Author Topic: Penberthy knot  (Read 16189 times)

SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1801
Re: Penberthy knot
« Reply #15 on: June 21, 2011, 07:39:31 PM »
On the second attachment it says: "The prusik knot will always hold better if it is right side up as shown below"
That is bullshoot. This is the same as saying: The Prusik with the loop sticking out on the right hand side performs better then the Prusik with the loop on the left hand side. It doesn't. Its the same knot!
> The prusik is symetrical. It works both ways equally well, as there is no difference.



I notice the date of publicly announcing the holding orientation of the prusik in that publication and it reminds me that knot experimentation and use were with laid ropes and cord. So I think the statement is factual and should be considered strongly if you were to use this knot on laid rope.
With modern ropes the prusik works equally well in both orientations, in my experience.

These slip and grip knots are so very dependent on materials used and I strongly advise personal testing before using in life endangering endeavors.

I went climbing last weekend and had a novice climber with me. We "tested/learned" several grip and slide setups. Some with the rope and cord on hand did well for me and the same did Not as well for him. The only difference was about 30 lbs.

I asked the young man to pick his favorite(s) out of the batch and he picked the "standard" 4 coil prusik and the Blake/Prohaska (4 coil as well) Both of those performed easily and he remembered easily. And that is what counts.
These were only used that day for rope ascension, not for autoblock backup.

Get familiar with them all and see what works for you personally for the given circumstances.

SS

P.S. Sorry Dan, my mega-quote was not to satisfy your earlier request. Crazy cyber demons at work is all.
« Last Edit: February 19, 2015, 08:20:46 PM by SS369 »

Bob Thrun

  • Full Member
  • ***
  • Posts: 82
Re: Penberthy knot
« Reply #16 on: June 22, 2011, 04:34:40 AM »
Bill Plummer was the only caver who emphasized tying the Prusik knot right side up.  I have climbed on laid ropes a long time ago.  On some of the climbs I had one knot oriented so I could loosen and move it with my left hand.  I never noticed any difference in holding power because I never encountered a marginal situation.  It would be a very narrow band of conditions where there would be a difference.

Transminator

  • Exp. Member
  • ****
  • Posts: 144
Re: Penberthy knot
« Reply #17 on: June 22, 2011, 08:12:35 AM »
Such language is unwanted here (except by intimation/abbreviation),
and is especially unfortunate when it is so clearly wrong.  You might
take care in faulting something expressly stated (i.e., that suggests
that the particular point was considered, not incidentally involved).

Now, how ... different?!  -- in how the coils are oriented with regard
to the lay of the rope!
 

Point taken and I stand corrected.
I was also hasty in writing it as only later I considered that the author was perhaps referring to the lay
of the rope. I was focused on the knot itself.
I am not editing my post though, otherwise the replies don't make sense anymore.

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Penberthy knot
« Reply #18 on: August 26, 2013, 06:14:04 PM »
  A picture of Penberthy knot, with a short text, in French.
This is not a knot.