Purcell Prusik Variation

[stickboy42]

Hi All,
sitting here thinking about my purcell prusiks and wondered what you all think about this variation, pros/cons.

I have had a set of purcells tied mostly conventionally for some time now but with a 3 on 2 prussik for the shock absorber. I like that because it grabs similar to a 3 wrap prusik but breaks more like a 2 wrap. Little easier to use. I don't like the figure 8 (F8) follow through component however and tied some using a double fishermans (DF) for joining the 6mm cordage. See the picture below.

Here are my thoughts:
I like the DF better because it is easier for you to vary the wraps of the prusik (sometimes i like to tie a 2 wrap or 3 wrap). It is easier to tie in my opinion and less time consuming. It uses lesses cordage. I'm not sure about the strength difference (i've put this system into my queue to break on the test bed).

Any ideas on this from anyone who uses purcell's regularly or not? Haven't seen them tied this way by many folks and just wanted to investigate if there is a reason or not...

Thanks,
Mike

[stickboy42]

here's something i forgot,

i've been using the purcells in doubled rope technique (DdRT) climbing and find that the 6mm cord does grab the two 1/2" ropes fine but getting anything more than a 2 wrap is impossible with the standard 7" loop since that 7" loop designed for just one 1/2" rope. I know you could add an inch or so and it'd work but then for most applications you'd have too much loop and unessary gain in the system. the DF method would allow for more adjustment in this application....

mike

[servantleader]

The fixed single loop of the Purcell set (at least the set I carry) is tied with a double overhand bend (double fisherman bend), so why not the two adjustable ones also?

And, what you show is way more adjustable than the figure-8 follow through version.

Really nice idea! Solves the problem of having too little loop or too much loop for making wraps around the rope. One can size the loop as you need it.

[MichaelXYZ]

So what ever became of this method, do you still use it? Are there and pro's cons?

[Rescue 2 Training]

If you never intend to clip into the shelf of the 8, then the fisherman's would probably work just fine. You lose a clip in point in favor of a more compact rig.

[servantleader]

If you never intend to clip into the shelf of the 8, then the fisherman's would probably work just fine. You lose a clip in point in favor of a more compact rig.

Have indeed clipped into the shelf of the 8 when ascending past a knot using just the set of 3 purcells. Forgot about that...

[MichaelXYZ]

I was just curious if Mike (Stickboy42) made any conclusions about his version after some trial runs. I just got a spool of 7mm Kernmantle and planned on building a set of my own. I found a website that has instruction for building the Frost 8 type.

http://swiftwaterrescue.com/technica...ssik-building/


P.S. I know how to use the Rescue 8 as a rappel device, but not familiar with the phrase, shelf of the 8.

[Rescue 2 Training]

I was just curious if Mike (Stickboy42) made any conclusions about his version after some trial runs. I just got a spool of 7mm Kernmantle and planned on building a set of my own. I found a website that has instruction for building the Frost 8 type.

http://swiftwaterrescue.com/technica...ssik-building/
Attachment 22245

P.S. I know how to use the Rescue 8 as a rappel device, but not familiar with the phrase, shelf of the 8.

It refers not to a figure 8 descender, but rather the knot itself. When using your Purcell to attach yourself to an anchor or a basket as an attendant, if the Purcell is too long, it is possible to attach the carabiner from your harness over the knot itself. Imagine if your biner were trying to split the knot apart by pulling on it between the legs of the 8.

[stickboy42]

I concur on the shelf clipping. climbers do it all the time at the belay station and it's a very effective with the purcell as well. i hadn't been taught the shelf method when i wrote my original post. -m

[Rescue 2 Training]

Didn't even look to see that the thread was 2 years old. Sorry bro.

[MichaelXYZ]

Sorry for digging up an old thread, I was in the process of making a set of my own so wanted thoughts on his method after having had used them for some time. I went ahead and made the type shown in the link I posted.
BTW, the Purcell also makes a good adjustable dog leash, I made one for my new puppy.