Tips and Tricks

Burrapeg

Been here a while
Location
Puget Sound
How the system works for the climber is the only accurate assessment of a climbing system. Calling it something else because it works differently in other applications is a 'yeah, but' and pointless argument.
Certainly it is largely pointless what we call some of this if it works, as long as it does not encourage any confusion somehow. I have still been using 'SRT' and 'DdRT' and I am told by some that these are obsolete and inaccurate terms now. And of course, we have whole threads here about what else they should be called. I believe most arguments of any kind are of the 'yeah, but' nature and often the only positive outcome is it encourages constructive thought on a subject by both parties. Now, one thing does occur to me about the 2:1/3:1 thing that may sometimes directly affect the climber himself if he is calling it one or the other, and that is a situation where to estimate the length f rope he is going to need in a given spot is critical. On a longer drop-down or longer limb walk where you have slapped on this pulley to add MA, if you don't have quite as much tail left as you would like, and are assuming this is going to be 2:1 when in fact you are using three times the rope, there could be a big difference in the amount of rope length you think you had available after you have dropped down any real distance. So, to recognize this as 3:1 rope use from the climber's position is certainly the only approach for the climber himself. At least twice I have done something like this thinking I had enough rope tail and ended up dangling short of where I was headed by quite a few feet and the stopper knot on the end in my hand!
 
So, to recognize this as 3:1 rope use from the climber's position is certainly the only approach for the climber himself. At least twice I have done something like this thinking I had enough rope tail and ended up dangling short of where I was headed by quite a few feet and the stopper knot on the end in my hand!
Great comment B: so for the shorty rope set esp. (say when travelling) - you go from lotsa (SRT) to not as much (DdRT), to maybe enough, maybe (using pulley or MA system say on a stem choke)! Have seen folks not ever bother tying in a stopper knot of some kind three or four feet from the end of their rope (F8 or whatever you feel is better) - maybe this is just a really cool habit to get into no matter your climbing system - just one less thing to fuss with or forget and it only takes <30 sec? A requirement for climbing comps?
And when buying your next rope(s) - if you only EVER use SRT - cool but what if . . . . . future possible systems in use influences rope length choice . . .
 
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Burrapeg

Been here a while
Location
Puget Sound
Great comment B: so for the shorty rope set esp. (say when travelling) - you go from lotsa (SRT) to not as much (DdRT), to maybe enough, maybe (using pulley or MA system say on a stem choke)! Have seen folks not ever bother tying in a stopper knot of some kind three or four feet from the end of their rope (F8 or whatever you fell is better) - maybe this is just a really cool habit to get into no matter your climbing system - just one less thing to fuss with or forget and it only takes <30 sec? A requirement for climbing comps?
And when buying your next rope(s) - if you only EVER use SRT - cool but what if . . . . . future possible systems in use influences rope length choice . . .
This may be the only area where what we call it does affect the climber himself! It was embarrassing both times when it happened to me, because I was in a group. And would have been a total PITA if I had let the tail end get away from me.
 

DSMc

Been here a while
Location
Montana
...
I have still been using 'SRT' and 'DdRT' and I am told by some that these are obsolete and inaccurate terms now...

I do hope you actually realize that what we are discussing is nothing like a changing acronym.

I am having trouble with your understanding of how much rope is used in each system, but still not accepting the face value of the numerical mechanical advantages. The amount of rope used per the moved object is a defining measure.
 

Burrapeg

Been here a while
Location
Puget Sound
I do hope you actually realize that what we are discussing is nothing like a changing acronym.

I am having trouble with your understanding of how much rope is used in each system, but still not accepting the face value of the numerical mechanical advantages. The amount of rope used per the moved object is a defining measure.
Well, I can try to further explain what I was getting at, if we are not drifting too far off topic to continue to discuss the tip shown in the drawing. Look at your own statement: 'the amount of rope used per moved object is a defining measure'. Fine, but this is true for either point of view and basically no help in deciding 2:1 or 3:1 if you leave it at that. If you want to ascend a given amount, you will use exactly the same total length of rope as the groundie would. How has your statement clarified anything? Us climbers will experience what seems like 3:1, the groundie sees it as only 2:1 but the same rope length passes the climber. Also, if you try to learn anything about pulley systems as a new climber, google around or open a textbook to see it is called 2:1 and they never make any distinction as to who is pulling on the rope. Talk to your own craneman or rigger, a seaman, a physics teacher, you will hear 2:1 for that drawing. The ONLY thing the climber does different with the rope length at all is he pulls several times the amount as a groundie would for the same rise in height. He just gets to spread it over several pulls of the same length as the groundie but each with correspondingly less force, raises only that smaller proportional amount each time, but he still moves the same exact total amount of rope past himself finally as the groundie would have, to move himself a given distance, if you want to define the mechanical advantage by only that. This is my only point, the possible vagueness that exists with our own form of the definition as climbers. Day to day, who cares? It all works fine, like magic, so no big deal, just intriguing stuff to consider and to keep in mind if, as a beginner, we try to learn about pulleys and MA from any expert source other than another climber. In this way, what we call it verbally IS similar to the same sort of confusion as if we use unfamiliar or changed acronyms.
 

Tuebor

Carpal tunnel level member
Location
Here
I still need some convincing. In test number one, the climber is pulling his entire total weight with gear (let's say 200 pounds) up the single SRT rope with each pull. Now in test number two, which is supposedly 2:1 now, he runs the rope thru a pulley and back to himself, exactly halving his weight across the pulley on each leg when at rest with no pulling to climb. 100 pounds on each leg, precisely, if we assume a frictionless pulley for now. Now he wants to ascend a bit and adds a little pull to the leg opposite the saddle leg to gain some height. Here is the thing troubling me: whether a single line for SRT or doubled back to himself for MRS, the TIP or TIP pulley still sees exactly the same total weight of climber and gear, or our 200 pounds, all the time. This is a constant and no pulling of any kind anywhere in the system can change that. Whatever he does, the rope will immediately move back and forth over the pulley to equalize. So, if he has real 2:1, and can pull, say, 30 pounds over and above the 100 pounds of half-weight that is always on that leg, so that he has gained twice that or 60 pounds of upward pull subtracted at the saddle from its 100 pounds, then we have an impossibility. He cannot under any circumstances add only 30 pounds down against 60 removed up. There is no '100 pounds lifting 200'. The two legs would not total 200 pounds at the TIP at that instance. What I think he is doing, that feels like great MA, is merely moving the same 30 pounds from the saddle over to the down leg by shifting his body weight over by hanging on the pull down. Thus, instead of feeling his entire 200 pounds as he rises, like on the single line in test one, he only feels the 30 pounds he has to add to one of the equal legs and subtract from the other at the saddle, to raise his 200 pounds. Ironically, this feels actually much greater than 2:1 with 30 applied to raise 200, but is really not MA at all. He has not actually divided the total force needed at all. You have 130 pounds suddenly on the down pull against 70 remaining at the saddle at that instant, he rises and removes some rope from the loop he is hanging on to capture the progress, and the total weight at the TIP has remained his same 200 pounds the whole time, 130 and 70 for an instant instead of the 100 and 100. He has pulled 30 to gain 30 at the saddle. The 60 total difference is just that, a difference, not a total gain. It is the same 30 pounds simply moved to the other leg. And the same amount of rope is actually used, not twice the rope. He moves twice the rope at his hands only because he is also the load and is rising past his own rope moving in the opposite direction. One foot of rope moving up matches one foot of rope headed over the pulley and back down to the ground. As I see it, we may have a neat trick by splitting the climber's weight equally between two legs over a pulley for basic MRS, but I don't see we have any actual MA for the whole work accomplished. He may indeed pull twice the rope with half the force as a groundie each time, to climb, but he is also only moving half the distance each pull that a groundie could give him. His two pulls equal the single one from a groundie, both in distance moved up and also in total rope usage. How is this actual 2:1, except merely seeming to be that at the climber's hands each pull, when in fact each of his pulls is only doing half the job. Further, this means the drawing, with its one single added layer of MA with the pulley moved from TIP to saddle, is just moving from 1:1 to 2:1, not 2:1 to 3:1. We ignore the added pulley up at the ascender since it is not adding more MA and only a 1:1 redirect back down from the TIP to the climber. It may feel 3:1 to the climber himself in the third test but have we really done 3:1 overall? Only twice the rope has moved to the ground, not three times, and he has risen half the distance of rope length used, not one third. The difference involves what the climber experiences against what he is actually accomplishing in the same motion. Consider a driver going 30 mph seeing a car pass him doing 30 the other way. They do indeed pass at 60 but how far has the driver himself actually moved along the road? Or a boat moving up a river to cover 10 miles, against fast river current flowing the other way at 10 mph. The boat has to do 20 mph thru 20 miles of the water moving past him to cover the same 10 of actual distance up the river. Their experiences are valid but are not a true reflection of what they are ultimately accomplishing if they have intended to move a certain distance. As far as I can recall, this is the substance of a discussion between a bunch of experts I was privy to hear at the Sedro Woolley twin-rope thing a few years ago. Mumford was one of the group and I think he could clarify this issue much better in a video (if he hasn't already!!!). The three tests above work as they are said to and felt very convincing to me when I have tried them at times, but don't really tell me the exact amount of mechanical advantage I actually gain.
The system is a gun tackle, except the climber is applying the force to the moving load (himself) changing it from a 2:1 to a 3:1.

I think you are mixing force and energy analysis. Mechanical advantage is a method of multiplying force. Lifting a climber to height changes his energy state (increases potential energy). It's done by applying force to the climber through the rope (and pulley). Applying that force to move the climber higher produces work which changes his energy state. A pulley is a simple machine that multiplies your force input - but slows your rate of doing work. With a 2:1 or 3:1 it takes less force but more time to produce the work of lifting the climber.

As to your analysis of the climber shifting his weight to lift himself on a 2:1 system: he is using the pulley as a fulcrum and the rope as a lever, like in a see-saw. By shifting his weight, he is putting a heavier kid on the other end of the see-saw.
 

Burrapeg

Been here a while
Location
Puget Sound
By shifting his weight, he is putting a heavier kid on the other end of the see-saw.
Right, Tuebor, but that heavier kid is a chunk of himself moved over, that is the thing. The weight of the new kid is subtracted from the first kid because it is the same kid just leaning over and hanging on the down pull. The weight of the total mess hanging at the TIP never changes. The fuzzy part to me. that you guys still fail to make clear to me, is how this stays 3:1. Look at the situation above in one of the posts, of a 150 pound climber hanging in that drawing, with 50 pounds on each three legs of rope. Two to the saddle pulley and one in his hand holding on. Okay 3:1 ratio right now, fine with that. BUT it is weight only; there is no MA happening. He is exercising no mechanical advantage at all right then, just hanging there at one point, same as if he tied the down pull to his saddle bridge. The three equal weights are hanging on the ropes to a single TIP but there is no upward force picking him up until he pulls harder on the down leg and begins to employ MA with that pull leg and it begins to move down. The three legs have stopped being a single tie point sharing three equal legs as long as it is moving. He clearly has to lean over and add to the 50 pounds on the down pull leg to go anywhere up. The entire affair still weighs 150 at the TIP above, so where does that added weight come from? There is no way he can add 10 or 20 pounds and lift 150. It is not 150 now at the saddle. He adds, say, 10 pounds of extra pull to try and ascend. 60 pounds now on the down leg, leaving 90 at the saddle. 60 plus 90 for 150 total TIP weight which can never change. You see where this going! He pulls 60 down and raises the 90 lbs remaining saddle weight? Maybe so. Maybe this is the magic I am missing, but it looks fishy and I don't see 3 to 1 now anywhere there is weight and force. Where is it? What does the rope used have to do with it? It's total stays the same anyway.
 

DSMc

Been here a while
Location
Montana
Burrapeg, your lost in your numbers and making assumptions based on your beliefs.

If you would just setup all 3 systems and climb up a ways, you would see it is not magic, just a simple truth that when the climber is doing the pulling, the math changes.
 

Burrapeg

Been here a while
Location
Puget Sound
Burrapeg, your lost in your numbers and making assumptions based on your beliefs.

If you would just setup all 3 systems and climb up a ways, you would see it is not magic, just a simple truth that when the climber is doing the pulling, the math changes.
I have done this a number of times and, yes, I feel the advantage just like the rest of you. I am just not sure it is 3 to 1. I use all three of these setups almost every time I climb. I almost always use both SRT and DdRT in a good climb and I carry that homebrew QuickRoll every single climb for just what the drawing shows. But I am a curious type and like to know why there seems to be a difference. I see the factors that don't change at all, like the total rope used, how much the climber moves for the amount of rope in total (these are not mere beliefs but witnessed fact), and I have a fuzzy time reconciling that with the simple truth that you and I feel. I am not disputing the math changes somehow. I feel it same as you. But I ask a specific question in that previous note. Can you tell me how?
 
I have done this a number of times and, yes, I feel the advantage just like the rest of you. I am just not sure it is 3 to 1. I use all three of these setups almost every time I climb. I almost always use both SRT and DdRT in a good climb and I carry that homebrew QuickRoll every single climb for just what the drawing shows. But I am a curious type and like to know why there seems to be a difference. I see the factors that don't change at all, like the total rope used, how much the climber moves for the amount of rope in total (these are not mere beliefs but witnessed fact), and I have a fuzzy time reconciling that with the simple truth that you and I feel. I am not disputing the math changes somehow. I feel it same as you. But I ask a specific question in that previous note. Can you tell me how?
You may be over-thinking this.
The idea behind mechanical advantage (leverage) is very simple.

Work = Force x Distance
or
Distance = Work ÷ Force
or
Force = Work ÷ Distance

That is:

To lift 100kg 1 foot (the work) you can

a) pull 1 foot of rope with 100kg of force

b) pull 2 feet of rope with 50kg of force

c) pull 4 feet of rope with 25kg of force
etc...

"Force multiplyer" is a misleading term because, of course, you cannot suddenly multiply your strength. What you can do is multiply the distance you apply that same strength and thereby accomplish an equivalent amount of work.
 

Burrapeg

Been here a while
Location
Puget Sound
OK, this is better, thanks Fulcrum. You are talking my language now. Equations and an exact answer are what I wanted to see, not vague assurances that it 'just works'. I am sure I have highjacked the thread long enough but I do appreciate the feedback, all of it. You guys know me, I have been on here for almost four years. I constantly build stuff; I don't just climb. Power ascenders half the size of a Wraptor, etc. that are midline attachable and work on any rope you shove in it. Other stuff too, my own versions of Bone, Wrench, etc. And gobs of other stuff having absolutely nothing to do with climbing. I have been a machinist, foundryman, and maker of stuff for over half a century. Guys like me just need to get all the way to the bottom of things if they don't seem quite right or are not obvious. We tend to apply this mindset to every single thing we do. We often do seriously over-think stuff, and on purpose. So, sorry if any of you found it tedious! Cheers, Stewart
 

Burrapeg

Been here a while
Location
Puget Sound
Tips and tricks-

If you avoid conversations about mechanical advantage in climbing systems, your wife won’t get mad at how much time you spend on treebuzz.
Boy, have I got something funny to tell you guys about that! Ellen (wife) went to the three day camping/climbing event with me, the one where we sat thru the talk on MA I mentioned with Mumford, Dave from WesSpur, etc. Now, even looking at these equations above, one can still wonder exactly what the real picture is, to actually visually see why it is different for the groundie. And it was her that told me! We were sitting in bed last night after that all this discussion and I visited with her about it since it was still on my mind. In the middle of talking about it, she remembered something I had not. She said, 'what about when they put the groundie up in the air?'. And of course that is the true picture! It is the 2:1 that does not actually exist! It is always 3:1 even with the groundie! And the cheating, magic part is we add a bit of weight to the groundie to keep him on the ground. In the drawing, if the groundie weighs exactly half what the climber weighs, that is the only way he can hang in the air and not drop. It looks like 2:1 when he stands on the ground but that is because we hand him a feather to overcome the friction in the pulleys! Without pulley friction, we could walk over and just touch him with a finger to move him up or down and the climber would move opposite. It looks like 2:1 but the groundie is always one third part of the load. He is one third of total load at the tip even when he is on the ground pulling; he simply always has added weight. You would never have a groundie lift a climber in the drawing if he weighed half or less what the climber weighs. If he weighs half, and you have friction less pulleys, he lifts both himself and the climber an equal amount, which is half what the climber would rise if you reach up and hold the groundie still, where he is hanging. This where we get an apparent 2:1 with a groundie. And it takes no extra force. We just cheat a bit and make him heavier all the time so only the climber part of the load rises and that is the only part we care about.
 

Burrapeg

Been here a while
Location
Puget Sound
Are you compelled to make this the most contorted, incomprehensible, never-ending discussion on climbing systems?

It's a climbing system! Stop bringing in groundies and magic.
Am I the only one here on the Buzz who has ever high-jacked a thread to clarify something? To discuss and analyze climbing systems is exactly what our TreeBuzz forum is in large part concerned with, isn't it? OK, so wrong thread right here, my apologies once again, in case you missed it the first time.
 

eyehearttrees

New member
Location
Tampa-Area
Went to a hands on splicing class, haven't paid money for a splice since. Only blood, sweat, and some tears.
Gotta say Samson's guides (written on their site & the corresponding Youtubes) were all I needed for nearly perfect splicing of an entire climbing & heavy-duty rigging kit....Combine this approach with Wesspur's clearance section and you can have a $1k "retail" rigging kit for well under half the price!

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Surely already said but APTA/air-cannons!!! Not an unknown tip/trick but will say it's been a game changer for me, more advantage from this 1 piece of gear than any other (by FAR)

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The "Treesqueeze" lanyard by Buckingham is a solid configuration, makes spurring-up safer & lets you climb around srt setting anchors on vertical stems w/o forks, but you don't have to pay $200 (of course) you can simply, say, take 20' of your favorite cordage, a friction hitch & some o-rings and now you've got an awesome "flipline/anchor lanyard"!!
 

rico

Been here a while
Location
redwoods
~~~~~~~~~~~~

Surely already said but APTA/air-cannons!!! Not an unknown tip/trick but will say it's been a game changer for me, more advantage from this 1 piece of gear than any other (by FAR)

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The APTA is one of the few tools that I can honestly say was a total game changer for me...Being able to set access lines in excess of 200 ft has made my life soooo much easier. Some of the best money I have ever spent on a piece of tree gear.
 

JeffGu

Been here a while
But my wife is a physicist...

Lucky guy. Your wife probably tries to tell you how the universe works. Mine is a chemist who now works in health care... she keeps telling me why I should not eat or drink whatever crap I'm indulging in at the moment. If I read the label out loud, she tells me what all those ingredients are. It's amazing how they can make snacks and beverages without having to actually harm any actual food.
 

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