Petzl Basic Modification

[Scott McCrea]

In this thread, the topic of Petzl Basics with the plastic thumb lever coming off the rope while climbing. I figured this is worthy of it's own thread...

Back in 2000, I sewed a new foot harness for my Rope Walker system. I used a new style Petzl Basic with the plastic thumb lever. On the next four trips, while climbing tandem, the Basic came completely off the rope 7 times. This was most certainly due to the extra forces and different angles associated with tandem climbing and the design of my foot harness. Because my other foot was catching on the lever and opening the cam.

So, I modified the plastic thumb lever with a Dremel tool so that it doesn't stick out and is less likely to be opened by accident. This mod has prevented it from happening again.

Here's a couple pics of what I did. The first pic show that I left a little bit of the lip sticking up. It's just enough to operate the lever somewhat normally. The second pic compares an unmodified lever on a Left Ascension to my Basic.

[NZcaver]

Nice idea!

Another alternative - you could try finding some old-style Basics/Crolls. I don't imagine they would open quite as easily.

I might even still have a couple of those laying around somewhere...

[Scott McCrea]

Yep, the old style doesn't have this problem. But, the shape of the shell changed a little and the new version shape is a little better for foot ascender use.

[Ralph E. Powers]

I've climbed tandem out of deep pits before using a Petzl basic for my foot and a Croll for the knee. Been the top climber and the bottom climber on either occasions. Never had a problem or had anyone else for that matter complain of the ascender coming off the rope (repeatedly... or even once) so never gave it too much thought. It worked and worked fine.
When training people I tell them to take short smooth steps to conserve energy and movement, that there is no rush, there's no need for it.

I'm going to be dropping a 220 foot mineshaft this weekend with my ropewalker for the ascent back up. I'll take notes and even try to knock my basic off the rope to see what might also be a contributing factor.
I'll let ya'll know what I find.

[bonniecrystal]

http://www.expeditioncave.com/srt/petzl/failure/

[Ralph E. Powers]

Well the basic that I used last Sunday worked just fine. It was the older style basic with the metal protruding thumb catch and the double holes near the top. It was the foot ascender for a double bungee rig that I was using for a 95' ascent out of a free-hanging drop. For the knee I was using a newer model Croll (plastic thumb cam release)... both worked just wunderfully.

[Mark620]

could someone post a picture of the older Petzl ascender?

[Scott McCrea]

could someone post a picture of the older Petzl ascender?

Here's some shots of the old style Petzl Basic and one of the old style Croll. BTW, I found these by Google-ing for 'Petzl Basic' and clicking the 'Images' option. Enjoy!

[caverd]

http://www.expeditioncave.com/srt/petzl/failure/

Bonnie,

I read the formal response from Petzl America dated May 2, 2004. It doesn't appear as though there is any relevant information in the response. It talks of Redundancy (use multiple ascenders), Interference (keep the ascenders from touching anything), Ease of Use (designed to be operated easily), and Perspective (seems to not say much beyond what was coverd in other sections of letter).

This issue is a real concern. If anyone has experience with the older versions of these ascenders coming off rope as easily as the newer ones, I would like to hear about it. Watching my friends son have two of his Petzl ascenders fail three times each while climbing out of a pit was enough to scare me. Has Petzl done any formal evaluations of the failures to determine possible design improvements? As an ISO 9001 registered organization, Petzl has an obligation to formally review something like this. Has anyone asked for the results?

[Mark620]

Good Point Caverd,

Someone should talk to ISO about this...

[fuzzy-hair-man]

Some more photos of Petzl ascenders from Gary Storrick's webpage which has HEAPS of vertical gadgets (Good for window shopping)

Ascension: (Versions A, B1&B2, C1, C2, D) left to right top to bottom:


Croll (Versions A,B,C,D) left to right top to bottom:


Basic (Versions A,B,C,D,E,F) left to right top to bottom:


Check out his website at:
http://storrick.cnchost.com/VerticalDevicesPage/VerticalHome.shtml

[hunter]

Hey Scott,
Could you post another picture of the modified/unmodified ascendors from a different angle? I'm having trouble seeing exactly what you did.

Thanks,
James Hunter

[Scott McCrea]

Hey Scott,
Could you post another picture of the modified/unmodified ascendors from a different angle? I'm having trouble seeing exactly what you did.

I'll do it. It may be next week before I get a chance tho. I'm busy getting ready for VAR now. Don't hesitate to remind me if you don't see anything in a week.

[Mark620]

It looks like the croll will not do what the others will(open when slid by a rock just right) it has a different type of plastic lock.

[hunter]