Unassisted Mast Climbing using an GriGri with voice over.
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- Опубліковано 22 сер 2024
- Using a GriGri to climb a mast. This is a voice over of my other video. It is otherwise the same.
Please visit L-36.com/more_... for details on the method. Please be advised that this is a bit complicated and I do not recommend it and no longer use it myself. Please see • Ultimate Unassisted Ma... for the method I use now.
I am amazed that people who should know better do not understand the mechanical advantage of a pulley system. Not just the commenter below but even a physics professor I know! There are simple rules. "Count the number of lines that get shorter". In the case of this system count the number of lines that are holding you up. There are three. Two to the GriGri and one in the hand of the climber. Each line has 1/3 the climber's weight so the system is 3:1. But the efficiency depends on friction and the GriGri has a lot of friction. I measured the friction at about 60% so roughly the system has about the same net advantage as a 2:1 system even though it is 3:1. How about that for confusing it even more? Regardless, It is easier than the standard 1:1 methods.
Thank you for this video which allowed me to perform my first climb to the mast of my sailboat today to recover the recalcitrant wifi weather vane. thank you for the explanations, the pedagogy and also the quality of the images. A French yachtsman based in Port Leucate (Occitania, Mediterranean)
Thank you for sharing this! I've been a rock climber many years and knew I could apply this to climbing a mast on my boat. The pulley is a nice extra touch there giving a bit of a mechanical advantage. Well thought out.
Thank you for your comment. As an experienced rock climber you would have the knowledge of the equipment required to make this a reasonable system to use. Best of luck. I just added the link to the article in the description and below.
L-36.com/more_mast_climbing.php.
"Klemheist" was the name you were looking for, similar to a Prusik, but not 😁
Great and encouraging explanation of using your GriGri, and ascender combination.. Thank you!
Each of your mast climbing videos shows me something new. Here I learned about some of the idiosyncrasies of the Grigri. That was very useful for me. Thank you for posting.
Thanks for the thorough informative video ! Been trying to figure out a better system to get me up out of the caves, I appreciate that I can also now repurpose my grigri 😉 till now it’s been a great paperweight. I’ll try to get some trial footage of me using this system on my harvestore and posting it. Thanks Ciao !!
Live video, like the honesty.
Thank you.
The longer the tail of the bowline doesn't mean its safer. If the coller on the bowline gets too big somehow the nipping loop can capsize turning into a slip knot, the long tail wont help it will just slip out
I think the bigger risk with a bowline is for people who do not know how to tie one and tie it wrong. I tried just now to tie one very lose and made it collapse. It slipped but slipped toward the shackle just making it tighter against the shackle. It did not slip toward the tail. I was unable to make it slip as you are describing. Rock climbers don't necessarily know how to tie a bowling so a figure of eight is safer. If you are climbing a sailboat mast, you are very likely to know how to tie a bowline. I started mast climbing using a figure of eight but it is just so hard to untie. But if you are uncomfortable with a bowline, use a figure of eight.
I believe the knot you're using in place of a prussik knot is called a "klemheist" knot.
You are right of course. Thanks for the clarification.
Great video, very informative and to the point. I tried this after watching another video last sunday. Other than getting bruises on legs and a huge one on my arm I managed it. My concern was too many lines that interrupted with my Gri-gri, to the point it lifted up the lever as I was ascending. I like the use of your pulley giving that 1:3 advantage but after reading some comments in the other video, is this not dangerous? The line going out of the Gri gri shouldn't it be facing downwards to create a lock? Taking it up to the pulley makes it dangerous since the Gri gri is not engaged. Would like your comments on this. PS I had one foot loop and as I am not a climber it became more difficult to stand after a while, so will go and get a second foot loop. Again thanks for a great video.
I can't say I understand your questions fully. I can't imagine how the line to the pully would interact with the handle unless you strung it wrong. The handle goes off to the left and the pully is on the right. The GriGri should stay in the closed position all the way up.
But that said, this method is just too complicated and too easy to string something wrong which mostly you don't find out until you are at the top. I no longer like it and don't use it. I use the one I call the Ultimate Mast Climbing method linked in the comments. Just click "More" above or go to L-36.com and look under articles. Here is the link l-36.com/UltimateMastClimbing.php. That method is also complicated but I have not found it prone to rigging incorrectly. I keep major parts rigged in my storage bag to remind me how it all goes together and even after a couple of years I just rigged it and climbed my mast a couple of months ago without needing to read or watch anything.
I noticed that some place you mentioned "100% redundant". This is certainly not that. That is because the entire system depends on the red climbing line up to the top block on the mast, and whatever the blue/ white line is and is attached to.
The ONLY way this would be "100%" would be to incorporate some sort of harness/ strap/ other braking device TO THE MAST for fall protection. Incidently, part of my job back in the 90's was climbing a few communications towers. There has been a number of falls and deaths because of various failures, including a CLIMBING PEG on a Rohn free standing tower. Even tower safety cable/ braking systems are somewhat questionable, because you don't know what condition the hardware/ cable is in UP AT THE TOP, until/ if you "get there" At least on towers you can "hook up" on the way up
There are two climbing lines. One to my bosun chair and one to my harness. Plus lately I have been tying my chair to my harness, just a bit more redundancy. I have two wing halyards and one line is on each of them. Like I said, 100% redundant.
This certainly IS that! He's climbing on the red halyard, with a safety off to his white/green halyard! Maybe you should watch a little closer before offering "correction".
Thanks for the great video, I like this method and I find it very easy, even if some practice is needed with grigri. I have a question: in the unlucky event the main line fails, how can you come down just using the safety line, as prusik is so tight? Won't you need someone to unwind the safety line from down below? Thanks.
Great question. What you do is you wrap the line over one foot and stand on that foot with the other foot. That pinches the line between your two feet. Then you can stand up and release some of the tension on the prusick and slide it down. It is a fairly standard way to climb with a prusik although I can't find a video on it for you. The other way would be to bring another ascender and a sling and use that as the foot loop. You could also use a loop and make a second prusik for your feet. I personally would use the foot method and have practiced it and it works.
Here is a video showing the foot grab. In this video, he doesn't even have a prusik but you can see the foot technique. ua-cam.com/video/ROpnzuaaa1g/v-deo.html
You mention the harness or bosun's chair can't come out of the carabiner when you open it due to the pressure from your weight. To remove any possible risk, why not feed the downwards line coming from your micro pulley thru the carabiner before you start to climb, and just remove the pulley when at the top? I guess there's a chance you could drop the pulley or carabiner when taking them off the line to store on your harness.
There are lots of way to rig it for sure but opening the carabiner just isn't an issue for me. I am backed up by the safety line and the open carabiner is rated at something like 15KN which is about 3000 pounds. Compare that to a high quality bosun's chair which is rated at 220 pounds. Now one is breaking and one is safe but even with a 5:1 safety factor the open carabiner is safe to 3x the Harken chair.
If you really don't want to open the carabiner, just feed the rope through it and pull it all through. It is only 50 feet of rope and if you are worried about it, just do it that way.
But as I said in the comment below, I don't recommend this method. It is just too complicated and too many things to remember and rig. Use the two ascender with the rescucender on top. That is what I have on my boat in case I have to climb the mast in a hurry. video:://ua-cam.com/video/rjjY_XoxA5U/v-deo.html
Website L-36.com/mast_climbing.php
I am a bit puzzled as to why you didn't just use two ascenders instead of this rig, that is the standard technique rock climbers use to climb vertical ropes. You mention that the pulley system is 3:1, (really 2:1) but that is really not relevant since you should be climbing with your legs, not your arms. Using two ascenders both ascenders are engaged with the rope while you are lifting your body with your legs creating the maximum force on the rope, while with this technique only the ascender is engaged as you pull the rope through the grigri while standing up. Grigris are not intended to be used as stand alone autoblock devices while ascenders are. In addition to being more complicated and less safe, this setup is also more expensive than using a pair of ascenders. I would suggest using a cam based ascender such as the rescuecender as your backup rather than an autoblock hitch. A double fishermen knot in the end of your rope is a more reliable stopper knot than a figure 8 knot. Climbers typically tie double fishermen at the ends of their ropes when rapelling instead of figure 8's for this reason.
You are describing the method I recommend. I use a microascender or rescuascender and a basic ascender below it for the foot loops. It is a lot simpler and does not require reconfiguration at the top or all the tricks I show in this video. As I said, I do not recommend this method although I do use it. It is 3:1 because the climber goes up. If the same line is pulled from the ground, it would be 2:1. That is a common mistake in determining the purchase of a pulley system. More on both these topics on my website.
L-36.com
@@L-36 The Ideal Mechanical Advantage (IMA) of the pulley system is 2. You are incorrectly treating the rope that the person is pulling on as exerting a lifting force on the person which it does not do. The IMA (not purchase) is the ratio of the force applied to the rope to the force applied by the pulley system. It is also the ratio of the distance the rope moves down to the distance the distance the pulley and person move up. When the rope goes down 2 ft the person goes up 1 foot. The work (force x distance) that is done by the person's arm on the rope is equal to the work that the pulley does on the person (by conservation of energy) and the force that the bottom pulley exerts on the person is therefore double the force of the hand on the rope. This can also be seen from the fact that if the pulleys are frictionless the tension will be the same in all segments of the rope and the two ropes passing through the pulley attached to the person pull up with twice the force that is applied by the hand. The IMA is therefore 2. You make a common mistake in determining the IMA of a pulley system of this type of ignoring the fact that there is a distributed force involved in the person's arm contracting, and by treating the force on the person's hand as a force that is lifting the person. It is not. The person's hand does experience an upwards force AS IT MOVES DOWN, so while the force is upwards, it does not actually lift the person. Further since the displacement of the hand (down) and the direction of the force on the hand(up) are opposite, the rope is actually doing negative work on the person's arm. What does provide an upwards force on the person's body is the other end of the person's arm where it connects to the torso. As they contract and shorten, the arm muscles do positive work on both the rope as it is pulled down 2 feet and the torso as it is pulled up 1 foot. Since the forces on either end of the arm are roughly equal and opposite* the arm does twice as much work on the rope as it does on the torso. Both the rope and the person's body are applying forces opposite to the displacement of the point of application, doing negative work to (absorbing energy from) the arm. This energy comes from the chemical energy transformed when the person's muscles contract. In your model where the end of the rope is doing positive work on the person to pull them up, where do you think the energy is coming from? The rope? To understand this more clearly draw yourself a free body diagram of the person and the arm as separate objects. It is necessary to do this because the arm changes shape as its muscles contract while the rest of the person's body stays relatively rigid. There are three forces on the person's body: The downward force of gravity on the person, the upward force of the pulley on the person and the upward force of the arm on the person. The force of the pulley and the force of the arm thus both do positive work to the person's body as the points where they are applied move up. The arm experiences an upward force from the rope and a downward force from the person, and a relatively small force of gravity on its own mass*. The person end of the arm moves up and the rope end of the arm moves down so negative work is done to both ends of the arm. In the end all this is really irrelevant, because the person should not be lifting themselves by pulling on the rope in the first place. They should be using their much stronger leg muscles to lift their body and their arms just to stabilize themselves.
@@dwes3824 Wow, you are making this way to complicated. I agree on the legs providing a lot of the force but in reality this is less than you might think but let me just clear up the mechanical advantage issue of this system.
Consider the situation where the pulley is 1 foot above the climber. There is 1 foot of rope coming down from the ascender to the climber, 1 foot of rope from the climber to the pulley and 1 foot of rope from the pulley to the hand of the climber. When the climber pulls the rope and gets to the pulley, there is no rope from the ascender to the climber, no rope from the climber to the pulley and no rope from the pulley to the climber's hand. The climber moved up 1 foot by pulling down on 3 feet of rope. It is 3:1. Now consider if the same rope was fed down to a person on the ground. He would have to pull enough rope to pull the climber up 1 foot shortening the rope from the ascender to the climber by 1 foot, and one foot of rope from the climber to the pulley. Thus he pulls 2 feet of rope to lift the climber 1 foot and the system is 2:1. Same system but if the climber does the pulling it is 3:1 and if someone on the ground does the pulling it is 2:1.
It is probably easier to see this if you had a single pulley at the masthead and a line down to the climber. Someone on the ground has no mechanical advantage, when the climber is at the top, he has pulled mast height of rope to get him there. 1:1. But if the climber is doing the pulling, he starts with two mast lengths of rope and ends with no rope between himself and the masthead. He has pulled two mast lengths of rope to go up one mast height. 2:1. Same setup, different mechanical advantage depending on how is doing the pulling.
I hope this makes it clear. If not, try this. Again with a single pulley at the top. If the climber is holding the rope and weighs 200 pounds, each end of the rope has 100 pounds on it. 2:1. If a person on the ground is holding the rope there is only one rope going to the climber so each rope has 200 pounds on it. 1:1.
All this is under ideal conditions and there is friction in the GriGri so some of the force is lost to friction so the actual mechanical advantage is probably closer to 2.5:1 although I have not measured it.
What I can tell you is that the system I recommend, which is what you described, it more difficult to use going up and almost infinitely more difficult to use going down. But it also has the advantage that you can go back up a bit. I used it when I painted my mast as I could go back up a bit to catch that spot I missed. It is also less complicated and and easier to set up. Going down with the GriGri is easy and with the tricks in this video, very controlled.
@@L-36 Allen this statement "The climber moved up 1 foot by pulling down on 3 feet of rope" is objectively false. When the pulley rises 1 foot, 2 feet of rope are taken out of the two supportive strands of the pulley system, they go over the top pulley and down allowing the climber's hand to move down two feet relative to the pulley. Don't take my word for it go measure it. That is the beauty of science. You may be confusing motion relative to the climber's moving body with motion relative to the fixed pulley which is the critical issue.
@@L-36 To better understand what is happening here, consider the process of doing a pull up. Your arm flexes and lifts your body from the shoulder. While there is an upwards force on your hand, your hand does not move and does not actually lift, your arm does the lifting. When people who do not have sufficient upper body strength to do a pull up want to develop the skill they will sometimes use a large rubber band as a stirrup and do a pull up with an assist from the elastic force of the rubber band. That is a good analogy to what is happening here. The climber is doing an assisted pullup as they flex their arm. The assist comes from pulling down on the 2:1 pullley system instead of the rubber band.