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PostPosted: May 14th, 2008, 9:12 pm 
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Joined: July 22nd, 2002, 7:00 pm
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good info
thanks
ted

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PostPosted: May 14th, 2008, 10:28 pm 
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Hi Pat,

I am not trying to criticize. All I am saying is that you have to be mindful of how much force your rescue system can actually put on the boat.

With super strong rope and 3:1 or 4:1 grab its really easy to overpower, when what is really needed is less power and more finess.


Another issue with the really thin prussiks is that they can jam in pulleys. Many pulleys have shoulders designed to slide the prussik knot down the line. With the thin diameter ropes you need another set of hands in the danger zone to work the prussik.

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PostPosted: May 15th, 2008, 1:25 am 
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Thanks Dan. Can't argue with anything you've contributed (unless you try to save me with a 1/4" poly rope full of knots with no 'biners or pulleys). Nothing taken as criticism, and nothing meant to be defensive or as criticism - just good learin' (and I'd rather get here than on the river!).

Don't forget to call for a paddle when you're next in Vancouver!

Cheers, Pat.

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PostPosted: May 15th, 2008, 7:33 am 
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"Another issue with the really thin prussiks is that they can jam in pulleys. Many pulleys have shoulders designed to slide the prussik knot down the line. With the thin diameter ropes you need another set of hands in the danger zone to work the prussik."

- or - just use a "Bachman Knot" at the first pulley. It is essentially functions as a one-way prussic, or like a ratchet - the biner should be big enough to "jam" against the pulley which releases the grab on the rope.


and to answer a question posed elsewhere, about using webbing loops instead of accessory cord for prussics, look up "Kliemhiest Knot"

I've used the Bachman Knot in rescue practices - should work with most pulleys - the main reason for using it was that we were just using biners for pulleys, and the Bachman Knot is easier to use, to jam against the pulley biner - should work better with an actual pulley.


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PostPosted: May 15th, 2008, 7:53 am 
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Pat,

Thanks for this.

Lots to think about.
We've been tripping for almost 30 years, mostly unaccompanied, and aside from the throw rope, the only thing in my pin kit are syringes.

It sounds like the pin kit is utilized by an untrapped boat to rescue to a less fortunate companion. What if you're the only boat in the river? Is there a rescue course for this option?

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 Post subject:
PostPosted: May 15th, 2008, 8:27 am 
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Ted asked ?

"I'm now using 3/8 spectra thanks to Alan's recommendation.

If/when Z-dragging and I need to join primary ropes, should I be using a double-fisherman's or a figure eight? With or without stoppers?

"I have 1inch webbing looped with a water-knot to make an anchor.
Should the knot be changed to a double fisherman's with stoppers? Should I forget about the webbing and replace with 3/8 spectra?

I have 1/4 inch Spectra for prusiks as they are doubled. Joined with double fisherman's knots no stoppers.

I have 4 19.6Kn pulleys and 18Kn Black-Diamond oval biners.
Thinking of switching to inexpensive 23Kn wire gates.

Final questions:
How much gear/rope should be replaced after a high-strain rescue. I would think the prusik rope at a minimum as they were bent 90 degrees over the biner. But what about the anchor webbing or the primary rope? "

Here'e my take on those questions:
Joining two ropes is best done with a figure 8 - it is the easiest of the basic knots to untie after it has been used. If you have doubts about the strength of those ropes, use an overhand followthrough (a.k.a "water knot" ) to joint the two. A water knot is stronger, in that it weakens the rope (i.e. reduces the tensile stringth less) less than a figure eight knot- just forget about ever untying it. A properly tied 8 does not need a stopper knot - just leave 4 inch tails or more, so you can see that the ends aren't slipping. If that knot ever slipped, it would have to be using some really peculiar rope.

Re the 1" webbing loop, I'd stick with a water knot, and be sure that it also has tails 4 inches long so you can easily see that the tail isn't slipping through the knot. Reason I'd stick with a water knot is that is is easier to untie than a double fisherman;s knot, and you will most likely want to untie the loop to use it by retieing around a tree. A water knot in webbing will slip as it is being weighted and unweighted, a small amount each time. Always keep that in mind, and be sure that the tails are visible before you use it. I have seen multiple cases of webbing loops used for climbing where the tail is about to disappear into the water knot - trust me, it slips over time- but it is still the better knot to use in my opinion.

The strength of a prussic loop is about equal to or slightly greater than 100%
of the tensile strength (and I assume the same for dynamic strength) of the material used. You are pulling on two strands of the material, so its 2 X rated strength, but reduced by the weakness inherant in the knot. Generally any knot reduces a ropes strenght to about 2/3 at the low end - depends o the knot. A water knot joining two ropes is stronger setup thatn a figure 8. It does vary a bit depending on materials and diameters. So in short, if you are happy with the rated strength of your prussic material, you don't need to go to a larger diameter.

Any climbin gbiner is plenty strong enough for river rescue - as Dan pointed out, the boat is the weakest link.

I wouldn't bother to replace any gear unless it looks to have been frayed or damaged. To check your prussics, or any kernmantle type of rope or cord, you need to put in under tension, and feel with your fingers all along the length, feeling for spots with a lesser daimeter - if the rope is thinner, then some of the interior strands have broken and it needs replacing. The exterior of a kernmantle rope is there to protect the interior, and adds only marginally to the total strength. Alternatively, if I had any doubts at all about the throw rope, Id get a new one.

One thing I do not understand at all is why people rely on thier throw ropes as a primary rescue rope? They were never meant for that, are mostly too short to be practical, and mostly are not strong enough. When I go on easy river trips, Class 1, my pin kit is always in the dry bag with my change of clothes - its not ever a question of should I have it. If I go on CII or above, I add the 45 meter static/rescue rope. Even that seems short for many of the rivers I do, if a boat gets pinned mid-river. When I did the upper Missinaibi R solo a couple of year's ago - I carried that rescue rope and pin kit with me, regardless of weight and bulk - anything less would have been a joke. The static line fits into my dry bag, and that fits even in my WW boat. If I were to do any river above C1 that I couldn't walk back to civilization from in a day, I'd be bringing my static line.


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 Post subject:
PostPosted: May 15th, 2008, 9:07 am 
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good stuff,
Actually klemheists are my usual rather than prusiks.

I never thought about the possibility of jamming the slider rope into the anchor pulley before. I've always put somebody in the danger zone keeping an eye on the sliders. Good food for thought.

I think I'll pratice a bit with a Bachman for the first slider. I'm just a bit surprised that a Backman will grab like a klemheist/prusik as you'd think that the biner would be slippery.

We now run separate throw bags and Z-drag kits. The personal throw bags are 50foot 1/4 inch. The Z-drags are 75 feet of 3/8 in a bag with the hardware and premade klemheist loops. By doubling up the 1/4 when needed I figured we'd have enough.

Here's hoping it's never needed but it's fun to practise.

cheers Ted

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 Post subject:
PostPosted: May 15th, 2008, 9:30 am 
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Quote:
Here's hoping it's never needed but it's fun to practise


I'll bring my kit this weekend and we can, just practise that is. :wink:

It could be fun to see who in our group can actually use a throw bag. 8)

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 Post subject:
PostPosted: May 15th, 2008, 11:15 am 
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Pat,

Thanks for this.

Up until now my pin kit has consisted of a 50’ throw rope and if accessible another 50’ of tarp rope. We’ve been paddling, mostly downhill and mostly unaccompanied for almost thirty years.
I sounds like the pin kit is used by people to rescue a less fortunate boat and/or person of their group.
Is there a rescue course available for the situation where you’re the only boat in the river?

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 Post subject: single classes
PostPosted: May 15th, 2008, 11:41 am 
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Joined: June 23rd, 2006, 4:25 pm
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Location: Milton
Contact your local groups responsible for running the courses.
If not contact the organizer or instructor and see what you can arrange.
Or contact
http://www.solotripping.com/
and see what they do.
Doing this for 30 years and not got into trouble proves you got good avoidance skills and a good pinch of commonsense.
And that is what was lacking from most of the people I have "helped"
And like in the first post of this....
#@$% happens.
And to be in a group that knows what to do...
priceless.
Jeff


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 Post subject:
PostPosted: May 15th, 2008, 9:08 pm 
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Rick wrote:
I'll bring my kit this weekend and we can, just practise that is.

Good idea, when I try doing my self-rescue experiments and fail, everyone can take turns throwing safety ropes at me - no rocks in the throwing bags allowed btw.

It'll be good to meet up again this weekend.

cheers Ted

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 Post subject:
PostPosted: May 15th, 2008, 9:28 pm 
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Joined: April 14th, 2004, 4:26 pm
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Location: Toronto
y'all are coming to palmer fest?

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