Question about scooter knot

When I started cave scootering I inquired into what knot to tie the tow rope on with. (How's that for ending a sentence with TWO prepositions?) It was unanimous - everybody said to use a Prusik knot. Since I was never a Boy Scout I didn't know how to tie one so I looked at a scooter and copied what was on it. Since then I've showed numerous cave divers how to tie one.

Or not. After reading a recent thread I've found out that's NOT a Prusik knot. It's a taut-line hitch. Look at these Wiki pages:

http://en.wikipedia.org/wiki/Taut-line_hitch#.231856 (Look at #1856)

http://en.wikipedia.org/wiki/Prusik

As you look at these pictures it's obvious that the taut-line hitch is nothing at all like a Prusik knot. Does anyone know the history of why virtually everybody calls it by the wrong name?

People tend to call anything a prusik that holds onto a running piece of line when loaded... In that respect, it is very much like a prusik, after all :-). In the same vein, when talking about mechanical SRT ascenders, many climbers and cavers use "Jumar" to mean any make of mechanical rope-gripping device.

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Originally Posted by Slüdge

When I started cave scootering I inquired into what knot to tie the tow rope on with. (How's that for ending a sentence with TWO prepositions?) It was unanimous - everybody said to use a Prusik knot. Since I was never a Boy Scout I didn't know how to tie one so I looked at a scooter and copied what was on it. Since then I've showed numerous cave divers how to tie one.

Or not. After reading a recent thread I've found out that's NOT a Prusik knot. It's a taut-line hitch. Look at these Wiki pages:

http://en.wikipedia.org/wiki/Taut-line_hitch#.231856 (Look at #1856)

http://en.wikipedia.org/wiki/Prusik

As you look at these pictures it's obvious that the taut-line hitch is nothing at all like a Prusik knot. Does anyone know the history of why virtually everybody calls it by the wrong name?

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Originally Posted by Michael Stroeck

People tend to call anything a prusik that holds onto a running piece of line when loaded... In that respect, it is very much like a prusik, after all :-). In the same vein, when talking about mechanical SRT ascenders, many climbers and cavers use "Jumar" to mean any make of mechanical rope-gripping device.

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Sort of like how most people refer to all facial tissues as "Kleenex" or all photocopies as "Xerox Copies."

Brian

I was never a Boy Scout either, but spent a good part of my life playing with ropes - as a firefighter-paramedic, mountaineer, ski patrolman, caver, etc. I have heard a lot of people use "prusik" as a general term to refer to any kind of a knot that uses the friction of rope wrapped tightly around rope. I learned the taut-line hitch and the Prusik as two separate knots, but used to hear all sorts of things called prusiks.

I learned the real Prusik loop in ski patrol as a substitute for ascenders in climbing up a rope. They were much lighter and (most importantly) cheaper than mechanical ascenders, and we used to carry three of them and some webbing in our patrol packs in case we had to climb up onto a chairlift. When I started caving and got some Gibbs ascenders, I forgot all about Prusiks!

Mike

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Originally Posted by Michael Stroeck

In the same vein, when talking about mechanical SRT ascenders, many climbers and cavers use "Jumar" to mean any make of mechanical rope-gripping device.

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You're right! But I would never call my Gibbs ascenders Jumars - they'd never forgive me! :)

Mike

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Originally Posted by MORGAN

You're right! But I would never call my Gibbs ascenders Jumars - they'd never forgive me! :)

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While we're off-topic, have a look at this ridiculously awesome website, which details probably 90% of all mechanical and non-mechanical ways and means of doing stuff with ropes known to man: http://storrick.cnchost.com/Vertical...icalHome.shtml

If you are talking about the knot used on the SS tow cords..... The story I heard from Wayne is that he show Rodney the knot. That it got put on all the SS tow cords. As for a name, I have no clue. As for a step by step on how to tie the knot, I posted this on DIR Explorers a long time ago.

http://www.direxplorers.com/speciali...ighlight=zeuxo

I posted step by step pictures of how to tie the knot.

Cheers!

Kevin

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Originally Posted by Michael Stroeck

While we're off-topic, have a look at this ridiculously awesome website, which details probably 90% of all mechanical and non-mechanical ways and means of doing stuff with ropes known to man: http://storrick.cnchost.com/Vertical...icalHome.shtml

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Thank You! That web site is amazing!

Mike

I picked up some rope from Wally world that seems to be too slick for any knot...

Get some good "4mm accessory cord" from REI or other outdoor / climbing stores. It's kernmantle and thus very durable and it makes great scooter tow rope. It will hold a Prusik knot very well, after all, that's what it's designed for.

It's available in a multitude of color combination's or plain old black if you prefer. Here is a link to some that REI stocks:

http://www.rei.com/product/767608

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Originally Posted by cavediver27

it makes great scooter tow rope.

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Or if you live next to a major army installation, ask any soldier to get you some parachute cord.

Better still, if you know anybody doing major goldline replacement, ask for a scrap piece about six feet long.

:rollguy

That would explain the change at Ginnie. Could do several scooters with what was removed past the Hinkle :)

Hadn't thought about parachute cord, I'll have to get that.

I would think a more static cord would be better than a thin dynamic cord like 550 paracord. I've never tried paracord, got to bet the scooter would feel like a yo-yo in you hand when you hit the trigger. I've always used 4mm climbing rope or some BS camping cordage that they sell at Ginnie.

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Originally Posted by caverkevin

The story I heard from Wayne is that he show Rodney the knot.

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I haven't heard that story, but Wayne showed me the knot, as well. He called it a Midshipman's Hitch, which is just an alternate name for the same or similar knots.

Prusik, Taut-line hitch, midshipman's hitch and others are all types of friction hitches, a knot that uses friction to hold its place on another rope yet can still be adjusted. A lot of people seem to use Prusik as an umbrella term for most kinds of friction hitches.

We had a big spool of parachute cord at the shop before we moved - I haven't seen it since. More than half of our instructors are military.

The parachute cord I have and the gold line I have seem to be identical except for color.

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Originally Posted by caverkevin

I would think a more static cord would be better than a thin dynamic cord like 550 paracord. I've never tried paracord, got to bet the scooter would feel like a yo-yo in you hand when you hit the trigger. I've always used 4mm climbing rope or some BS camping cordage that they sell at Ginnie.

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I agree, that's why I use 4mm accessory cord. Most of the 7-strand 550 para-cord available today is only 1/8" diameter and it does not hold a Prusik knot well.

I use a bowline with a lock-knot on both sides of the scooter.

Why use a sliding knot at all?

Mine is set up like a daisy chain. It has overhand knots about every 3 inches or so. It’s really easy to change which link you’re clipped into on the fly. Takes about 2 seconds. No slipping...ever, per the design. The problem w/ a prussic is that they release when not under tension. So you get it the way you want it, let go of the trigger, the knot releases, again, per design, you hit the trigger again and it slips.

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Originally Posted by jmaddox

Mine is set up like a daisy chain. It has overhand knots about every 3 inches or so. It’s really easy to change which link you’re clipped into on the fly. Takes about 2 seconds. No slipping...ever, per the design. The problem w/ a prussic is that they release when not under tension. So you get it the way you want it, let go of the trigger, the knot releases, again, per design, you hit the trigger again and it slips.

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It depends in part on how tightly you dress the knot and in part on the rope you use, with with a cord with enough friction (wet does not help here) and a knot that is properly dressed and snug, I have not had this issue.

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Originally Posted by Tegg

Why use a sliding knot at all?

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A related question / poll is:

Do you tie the boltsnap into the tow line, or leave it free to move back and forth on the tow line?

Talk to Wayne at Amigos, he knows knot all to well. :smt079

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Originally Posted by jmaddox

So you get it the way you want it, let go of the trigger, the knot releases, again, per design, you hit the trigger again and it slips.

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I agree with DA; I've never had a problem with one slipping.

In answer to Joe, sometimes, for some unknown reason, I like the tow rope longer than on other days. I can adjust the taut-line hitch while moving, either to shorten or lengthen it. And I let the bolt snap slide freely along the length of the rope.

Edit: Now that I think about it, I can lengthen it while moving but I have to be stopped to shorten it.

Not to go to far off topic from the original knot question...

This is the manner I have found that works good for me. YMMV.

The line is tied to a 1" stainless ring on either side of the DPV via two half hitches. I have a 1" stainless ring on the line that can slide freely. In order to adjust how close the DPV rides to me, I added the knotted line and made "loops" for my double-ender to clip into. This makes for easy adjustments when needed.