|
slacklinejoe
Jun 20, 2006, 9:04 PM
Post #26 of 36
(5516 views)
Shortcut
Registered: Nov 5, 2003
Posts: 1423
|
Dang, that's just sweet. A hybrid between a klehmist & pebernathy (spelling?).
Does it work in those 6 or 8 mm mammut slings? I'd gladly ditch accessory cord that is more single purpose than carrying a few slings.
|
|
|
|
|
moose_droppings
Jun 20, 2006, 10:16 PM
Post #27 of 36
(5516 views)
Shortcut
Registered: Jun 7, 2005
Posts: 3371
|
In reply to: OMFG, people really use the EDK to join their prussik loops? That's retarded.
The only dumb question is the one thats not asked, so......
Would you care to elaborate on this statement?
|
|
|
|
|
slacklinejoe
Jun 20, 2006, 10:48 PM
Post #28 of 36
(5516 views)
Shortcut
Registered: Nov 5, 2003
Posts: 1423
|
In reply to: In reply to: OMFG, people really use the EDK to join their prussik loops? That's retarded. The only dumb question is the one thats not asked, so...... Would you care to elaborate on this statement?
EDK is useful for joining ends of ropes for rappel but even then there are major concerns that must be addressed when using it at all - some of these charcteristics make it less than ideal for prussik use (or at least in my mind it does when comparing the charachteristics of the knot vs it's alternatives such as the double fishermans).
EDK is good for being a non-bulky knot where the tails / knot are less likely to get hung on rock protrusions, it's also easy to undo after being loaded - that's the main selling point of the EDK and neither are are issues when using a prussik.
Safety concerns for EDK
isn't ideal for cyclical loading / unloading
if not dressed extremely vigilantly can be significantly weaker and "roll"
is usually not used anywhere loads beyond what rappeling produces are found - unfortunately I do not have a research study handy that mentions the knots strength - and I've never heard of any research of that knot being used in accessory cord at all.
it's common failure method is rolling (again, may be because of the dressing - can't remember) so you could come completely disconnected long before approaching the breaking strength of the cord.
I've actually never heard of anyone using the EDK in prussik cords until this thread - oddly there were two posters doing so which is very unusual.
|
|
|
|
|
cintune
Jun 21, 2006, 1:13 AM
Post #29 of 36
(5516 views)
Shortcut
Registered: Nov 10, 2004
Posts: 1293
|
In reply to: Does it work in those 6 or 8 mm mammut slings? |
|
|
|
|
moose_droppings
Jun 21, 2006, 1:54 AM
Post #30 of 36
(5516 views)
Shortcut
Registered: Jun 7, 2005
Posts: 3371
|
In reply to: EDK is good for being a non-bulky knot where the tails / knot are less likely to get hung on rock protrusions, it's also somewhat easier to undo after being loaded - that's the main selling point of the EDK and neither are are issues when using a prussik
In reply to: Safety concerns for EDK isn't ideal for cyclical loading / unloading if not dressed extremely vigilantly can be significantly weaker and "roll" is usually not used anywhere loads beyond what rappeling produces are found - unfortunately I do not have a research study handy that mentions the knots strength - and I've never heard of any research of that knot being used in accessory cord at all.
All knots if not properly tied and set are a death knot, and all knots should utilize a backup knot(shouldn't even need to be said). All the data I've read on the EDK suggest the knot is far safer than everyone is concerned about. With body weight alone and a well set knot , rolling isn't problematic, and with a backup overhand, it doesn't even roll. If by knot strength your talking about what the overall strength is left after tying the knot, I would think that a 7mm tied with an EDK has more strength left in it than a 5mm tied with a DF.
|
|
|
|
|
slacklinejoe
Jun 21, 2006, 2:18 AM
Post #31 of 36
(5516 views)
Shortcut
Registered: Nov 5, 2003
Posts: 1423
|
In reply to: All knots if not properly tied and set are a death knot, and all knots should utilize a backup knot(shouldn't even need to be said). All the data I've read on the EDK suggest the knot is far safer than everyone is concerned about.
Backup knots are generally considered unnecessary with the doube/tripple fishermans, proper tails of 2 x the knot length are required though (same across the board). If you are backing up the EDK, it likely is more bulky than the DF knot. The EDK isn't normally backed up when being used in most discussions - so basically you're using a doubled overhand, not the EDK.
All the data you've read on EDK was in climbing rope (unless you've seen something I haven't) - not accessory cord where the margins are much lower and the handling & other characteristics are significantly different.
The whole issue with cyclical loading is still a major concern that isn't going away - people quit using the bowline in it's non-backed up form over those very valid concerns.
Do I trust the EDK for rappels, yes - over the years it has gotten a bad rap. Will I conjecture to promote it over knots which are much less prone to failure for general usage, no.
Regardless, I don't plan on convincing you to change your ways - that's fine as long as I don't have to carry you out., but if you are encouraging a non-standard method over a more standardized method without some major research or major reason you should plan on backing your claims up or get a little flak about it.
|
|
|
|
|
rockguide
Jun 21, 2006, 6:12 PM
Post #32 of 36
(5516 views)
Shortcut
Registered: Nov 8, 2004
Posts: 1359
|
wow - my reference to the EDK on prussiks started some interesting flames.
Classic case of catching glimpses of parts of people's climbing systems and not seeing the whole deal.
For years I tied my prussiks with double fisherman's knots. Measured the lengths exactly, tied the DFK properly (4 parallels on one side, two Xs the other) then bounced the cord a bit to set the knots. It fit with rope ascending patterns I was trained in and was comfortable with. Same era I was bouncing my waterknots for the shoulder and double slings I was using (sewn webbing came later).
For those applications the EDK would be ineffective. Why tie such an unstable knot in a permanent loop?
I use accessory cord (aka prussik cords) for other purposes than rope ascending. Rock rescue, anchor building (rarely) retreat slings, tieing items to the pack, occasionally stringing up a tarp, etc. These purposes are best started with unknotted accessory cord.
When I need to ascend a rope I tie the prussik to the rope at the appropriate landmark, run one strand through my tie in points, and do the overhand on the side below it. Measure distances on the spot, adjust as needed and go. Not the strongest of knots, but loads are low - and if by some odd chance loads increase, the dynamic rope that stretches above absorbs the force.
There is more to the game than that - but it works in my systems.
The people who use the EDK in their accessory cords to prussik probably use similar systems. Those who clip permanent loops, should not use the EDK for their permanent loops.
If I have to use accessory cord for an anchor (less common now - and assumes that I have a cord that can handle anchoring loads) The EDK is inappropriate. The double fisherman's is the knot of choice.
Brian
(ps if you haven't used the rope ascending system I was half describing, get someone who knows it to show you. There are some content gaps).
|
|
|
|
|
lil_monkey
Jun 21, 2006, 6:35 PM
Post #33 of 36
(5516 views)
Shortcut
Registered: Dec 31, 2005
Posts: 57
|
woah, thanx for all your answers. i feel kinda bad stopping this argument because i was kinda enjoying reading it but let me just say i'm making prussiks using 5 or 6 mm accessory cord and i am using a double fisherman's to tie them. im not looking to get into new ways of tying them, at least not online, (i do know about the friction knot already, i just don't trust it as much 'cause im funny like that).
|
|
|
|
|
btym
Oct 1, 2012, 5:27 PM
Post #34 of 36
(3247 views)
Shortcut
Registered: Jun 4, 2010
Posts: 1
|
Here's a helpful table for good recommended lengths for purcell prusiks... lengths would probably be similar is you were using a dub-fish instead of going purcell style.
http://http://swiftwaterrescue.com/technical-rope-rescue/trr-skill-purcell-prussik-building/
|
|
|
|
|
acorneau
Oct 2, 2012, 1:40 AM
Post #35 of 36
(3191 views)
Shortcut
Registered: Feb 6, 2008
Posts: 2889
|
btym wrote: Here's a helpful table for good recommended lengths for purcell prusiks... lengths would probably be similar is you were using a dub-fish instead of going purcell style. http://http://swiftwaterrescue.com/technical-rope-rescue/trr-skill-purcell-prussik-building/
Whoa...
Holy six-year-old thread revival, Batman!
Oh, and made clicky:
http://swiftwaterrescue.com/...ll-prussik-building/
|
|
|
|
|
Marylandclimber
Oct 2, 2012, 8:54 PM
Post #36 of 36
(3123 views)
Shortcut
Registered: Sep 3, 2011
Posts: 224
|
I think in six years he/she found out how to tie and use a prussik... But atleast you didn't make a new thread for this.
|
|
|
|
|
|
