ffj's journal II Rope Rescue Technician

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Re: ffj's journal II Rope Rescue Technician

Post by jacob »

What, no mention of how the rabbit comes up the hole and goes around the tree and down again? :geek: As far as I understand, fancy climbers can tie a bowline behind their back with one hand. If you're two-handed, get in the habit of forming the loop the same way all the time so the tree is always pointing up. That makes it a lot easier for the rabbit.

For sailing, the bowline is great because it's possible to untie by hand even after it's been under a ton of load. Headsails are tied with bowlines. (Wondering whether that's where the name came from?) Never had one of those come loose on it's own---guessing because they're under constant load. I have tried tying tarps with bowlines ... they did come loose---guessing because they got wind-flogged ... load on..off..on... off. No good.

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Ego
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Re: ffj's journal II Rope Rescue Technician

Post by Ego »

ffj wrote:
Tue Sep 05, 2017 11:59 am
It is also good to remember that tying knots in a rope will reduce its working capacity, so we want to ensure that the knot we use has been approved for rescue work and has been tied correctly. Knots are often rated for their efficiency, usually expressed as a percentage of the remaining strength of the rope. For example, if I were to tie a figure eight on a bight that has a 80% efficiency on a rope that has a MBS (minimum breaking strength) of 9,000 lbs, then my working capacity for that rope would have reduced to 7,200 lbs. Also keep in mind that most rope degrades over time, whether it is used often or not, and that sometimes it is better to reduce the working capacity even further due to degradation. Most nylon and polyester products have a working life of 10 years or less for life safety, and testing has proven that these products will degrade over time whether put into service or not, so even “brand new” rope will be weaker with age. Obviously, there are many factors to consider so a good rule of thumb to conservatively follow is to reduce the MBS by 50% anytime a knot is tied in a rope.

Nice project. I expect I am going to learn a lot.

Coupla questions....

I had to look it up to learn that climbing rope is rated in kilonewtons. So if I have a 9.2 kilonewton rope that's ten years old..... Using the google calculator 9.2 kilonewtons is 2068 pound force. Is pound force equal to working capacity?

And if so... if my friend was to tie an 80% efficiency bight using that ten year old rope and attach it to his climbing harness then.... 2068 X 50% =1034 X 80% = 827 pound force. If he's a big guy (250 pounds) and falls ten feet before I belay him, might he exceed the 827?

Thanks!

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Re: ffj's journal II Rope Rescue Technician

Post by McTrex »

What's a bight?

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Ego
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Re: ffj's journal II Rope Rescue Technician

Post by Ego »

ffj wrote:
Tue Sep 05, 2017 2:17 pm

@Ego

Excellent question and to be fair I'm going to dedicate an entire post to just your question because it encapsulates so many factors. I don't have time at the moment but hopefully tonight I will. That's kind of a neat problem to solve actually.
I realize it may be jumping ahead. If so, I can wait until you build up to it.

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Re: ffj's journal II Rope Rescue Technician

Post by 7Wannabe5 »

Neat project. A book written on a topic like this would likely hold its value within niche market for many years. I would pick it up at a dealer's sale without bothering to check current used retail. Hobbyists, and specialists, want to own every published book in their niche, and will hold on to them forever. Pay attention to your marketing, especially your cover art, don't print too many copies, (if any), be vigilant about plagiarists, and you will probably be able to count on a fairly steady, small passive income from sales as part of your retirement portfolio.

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Ego
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Re: ffj's journal II Rope Rescue Technician

Post by Ego »

Wow. This is certainly one of those areas where I learn a little and it reveals the staggering amount that I don't know. Thanks!

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Re: ffj's journal II Rope Rescue Technician

Post by FBeyer »

It's been a hobby of mine for a couple of months to practice some knots in the evening. I don't have anything sensible to add to the topic right now, I just wanted to chime in and tell you that I appreciate your efforts tremendously. I really do, and I'll definitely follow along.

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Re: ffj's journal II Rope Rescue Technician

Post by enigmaT120 »

Interesting thread. Will any of these knots prove useful for tying down objects to secure them, like the bow and stern lines of my kayak going to parts of my pickup? Those ropes do get some wind whip. I could see where the bow line would be good for attaching the rope to the kayak, (or is there a better one for that?) but I was more thinking about how to tie the other end while keeping the line under tension.

Sorry, I know your purpose is for rescue, but if some of the knots have other uses could you mention it?

Thanks

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Re: ffj's journal II Rope Rescue Technician

Post by jennypenny »

ffj wrote:
Sat Sep 09, 2017 11:24 am
Btw, if some of you are interested in buying quality rope for practice that will also handle a life load check out this website for arborists:

http://www.wesspur.com/index.html

Go to the tab "Specials" and then click clearance rope. All rope is new but of varied lengths as they are end of the spool off-lengths. Your can research the details of each rope type in the website. I would recommend getting a climbing line and not a rigging line. It's a cheap way to get started with quality rope.
What length of rope would be sufficient to try everything you're going to show us?

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

This is a fun topic!
For just practicing knots 10 to 15 feet is plenty but once I start showing anchor systems and mechanical advantage systems then you'll need more for sure. At the minimum I would say 30 feet but 50 feet would be ideal or you could always buy a standard length at 120 feet.
I suspect readers will be able to practice most of it with string or cheap clothesline type cord and a few keychain carabiners (though it won't be able to bear any weight). Harbor Freight is a good source for cheap rope for just practicing knots and rigging.

I posted a comment on this thread yesterday but it never showed up. Sorry if the following creates a duplicate post:
If someone is interested in learning rope rescue/climbing/rappelling I recommend that they take a class and practice a lot. Reading instructions on the internet is not enough. This is not a place to experiment to find out if something works or not, except I suppose if the victim is in imminent danger and there is no other rescue available. Even if you take a class don't assume you will remember it or be able to work it out during a stressful incident unless the methods are in muscle memory.

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

Suggestion for the water knot pictures: use two different colors of webbing to make it easier to understand what is going on.

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Re: ffj's journal II Rope Rescue Technician

Post by jacob »

For sailing, clove hitches are also used to quickly tie a boat to the dock cleats. So another fast way to do your second approach is to "flip the second loop around" [the second horn(*)] and pulling on the bight. This is useful when the boat is coming in under inertia (dropped sails, no engine) and the bowman has to jump off and stop the boat before it torpedoes the pier.

(*) Or in your case the end of the same pipe.

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Re: ffj's journal II Rope Rescue Technician

Post by FBeyer »

The clove hitch can easily be turned into a constrictor knot. So if you know how to tie the clove, you can easily get two uses out of it.
https://en.wikipedia.org/wiki/Constrictor_knot

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Re: ffj's journal II Rope Rescue Technician

Post by FBeyer »

The one thing I have the hardest time with, is remembering which knots to use when. As Jacob said you use a Bowline for something specific on a boat, but that's because the particular sail you keep taught with the bowline is under constant tension. There are a lot of quirks to remembering when to use what knot/hitch and I can't figure out the system.

I gather it's someting you learn experientially, but I'd really love if there was ANY kind of system to figuring out what goes where, and when.

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

I'm not sure about a grand unifying theory of knots but you can get training within a given context. For example, the knots ffj gave are enough for multi pitch rock climbing. If you went with an experienced partner a few times you could learn from them and know what to do in common situations. Then you could practice under their supervision and after a few times out you would know what to use where.

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

The piece of rope you've used there appears to be shorter than the usual 20 foot or so cordelette for climbing. Do you commonly carry a cordelette of this length for rescue purposes?

Why not a presewn sling? Why not a girth hitch?

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

Would you use the anchor pictured by itself for a rescue?

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

It's interesting comparing a rescue anchor to a "standard" climbing anchor. I would hang off that anchor too but if I saw someone top roping off of it they would get some suggestions on other ways to do it. From a climbing anchor perspective the problems are that it is only attached to one object (the tree), the rope is not redundant (one cut and it fails), the carabiner is not redundant (two reversed and opposed lockers are recommended), and the rope is pulling the carabiner in two different directions (barely).

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Re: ffj's journal II Rope Rescue Technician

Post by Sclass »

ffj wrote:
Tue Sep 12, 2017 12:36 pm
The Prusik

This knot is usually tied with a prussic loop. It also has a multitude of uses including belaying, ascending rope, progress capture device, or a simple rope grab. The loop is normally a smaller diameter cord or rope that is secured with a double fishermans knot, although there are variations to this rule
Great thread. I've been waiting for you to mention this knot. Any experience climbing with it? I've been fantasizing about climbing a very large tree at my mom's using the prusik knots on a climbing rope so I can trim the tree.

I have no mountain climbing experience but I was hoping to try climbing the tree in 10' increments to test the technique. I've seen special mechanical attachments that do this without knots and wonder is the prusik just for emergencies like a muenter/carabiner as a substitute for a rappelling figure 8 metal loop.

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Re: ffj's journal II Rope Rescue Technician

Post by Gilberto de Piento »

Rock climbers use the prusik to ascend ropes all the time, though it is inefficient compared to using mechanical devices such as ascenders. It is good practice to carry two prusik loops (plus slings and carabiners) so that a climber can ascend the rope if needed. The petzl tibloc is a popular piece of gear that can be used in place of the prusik, is more efficient, and still cheap.

I really don't think anyone should start from a place of no knowledge about climbing and go straight to ascending a large tree to trim it, sorry. There's just too much that could go wrong.

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