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karcand


Jul 15, 2009, 9:20 AM
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Re: [acorneau] Purcell Prusik [In reply to]
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I first saw this on a different forum and thought it was a really good idea. But after trying it out with a 6mm Purcell Prusik, I changed my mind. It worked great the first couple times, but during the third test the prusik slipped. When it slips fully extended, which is not terrible. But when I am in the field, I don't want to use something that only works 90% of the time.

I was thinking though, if I got some 10mm static rope, could I use this method to set up a toprope anchor? This method if it works would be a great easy way to adjust the lengths and equalize the station.


knudenoggin


Jul 15, 2009, 8:30 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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acorneau wrote:
In reply to:
3) Is it a bad idea to use 5.5mm tech cord as a purcell prusik, and why if so? Would it be bad because sliding/slippage could lead to material failure, or because peak forces would be higher because of the material, etc.?

I would not use it for two reasons:
1. You want the semi-dynamic properties of standard nylon cord (reduces peak force).
2. Tech cord has much less friction so it may not hold on itself as well as standard nylon. (Recommended knot for Tech cord is a triple fisherman's.)
I believe that this is mistaken re point #2: the slippage feared from
the ends-joining knot is of the core shedding the sheath--slipping out!
It is not the overall rope quitting the knot.
So, with just that difference, the factor re friction-hitch gripping is not
affected -- it's polyester on polyester (or is it nylon?), not Technora.
BUT, I believe that the Tech Cord is stiffer, and that frustrates gripping
also. In any case, for the first and likely other reasons, Tech Cord is
probably better not used in this application.
(Tom Moyer's site had a miscellaneous-items test report in which a
Technora-cored cord slipped the core from a Grapevine knot.)

In reply to:
5) Are there any hitches one can tie on a single line (instead of a loop of cord) that would be suitable for tying into rap anchors? For example, a tautline hitch (http://en.wikipedia.org/wiki/Taut-line_hitch), tied on two separate cords, each of which is tied off to the harness (***NO*** idea how much force that hitch or the others would hold).
The better friction hitch to use would be Blake's Hitch (which I like to
name "ProhGrip" (or "ProhKlamp" might have a better Austrian flair),
after Prohaska, who described it ages ago, a little prior to Blake.
It is used by arborists to grip rope to itself (equal diameters); it is
somewhat adjustable per cordage by (a) adding an extra turn on its
end-nipping turns for stiff rope, or (b) adding an extra turn at the
away end for slicker but flexible rope. It is more secure against coming
untied than most others. One could use a hitch in each end as a means
to ensure ultimate locking should slippage not abate. (But in some
UK HSE (by Lyon Equip) testing, I think that this hitch exhibited very
little slippage (vs. Prusik, Klemheist, and ... ?) -- 2001? report )

*kN*


trenchdigger


Jul 15, 2009, 8:58 PM
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Re: [knudenoggin] Purcell Prusik [In reply to]
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Here's an example of a potential personal anchor using a Blake's hitch. If the hitch fails, you don't die - always a plus!


This example is tied with a section of old climbing rope. For use as a personal tether, I'd tie the figure-8 into my tie-in points.




(This post was edited by trenchdigger on Jul 15, 2009, 8:59 PM)
Attachments: Blakestether.jpg (126 KB)


knudenoggin


Jul 16, 2009, 12:24 PM
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Re: [trenchdigger] Purcell Prusik [In reply to]
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Not only does Trenchdigger's structure use single rope,
but it is constant in structure (or could be): whereas
the PurcellP can be sometimes loading the hitch in either
direction --with the knot effectively joining ends, or as
forming an eye-knot feeding to the other end--,
this single-rope structure constantly keeps the friction knot
by the Fig.8 eyeknot connection to the harness and feeds
adjustable length out to the Strangle-noose-hitched 'biner
to clip to whatever. One constantly has single line, with
a trio of knots in it under tension (and varying amounts
of slack line in a loose loop, to beware of!).

*kN*
[edit for readability (yes, now I think it's readable :o)]


(This post was edited by knudenoggin on Jul 16, 2009, 7:55 PM)


trenchdigger


Jul 16, 2009, 12:37 PM
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Re: [knudenoggin] Purcell Prusik [In reply to]
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Yup, that about sums it up! The friction hitch staying in the same position, close to the harness is a definite plus, as is the greater adjustment in length than the purcell. It stores nicely when extended to about 1/3 length and clipping the slack loop into the carabiner.


acorneau


Jul 16, 2009, 12:47 PM
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Re: [knudenoggin] Purcell Prusik [In reply to]
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Wow, I just had an idea...

While I use my PP on a regular basis, I know that tying in with the climbing rope is the easiest/simplest/strongest/no-extra-gear-est way to tie in. The problem is you've only got one rope to use to tie in (excepting doubles/twins).

So here's my idea: When tying in to the climbing rope, tie in with a good 4-5 feet of tail after your knot. This way when you get to a 2-bolt anchor you can clove hitch on one bolt as usual and then clove hitch/fig-8 into the other. Simple, no extra gear (save the second biner), elegant!

The only exception I can think of is if you need every last inch of your rope to get to the anchors. While I have heard of this potential problem, I have never personally experienced it.


trenchdigger


Jul 16, 2009, 12:55 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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acorneau wrote:
Wow, I just had an idea...

While I use my PP on a regular basis, I know that tying in with the climbing rope is the easiest/simplest/strongest/no-extra-gear-est way to tie in. The problem is you've only got one rope to use to tie in (excepting doubles/twins).

So here's my idea: When tying in to the climbing rope, tie in with a good 4-5 feet of tail after your knot. This way when you get to a 2-bolt anchor you can clove hitch on one bolt as usual and then clove hitch/fig-8 into the other. Simple, no extra gear (save the second biner), elegant!

The only exception I can think of is if you need every last inch of your rope to get to the anchors. While I have heard of this potential problem, I have never personally experienced it.

Hmm interesting idea. I usually just tie a two-loop 8...

I'm not sure I'd be a fan of that since I can't stand having a big tail in the way when I'm clipping. I almost always tuck the tail back into my figure-8.


tradrenn


Jul 17, 2009, 5:28 PM
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Re: [trenchdigger] Purcell Prusik [In reply to]
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trenchdigger wrote:
acorneau wrote:
Wow, I just had an idea...

While I use my PP on a regular basis, I know that tying in with the climbing rope is the easiest/simplest/strongest/no-extra-gear-est way to tie in. The problem is you've only got one rope to use to tie in (excepting doubles/twins).

So here's my idea: When tying in to the climbing rope, tie in with a good 4-5 feet of tail after your knot. This way when you get to a 2-bolt anchor you can clove hitch on one bolt as usual and then clove hitch/fig-8 into the other. Simple, no extra gear (save the second biner), elegant!

The only exception I can think of is if you need every last inch of your rope to get to the anchors. While I have heard of this potential problem, I have never personally experienced it.

Hmm interesting idea. I usually just tie a two-loop 8...

I'm not sure I'd be a fan of that since I can't stand having a big tail in the way when I'm clipping. I almost always tuck the tail back into my figure-8.

Adam, hopefully you are still in Squamish, I would love to talk to you about this staff some more.

Acorneau`s idea can be improved some more, one could clove hitch a locking biner to the tail and clip it between legs to the chalk bag, that`s what my friend does with his PP, it works well, is out of the way and never bothers him while climbing.

Acorneau thanks for this idea, I will try it this weekend, if I get to go climbing that is.

V.

Edit: This could be something real cool as you can clove hitch yourself to each bolt using just one hand.


(This post was edited by tradrenn on Jul 17, 2009, 5:44 PM)


bill413


Jul 17, 2009, 6:43 PM
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Re: [tradrenn] Purcell Prusik [In reply to]
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I'm just having a hard time envisioning this vs. clove hitching the loop of rope between me & my belayer/last piece into the anchor.


acorneau


Jul 18, 2009, 7:09 AM
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Re: [bill413] Purcell Prusik [In reply to]
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bill413 wrote:
I'm just having a hard time envisioning this vs. clove hitching the loop of rope between me & my belayer/last piece into the anchor.

I'll try again:

Tie in to the rope (i.e. fig-8) as usual except tie in so you have a 5 foot tail after your knot.

When you arrive at a 2 bolt anchor, take that 5' tail and clove hitch that to the first bolt. Then pull up some slack from your lead line and clove hitch that to the second bolt.

Ta da!


bill413


Jul 18, 2009, 6:38 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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acorneau wrote:
bill413 wrote:
I'm just having a hard time envisioning this vs. clove hitching the loop of rope between me & my belayer/last piece into the anchor.

I'll try again:

Tie in to the rope (i.e. fig-8) as usual except tie in so you have a 5 foot tail after your knot.

When you arrive at a 2 bolt anchor, take that 5' tail and clove hitch that to the first bolt. Then pull up some slack from your lead line and clove hitch that to the second bolt.

Ta da!

Ah - much clearer to me now. Thanks.

So the advantage is "equalizing" the load on the two pieces.


shu2kill


Jul 18, 2009, 8:18 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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so now you are tied in to two points, without the need of extra gear.

however, i have another question. you climb to the top of a multipitch route, and now you have to rappel down. how do you tie in to the anchors to pull the rope to set it at the rap station for the next pitch down??

or does this clove hitching thing only works in single pitch routes??


acorneau


Jul 19, 2009, 6:03 AM
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Re: [shu2kill] Purcell Prusik [In reply to]
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shu2kill wrote:
so now you are tied in to two points, without the need of extra gear.

however, i have another question. you climb to the top of a multipitch route, and now you have to rappel down. how do you tie in to the anchors to pull the rope to set it at the rap station for the next pitch down??

or does this clove hitching thing only works in single pitch routes??

Well, I only came up with this idea just yesterday so I hadn't thought through all scenarios. For raps I would use a separate system (Purcell, slings, etc).


bill413


Jul 19, 2009, 8:00 AM
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Re: [acorneau] Purcell Prusik [In reply to]
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acorneau wrote:
shu2kill wrote:
so now you are tied in to two points, without the need of extra gear.

however, i have another question. you climb to the top of a multipitch route, and now you have to rappel down. how do you tie in to the anchors to pull the rope to set it at the rap station for the next pitch down??

or does this clove hitching thing only works in single pitch routes??

Well, I only came up with this idea just yesterday so I hadn't thought through all scenarios. For raps I would use a separate system (Purcell, slings, etc).

Let's see - I'm a bit foggy on the previous discussion on this thread, so I don't remember the constraints on our situation, but...
With minimal extra gear, bolted anchor:

Tie into system as acorneau has suggested. Pull up rope so you now have both ends. end of rope through chains. Pull both ends of rope through your hands so that you wind up with the middle point of the rope hanging through the chains. Rig your rappel device. Double check the rigging of your rappel device. Untie one the clove hitches from the chains. Check your rappel device. Untie the 5 foot tail. Rap down (you can keep the end of the rope still tied to you while doing this). Tie into next anchor. Repeat.

Sigh - I'll try to bring up some extra gear with me next time...It'll make it easier.


(This post was edited by bill413 on Jul 19, 2009, 11:11 AM)


shu2kill


Jul 19, 2009, 8:35 AM
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what i usually do, and i think many people do as well, is use a PAS and a clove hitch on the rope to tie myself to the chains when going up. but i also bring my purcell prussik, so when im going to rap, i use the prussik and the PAS.

i found the purcell prussik is very helpful for rappeling, because you can rig the rappel device, release the PAS from the chains, and then you just need to adjust the lenght of the purcell prussik until the decive loads, unloading the prussik...


tradrenn


Jul 19, 2009, 10:41 AM
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Re: [shu2kill] Purcell Prusik [In reply to]
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shu2kill wrote:
does this clove hitching thing only works in single pitch routes??

Best situation for this idea to work would be leading multipitch route were you are leading every second pitch.


alexoverhere


Jul 23, 2009, 3:34 PM
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Re: [trenchdigger] Purcell Prusik [In reply to]
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thanks acorneau, trenchdigger, and everyone else for your comments.

i like girth hitching the PP to the harness because it allows you to easily remove it, flip it around, tie a prussik on the rope, and then either 1) clip the other end into your belay loop (just like majid's pictures show) for a waist prussik or 2) use it as a foot loop for ascending. come to think of it, perhaps the potential to ascend with the purcell prusik is reason enough to not use tech cord (which doesn't work well as a friction hitch on rope) or a single-cord adjustable tether...


alexoverhere


Jul 23, 2009, 3:53 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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the extra figure-8 tail tether idea for 2 bolts is interesting, but is this for belaying or setting up to rapel? in either case, if i understand you correctly, your primary goal is to save gear. if so, why not do one of the following?

1) clove hitch to Bolt A. clove hitch to Bolt B. (obviously this unequalized).

2) clip a draw to each bolt. assume they're both in reach. clove hitch to Draw A and run the rope back down to you. clove to an HMS locker on your belay loop. run the rope back up to the Draw B and clove. now you have redundancy and pre-equalization. (if Draw A but not Draw B is out of reach from your stance, clip the rope to it but don't clove off in the first step. if both draws are out of reach, clip into Draw A, the HMS, and Draw B, and then once at your stance, clove hitch twice at your HMS.)

Personally, for belay anchors, i almost always equalize the pieces with a sling (sliding X / figure-8 / equallette power point) or draws and clove hitch to a locker on the power point. I suppose 2) would be useful if there was a large tree or horn that a sling wouldn't fit around.

For rappeling, i use my purcell prusik at a power point, unless it's awkward/too long, in which case i'll directly clip into one anchor point with my purcell prusik and to another with a sling or draws or whatever i have sitting around. i'd always want to have my prusik as an extra cordelette / for ascending anyway, so i don't consider it extra gear.


acorneau


Jul 23, 2009, 5:22 PM
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Re: [alexoverhere] Purcell Prusik [In reply to]
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alexoverhere wrote:
the extra figure-8 tail tether idea for 2 bolts is interesting, but is this for belaying or setting up to rapel?

The thought came to me thinking about climbing. It wouldn't be so convenient while rapping.

You bring up a few other possibilities which I'm sure are viable, and quite possibly preferable, in some circumstances. My belief is to know as many techniques as possible so you can choose the most appropriate for the circumstances.


ml_nelson


Nov 18, 2013, 4:26 PM
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Re: [acorneau] Purcell Prusik [In reply to]
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I have my own variation on the Prucell. My desire was to incorporate a loop to rappel from.

The top left loop is to clip into an anchor. The small cord, a klemheist (but Prusik works too), is to adjust the length of the lanyard.

The loop with the black plastic protector is where I clip to my harness.

Note that the small Klemheist cord is wrapped around the orange cord a few times under the black plastic. This guarantees that when clipping to this loop, you have clipped both the orange cord and the small Klemheist cord. (the black plastic also makes it easy to identify what loop goes onto the harness)

Lastly, there is a short loop for rappelling off of. I sized it to my preference for a short, extended-rappel.

The big knot is a figure-8 with 3 passes of cord in it. (Note that the bottom end of the figure-8 has only 2 cords used for the loop, so the third cord is tied in a small stopper knot)



Thoughts?
Attachments: Prucell-2.jpg (108 KB)


majid_sabet


Nov 18, 2013, 8:02 PM
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Re: [ml_nelson] Purcell Prusik [In reply to]
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ml_nelson wrote:
I have my own variation on the Prucell. My desire was to incorporate a loop to rappel from.

The top left loop is to clip into an anchor. The small cord, a klemheist (but Prusik works too), is to adjust the length of the lanyard.

The loop with the black plastic protector is where I clip to my harness.

Note that the small Klemheist cord is wrapped around the orange cord a few times under the black plastic. This guarantees that when clipping to this loop, you have clipped both the orange cord and the small Klemheist cord. (the black plastic also makes it easy to identify what loop goes onto the harness)

Lastly, there is a short loop for rappelling off of. I sized it to my preference for a short, extended-rappel.

The big knot is a figure-8 with 3 passes of cord in it. (Note that the bottom end of the figure-8 has only 2 cords used for the loop, so the third cord is tied in a small stopper knot)



Thoughts?


what size cord is used on your prusik?


ml_nelson


Nov 18, 2013, 8:20 PM
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The small cord is about 6mm, the large orange is about 9mm.

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