Opposed prusiks

[obsydian]

Seems that many folks are taught that their prusiks need to be placed on the rope in reversed position (for glacier travel). If you have been taught this practice, or do it from habit, what is the reason? Trying to settle a heated discussion.

[jja]

huh !?

[obsydian]

When tying into a rope for glacier travel, you put your Texas prusiks on the rope, the foot prusik and chest prusik. Do those have be tied in opposite directions?

[obsydian]

I'd put a picture in but can't figure out how to get it to display, only tag along as an attachment.

[salbrecher]

Would it even make a differance what direction they're tied in. If i'm picturing what your trying to describe I can't see how it would?

[iain]

I know what you are talking about. Prusiks grip by bending the line. Doesn't make a scrap of difference in the real world, in my opinion. There's too much "lore" going around w/o enough testing to back it up.

[Terminal_Gravity]

There's too much "lore" going around w/o enough testing to back it up.

 

Werd up ... Or... I hear you ,man ...Or... Yes, I believe I agree with your response, Iain.

[obsydian]

I've been told two reasons:

1) If not opposed, you will 'spin' around ascending the rope

2) Makes it easier to climb with two hands on the knots as your thumbs can work each knot loose easier if opposed

 

Trying to figure out if this is folklore

[iain]

Set up a rope and climb up it and see if you find this to be true. My guess is you won't tell the difference, but I could be wrong. I'm not losing sleep over it.

[Skisports]

From Pratical experance I have found that it dose twist the rope not enough to notice but the main reason is so the bar tack on the prussic is facing towards you so you can realease the knot faster. And the reasoning behind it is so the weight is weighted propperly on the rope if the knot is facing the same direction it seems to sway to on side which allows for the twisting. It would be alot easyer to show then to discribe

[catbirdseat]

I've done practice on several occasions and never paid any attention to the direction of the knots. I've never noticed problems with twist in the rope either. The knot is loosened most easily using the thumbs, so I suppose that having them opposed would allow for each thumb to work best on the knot according to its orientation.

[Weekend_Climberz]

I prefer using a carabiner wrapped with the prussik rope through the gate several times. It's really super easy to work with when you got gloves on because the biner makes for a nice handle. Anyone else use this or reccommend against?

[jja]

I think the carabiner thing is better with one of those other friction knots, like a kleimheist.

[jhamaker]

>There's too much "lore" going around . . .<

 

 

Yes, it is called "experience.

 

 

>. . .w/o enough testing to back it up.<

 

Yes, if you want data and testing, get w/ the spelunkers.

 

For instance, they tested falling on prussics (sorry, no ref.) - and found that 10 out of 10 failures were because people grabbed onto the prussics knots durring a fall.

 

Opposed knots - do help reduce spinning in a free hanging situation.

 

I think the main point though is to *pay attention to details* - or it could kill you. Death of some very competent people has resulted from stuff like not doubling back the harness, keeping it too loose, or not verifying/testing anchors or not tying a 'stop knot' in the end of a rap rope.

 

 

 

[catbirdseat]

I prefer using a carabiner wrapped with the prussik rope through the gate several times. It's really super easy to work with when you got gloves on because the biner makes for a nice handle. Anyone else use this or reccommend against?

 

I believe the knot you describe is a Bachman knot and yes, it is a lot easier to slide along the rope, because of the "handle" formed by the carabiner.

[iain]

 

Yes, if you want data and testing, get w/ the spelunkers.

 

I do, and they prefer the term "caver". Sorry to invoke such a strong response! Just saying climbing is also full of a bunch of trivial stuff that can distract from what is important at times. I'm sick of debates over what core temp is considered advanced hypothermia, markers on ropes, etc, etc.

[obsydian]

Seems the most popular reason I've run across is rotation when ascending. We did 3 runs up a 12 foot section of rope, and here are the results:

1) both wrapped left - 1/3 turn

2) opposed - 3/4 turn

3) both wrapped right - 2/3 turn

 

We concluded that opposed or not doesn't make much or any difference in rotation, and it is clearly not a safety issue for anyone to concern themselves with. Thanks for all replies.

[Thinker]

I prefer using a carabiner wrapped with the prussik rope through the gate several times. It's really super easy to work with when you got gloves on because the biner makes for a nice handle. Anyone else use this or reccommend against?

 

Yeah, the bachman knot if fine. I wouldn't use it for glacier travel, though, because it's bulky, heavy, and the carabiner would tend to knock your teeth out in the event of a fall.

[remlec]

When I was taught this it was because the climber could put one hand on each knot and use his thumb to release the knot and slide it up thereby always having a hand on the rope. In practicality, almost everyone uses both hands to release the knot so the point is moot and the emphasis on opposed knots is now somewhat passe.