Another descender for your contemplation

[Burnham]

Over in Hobby Climber's thread about the RQ3 Q8 descender we got to talking about some other descent devices, etc. Here's one that won't twist your rope, isn't too heavy or bulky, and offers a smooth ride with adjustable friction w/o re-rigging and an easy, solid lock/unlock.

It's a CMI mini rack, and while it certainly isn't for everyone, maybe some of you big tree climbers who have to handle long rappels would like to see it. It happily runs single or double rope in 11mm. It's a little snug but still works well enough running 1/2 inch rope doubled...single 1/2 inch is no problem at all.

Pics now.

 

[MasterBlaster]

It looks like a cool gizmo!

 

[SkwerI]

It looks like it does not put any twist in the rope at all, so that is a major plus.

 

[Burnham]

Racks are great for giving a high class ride, smooth as silk and no twisting...but most are just too bulky for use in trees...this one isn't too bad. You can get it with hyper bars, too!

 

[Bounce]

Hyper bars?

 

[NickfromWI]

Hyper bars?

 

[Burnham]

Hyper bars?

Hyper bars are extra long bars for the rack. They often have a peg mounted on one or both ends. They allow easier lock off...or the application of extreme friction.

I guess rappel racks are not well known in the tree climbing world, eh? Funny, the FS climbing program has been using them for a couple of decades at least.

Check this link, click to enlarge the hyper bar equipped racks.

http://www.cmi-gear.com/catalog/descenders/MRACK.asp

Ahhh, Nick beat me to it.

 

[NickfromWI]

I guess rappel racks are not well known in the tree climbing world, eh?

From what I've seen, arborists and tree workers haven't really "discovered" the rack yet. Recreational climbers, on the other hand, are quite away of what it has to offer.

I've yet to buy one.

love
nick

 

[Burnham]

Maybe I should post some pictures of my 6 bar rack too, then .

 

[NickfromWI]

Are additional bars just to accomodate heavier loads?

love
nick

 

[Hobby Climber]

Are additional bars just to accomodate heavier loads?

love
nick

-----------------------


...like fat climbers?

 

[No_Bivy]

racks = no twist..........but are bulky

 

[Wagnaw]

How do you lock it off?

 

[wiley_p]

Years ago I used to do high rise window washing. Kind of fun, got to do some of the tallest buildings in Seattle. My normal descender was a 'fitch' which was just a small four bar rack with the hyper bars. Worked great for up to 600' descents.

 

[sotc]

kool tool

 

[Frans]

Burnham and Nick, why on earth are you discussing racks with no mention of the extreme hazard associated with using them?

Their is a reason why the Petzl stop, and other descending products are more widely sold by tree equipment companies.
The Petzl Stop, the Anthron, Gri-gri etc have built in safety features. The rack is wide open unless a completely separate locking method is installed into the system.

On further thought, I understand why Nick does not mention it, as his experience with tree work is not as in depth as yours Burnham. But really, their is a very good reason why the rack is not widely used in tree work.


The rack REQUIRES a completely separate back up.

Closest tool to a rack that tree workers use is the figure eight. And that really should be used with a separate back up. Figure eights however can employ a 'built in' locking feature, by using the rope. This can be used even if that figure eight has no 'ears'.

 

[NickfromWI]

Frans, I would regard the rack and the 8 to be very similar. Both can be locked off with just the rope, both are more safely used if you put a prusik above or below it as a separate safety.

love
nick

 

[Burnham]

I am in agreement with Nick.

Frans, I could not disagree more with your absurd statement that the use of a rappel rack is attended by "extreme hazard".

Sorry to use such blunt language, but you're off the res on this one, imo.

If we wish to make a rule that any discussion of any device, tool, technique, or piece of equipment can only be undertaken if it includes full coursework on all potential risks associated and all mitigation methods that should be employed with said device, tool, technique, or piece of equipment....um, ok, but that isn't the rule yet .

 

[Frans]

If we wish to make a rule that any discussion of any device, tool, technique, or piece of equipment can only be undertaken if it includes full coursework on all potential risks associated and all mitigation methods that should be employed with said device, tool, technique, or piece of equipment....um, ok, but that isn't the rule yet .

That is a great thought. You all should remember that the tools, techniques, etc. discussed on these forums are usually way in advance of what the typical tree guy in the field has ever even dreamed of, much less used. Thats a fact. We who teach climbing skills, go to trade shows, are cert. arborists, represent an incredibly small majority of the tree worker population.
The figure 8, the rack, can both be locked off, however they DO NOT incorporate an auto locking system to them. Let go, fall.

Here is the sentence which I made that is not exactly correct:

"The rack is wide open unless a completely separate locking method is installed into the system".
What I SHOULD have said, and did not, is that the climber MUST tie off this device in order to lock it".

What I feel you both should have noted is that the figure 8 & the rack, both allow free fall if not locked off. Kind of an important point, don't you think?

IMO, this is one of the reasons why tree equipment companies do not normally sell the rack as a normal tool for descent. NOT, as Nick suggested, because they have not 'picked up' on this tool.

My reason for bringing this up, is a youtube video I watched once, of a climber spelunking into an open pit cave. This climber descended a bit on the rack, then let go of the rope. You can see him attempt to grab the rope as his speed increased, but the friction was too much. He plummeted to his death.

I attempted to find this video, but could not. I may have been using the wrong search words, or something... Horrible video to watch.

See my post on the Buzz, if you care to. I would welcome your input.

 

[NickfromWI]

this is one of the reasons why tree equipment companies do not normally sell the rack as a normal tool for descent. NOT, as Nick suggested, because they have not 'picked up' on this tool.

Frans, I'm not quite sure I'm following you there. The same reason applies to the 8, but if you do a cross country poll and gather up all the 8's in tree trucks, and gather up all the racks, you will have many, many 8's and only a few racks.

It's not the lack of lock-off feature that is holding the rack back in the arb world. It's something else.

love
nick

 

[Frans]

You could be right, Nick. The reason may be because the rack is more suitable for longer descents. While the 8 is more compact. The rack takes some fiddling to set up on the line. NOt alot, but more than the 8.

All the more reason to qualify the pros AND cons of each device before presenting them as being ideal for tree work.

 

[NickfromWI]

All the more reason to qualify the pros AND cons of each device before presenting them as being ideal for tree work.

I disagree. I don't think we here bear the responsibility to looking out for the other guy. We present information as we see fit or desire, but in the end, it's caveat emptor.

I don't think forum visitors really look at a thread like this and go, "well Burnham seems to like this thing, and Nick admits rarely ever using one, but he seems to be fond of it, too...I think I'll get one and start using it right away."

A person can quickly ask, if they are interested, "Hey- I'm thinking about getting this, but no one has mentioned the cons. What are they?"

We here, in my opinion, should be free to just chat.

love
nick

 

[Burnham]

Frans, please...I'll be greatly surprised if you can come up with a quote from either Nick or me where we said anything like "presenting them as being ideal for tree work". In fact, my opening post noted that the rack would not be for everyone, just a limited application for tree climbing.

Be that as it may, other questions regarding the use of the rack have been asked, so I took a few more pics to share.

First, the six bar rack does allow for handling greater loads under complete control, with a wide range of friction adjustable on the fly. It also sinks heat generated by long drops with greater efficiency over smaller devices.

My six bar is an eyed SS frame, with one titanium hyper bar. The other 5 bars are aluminum...one straight slot and 4 hooked slot. The straight slot keeps the user from mounting the rope backwards. I usually run it on 4 bars on doubled rope, 5 or 6 on single. You can engage/disengage bars on the fly, too.

Here's some pics of it mounted and locked off both soft and hard.

 

[Burnham]

Here's pictures of how you lock off the mini rack. Since it's a U frame, with no hyperbar, it goes a little different, but not much.

The U frame does not drop or add bars easily like the open legged type (see my six bar), but more or less friction is till available by spreading the bars apart or pushing them closer together. That same deal goes for the 6 bar, too.

The first 2 pics show the bars spread and then pushed up close.

Then pics of locking off.

 

[Bounce]

I like to use a Klemheist knot to back up my fig 8. It turns my 8 into a self-braking descender so that I stop if I let go. I learned it from the Tree Climber's Companion, by Jepson.

Disclaimer: the above statement is not intended to take the place of formal instruction by a certified expert. Neither myself nor my lawyer are certified experts in anything except Donkey Kong. Anybody reading the above statement is responsible for their own safety and may not blame me for an accident even if I cut the tree down while you were in it.