install a backup line to use it, it protects me against failure of the main system (rope and/or positioning device). I'm pretty sure it doesn't give a soft catch, and you have to replace the absorber once the device has engaged.

There are no knots underneath, but you have to make sure the backup line is heavy enough so the ASAP runs smoothly, i.e. doesn't just pull up a section of the rope. Also, yes, it follows you up, but for it to work properly and catch you as early as possible you have to push it ahead of you. I don't think it's convenient for recreational climbing.

Is there anything specific you would like to know? 

Camp Goblin is my TRS device. It works great, runs smooth, and doesn't need a chest harness. A++.

Because they're completely unnecessary

I used a Goblin on about 5 outings then sold it. I found the attachment point always crossloaded and the device always caught in everything. After every outing, I was always messing around with a different carabiner, maillons, rubbers bands, Petzl Tangas etc. If I had to TRS using it, I would use backup knots.
It doesn't work well with ropes of thickness <10mm either.
Nice build quality though, just not for TRS.

My setup is a DMM Ceros, and one fat rubber band, and I've never had any issues. The Ceros has a keeper piece so it can't move on your belay loop, and it has a nose feature that won't let the Goblin cross load. Also, I've used a 9.8 Eternity dynamic rope from Mammut and it works perfect. Weird to hear complaints in areas I've never had trouble with. I do use the device in its "Up Only" mode though, so maybe he had trouble with the Up/Down mode.

I used a camp lift for about 2 years, then got a camp goblin used on here for pretty cheap and started using that. Both work well and the up/down mode on the goblin can work for down climbing or rappelling without removing it as long as you are careful and move smoothly. That said, it's a lot heavier than the lift and 2 to 3 times as expensive if you buy it new. Given all that, I would recommend the lift before the goblin for someone looking to by a device solely for tr solo

Thanks for the replies everyone, very helpful. I am a grad student in product design, and will be designing a TRS device for a class. I have been curious about mobile fall arresters for a while, and this project has prompted me to learn more about them. Whether or not that is the direction I go, there is probably something to learn from them.

It looks like the Goblin and ASAP use very different mechanisms. Are there any other mobile fall arresters out there? Can anyone point me to companies or product names to check out?

Any arborist ascenders that have applicability to TRS? 

Matthew Jaggers wrote:

My setup is a DMM Ceros, and one fat rubber band, and I've never had any issues. The Ceros has a keeper piece so it can't move on your belay loop, and it has a nose feature that won't let the Goblin cross load. Also, I've used a 9.8 Eternity dynamic rope from Mammut and it works perfect. Weird to hear complaints in areas I've never had trouble with. I do use the device in its "Up Only" mode though, so maybe he had trouble with the Up/Down mode.

Do you use a second device and/or backup knots, or are you 100% on the Goblin?

The main mechanisms are:

Teeth on a cam

• Microtraxion
• Spoc
• Croll
• Handled ascenders, etc...

Bend in the rope + pinch

• Camp Lift and other Ushba knockoffs
• Goblin, Kong Backup, (same category as above, but more features, heavier)
• Taz Lov2/3 (same category as above, but controlled lowering under load)
• Shunt
• GriGri, Cinch, etc... (GriGri does not tend itself, Cinch can, but it is not used often for reasons which are I'm sure are good, but I can't remember. Failure modes and such.)

Friction / Constriction / Bends (not common to use for TRS)

• Friction hitches pushed up using something, even as simple as a quicklink or pulley

Other weirdness (common for LRS not TRS)

• Silent Partner
• Revo
• Clove

J C wrote:

Do you use a second device and/or backup knots, or are you 100% on the Goblin?

I use an Edelrid Spoc on a 60cm sling to keep it well below the Goblin. Never had the Goblin slip far enough to have the Spoc catch me. Not sure if it would ever actually catch me, as opposed to just being a jammer that would stop the Goblin.

Not sure if you've come across this yet, but I uploaded a video of the Goblin's inner workings a while back.

https://youtu.be/HPJKgTCWd2g

Because you shouldn’t be taking repeated falls on an ASAP/ Absorbica combo, the absorbica is designed as a one time use shock absorber and is supposed to be retired when you blow the stitching out. That would get expensive real quick

Sherpthederp wrote:

Because you shouldn’t be taking repeated falls on an ASAP/ Absorbica combo, the absorbica is designed as a one time use shock absorber and is supposed to be retired when you blow the stitching out. That would get expensive real quick

Well, the critical thinker might reason that the screamer is there because the device is commonly used untended on a 3' long tether in combination with a static rope. Some of us rule breaking top rope soloists might get the idea that you could clip the ASAP to your belay loop, keep slack out of the system, and be perfectly safe on a static or dynamic rope without using a screamer.