What makes you think it's being used by the government???

@@Tanglerwr lol lah.elearningontario.ca/CMS/public/exported_courses/SPH4C/exported/SPH4CU04/SPH4CU04/SPH4CU04A02/_content.html This is their official site I think in Canada Ontario and they used it for their physics course for pulleys. XD

How about that! And, THANKS!

This is a great video,

Thank you - and I am still alive! :)

@@Tanglerwr Any time I introduce mechanical advantage into a system that lowers the tension at the input. With this knowledge I can apply it to my real life situation. Let's say I'm in a Jeep Comanche and my buddy got his big heavy full size diesel truck stuck in the mud or on an incline. My little Jeep with little winch could safely recovery that heavier vehicle without dragging me nor without the need to anchor myself. I have safety and reliability as long as I respect my tensions at all points and consider the load limits of my gear. 😉👌 This is hugely important so I don't snap a winch cable, break a D ring, break a hitch/bumper, or burn up a winch. Please correct me if I'm wrong.

@@xmo552 All the mechanical advantage will do is lower the force on the cables. But, in the case of the Comanche and big truck, mechanical advantage will not lower the force on the bumpers, UNLESS a snatch block is used at the big truck AND the end of the cable is tied to something other than your Comanche. If the cable is run through a snatch block at the big truck and back to your Comanche, mechanical advantage will not reduce the pull force on the bumper of either truck. For example, let's say it would take 2,000 lbs to pull the big truck. We use a snatch block at the big truck with the end of the cable brought back to the Comanche and tied to the bumper. The pull cable on the winch would be reduced to 1000 lbs. The force in the cable would be 1000 lbs, but the force on your Comanche bumper would be 2000 lbs and the big truck's bumper as well. Let's do the same thing but tie the end of the cable to a big tree instead of to the Comanche. In this case, the force on the Comanche is only 1,000 lbs, but the force on the bumper of the big truck is still 2,000 lbs.

@@Tanglerwr Thanks. I follow what you're saying so far, but what if I set it up as a 3:1, 4:1, or 6:1? That's more of the situation I meant to say. What if my whole intent is to pull a big load while being light myself and not being anchored? Let's pretend I'm at a beach or there aren't any trees around or I simply forgot all my gear to anchor down and I've got no chocks.... just for discussion. All I brought along is a winch, alot of cable, and a bunch of snatch blocks. (By using let's say a 5:1) Could I pull an extremely heavy load without causing myself to slide along? No anchor and no tree. Just my four tires' traction holding me in place.

@@xmo552 Given those conditions, your vehicle will experience whatever force is required to pull the heavy load. The mechanical advantage won't reduce the force on your vehicle. Imagine you tie five ropes from your vehicle to the heavy load. Each rope will have (in theory) 1/5 of the load, but your vehicle and the load will both experience the full force required to do the pulling.

Jc Knight Haha no shit haha

Sir, I need some help. My Dad in his 80's mom in her 80's. Dad can't stand. Mom can't lift him. Think Block and Tackle could help but need at least 6:1 gain. Bought a 4:1 but the pulley drag was terrible. Can you recommend a product that might help?

Tanglerwr I've just checked most of the places in Sydney Australia where I thought I'd be able too get a similar system. Which apparently is not the case. I find it very strangely interesting this the system you have in this video does not seem to be available here in Australia. Thanks for posting the video mate. It's great. Cheers.

+Sunny Jim Ahhh the good ol days. My dad had a block and tackle that he strung fence wire with too. I used it for other things - grin...

Actually, just re-read another thread below and this has already been covered. I will let my comment stand though, because that other one may be too heavy going for some readers.

Yep to all of that! In fact since I have a safety knot in the pull line, if I release that line the knot would automatically tie off the system and there would then be 100 lbs on the anchor.

i just secured a 8:1 block and tackle micro block setup by viadana i need to do some rigging and it would take me 28# to pulley myself up each time it includes a v jam cleat in the design thinking of using some para cord or dyneema

Twisted rope is really bad about twisting. Using braided rope should eliminate the twisting.

Yes, this configuration can help with any lifting/puling task. Typically, the better the pulleys, the higher the effective efficiency, i.e. mechanical advantage. When low cost pulleys are used, a lot of the mechanical advantage is lost in friction. Can't help with a video you asked about, but a tip is try to pull against the load instead of the anchor - you're gain MA that way.

The lower red piece and the upper blue piece are called rigging plates. I got them at On Rope 1, onrope1.com/rescue-gear-accessories/petzl-paw-rigging-plate-medium/ and onrope1.com/rescue-gear-accessories/petzl-paw-rigging-plate-small/.

Rigging plates.

You are correct that the lines are carrying 1/4 the weight of the load - 25 lbs. But that's only for the configuration where the pull is against the anchor. For the inverted configuration, that is the pull against the load, the very system that was a 4:1 becomes a 5:1 and now the force is each line is 1/5 the weight of the load or 20 lbs.

+Brian Manthé Well, it is usually easier to pull downward than upward since you can use your body weight to help instead of stressing the back pulling upward, so the added pulley should be a big help.

Cats Life in bb

As much as I like rope and pulleys, in this case, I think a small winch would be better. The winch will have plenty of MA, in fact, you may have to shop around for one that doesn't have so much, but the big thing about the winch is it's lock and hold ratchet. If you are cranking up and lose control, the winch won't drop the load - if the ratchet lock is in place. The tricky part of a winch would be in the lowering process. When lowering, the ratchet action would be disengaged to allow the rope/cable to unspool. If one loses control lowering, it might not be possible to catch the load. There are some small electric winches that might work better than a manual winch. They pretty much pull and release and stop when you need them to.

I might can help, but I'm not familiar with the term "rope pump". Is that just the rope you use to lift the container of water? I'll need to know the weight of water you need to lift and how much force you can pull with.

I might can help with that :) The knots at the carabiner are a double overhand loop knot. There may be some other names for the knot but that will bring up the knot with a search. The knot I'm using as a pull/stopper knot is a safety knot. It's just a "backward" slip knot.

Using the info from this video, I actually built an elevator that I could use to lift myself to the second floor. I only rode in it once - as a test - because it had no safety features. But I used it many times to haul material up and it never failed.

zzimbo I believe that's 8 mm. I got it from On Rope - the store is 10 miles from my house, but they are online too.

@@Tanglerwr Hmm On Rope is On Line? At a minimum that's a double entendre! Lol possibly a 3:1 entendre :-) Sorry, if I have BELAY-bored the point.

That's a rigging plate. There's a small red rigging plate at the bottom as well.

I'm having to answer this without the benefit of seeing the actual setup and it all depends on the system. For example, if the overhead pulley is just a single pulley and the load is essentially directly under the pulley and you then pull the rope at a 45° angle, IF the pulley is free to swing, the pulley will locate at about a 22.5° angle because that would be the angle of the resultant force of the load and force in the pull rope. If the pulley system is more than a 1:1 MA, there will be less force in the pull rope and the pulley will swing less off vertical. The pulley will not absorb any more energy and the force you have to pull with will be about the same as the weight of the load. I.e. if you are lifting a 50 lb load via a single pulley and are pulley at a 45° angle, you will have to exert a force of 50 lbs - that neglects frictional losses.

Well I intended it to be similar to your video, a Block n Tackle where I'd be lifting something so heavy it would need 4 parts line to be 4:1 in a simply system. So pulling the rope in that situation would react how? Assume for example I'm lifting 400lbs, hence the need for 4 lines. Thanks

The upper pulley, the one at the anchor, will move slightly toward you. Neglecting friction, you will be pulling with about 100 lbs. It would be just as efficient to you as pulling straight down. Is that what you were looking for?

Understood, thanks very much for your time.

You betcha - glad I could answer your question.

Thanks much! I hope you and the kids enjoy exploring with pulleys. I bought most of my pulleys at On Rope 1

+Jules Bartow Ha ha - I'll use camo colors the next time! :) Your right, the math is pretty easy when everything approximates straight pulls.

Jules Bartow a

Most of it came from On Rope. The On Rope shop is 10 miles from my house!

What are you confused about?

Theoretically the diameter of the pulley sheaves do NOT affect MA, but in reality smaller diameter pulleys can be less efficient which can change the effective mechanical advantage, but then the same is true for ball bearing pulleys vs bushing type pulleys.

+Jacob Kamphus To my understanding it will not have any impact on the mechanical advantage of moving a load. The only aspect that would change is the number of rotations made by the pulley when pulling a given length of rope through it.

+Sam Swihart NO

The diameter should be large enough to allow the rope to bend without too much added resistance. Large diameter increases weight and occuppies the space. You have to choose something in between.

@@vojtechkment2956 and small diameter pulleys can increase the stress on the rope.

You are correct. A 5:1 operated "backwards" (actually a 1:5) would give you a 20# pull with a 100# weight. But, a 1:5 would not reduce the fall to 3 feet; it would only reduce 23 feet to 4.6 feet (23 / 5 = 4.6). A 6:1 would give you pretty close to the fall of 3 feet but you would need a 120# weight. Plus, you should add about 20% to that weight to allow for frictional losses in that many pulleys. A triple sheave would be needed at the weight and a double sheave at a fixed point above the pull point of the clock.

Tanglerwr Thanks you have eased my brain. The other limitations, not mentioned, would be the the strength of the support frame of the clock, that might not properly support the the clock, both time and strike weights(both 100#) and the impossibility of the weigh being more that a 3' fall. When you want a clock with a 4' winding height , in your den, and you don't want to stand on a ladder to wind...... there are limitations. Perhaps a 3 or 4 day run will be acceptable vs an 8 day run/23' fall. I have considered a change of weight form, cylinder to mushroom shape, (low profile) to gain a few more hours, but a 6: 1 might be impossible in this case , again, support strength of frame. We horologists use different terminology with fall but the results are the same, Thanks again for your help.

It might be a luff if used in sailing applications, but block and tackle is the more general name.

Hey J.D. Sorry to be so slow getting back to you. Those things you asked about are called rigging plates. They come in small, medium, and large sizes. The ones in the video at the top are the medium size. There's a small red rigging plate at the bottom. I didn't get to confirm this, but I'm pretty sure the ones I'm using are made by Petzl. However, there seems to be an explosion of rigging blocks in the market now by a lot of manufacturers. Some make a "3-D" type where the ones I'm using in the vid are a 2-D type.

Tanglerwr SIR, I HAVE A BLOCK & TACKLE THAT WAS GIVEN TO ME AND I BELIEVE IT IS THREADED INCORRECTLY. AND I BELIEVE THE ROPE SIZE IT TOO LARGE FOR THE PULLEYS. ANYWAY I CAN SEND TO YOU A PICTURE OF IT, SO THAT YOU CAN THEN TELL ME HOW TO CORRECTLY THREAD IT? THANKS IN TEXAS.

Tip Harris Send me a private message with your email and I can email you, then you can email the pic to me.

Tanglerwr this site gives everyone access to my email. got another address that I can use?

Tip Harris

Thank you for your comment, but no, the load isn't doubled. It would be if we used a single pulley at the anchor. In that case, the load would be pulling downward with it's weight and we would be pulling downward with a force equal to the load's weight and then the load on the anchor would be doubled. But in the block and tackle shown in the video, the anchor has to support the weight of the load plus the force in the rope we are pulling on. However because the mechanical advantage of the block and tackle is 4:1, we only have to pull with a force of 1/4 the weight of the load. So the loading on the anchor is the load weight plus 1/4 the load's weight.

I should have watched your excellent videos before asking that question. Unless I use these systems frequently I'm not likely to retain most of your information. But they're(videos) there if I need them. Thank you for taking the time to explain the pulley. There should be classes in the basics of applied and redirected force in high school.

Ronnie Teekel Great questions. If I understand this... Let's start with a a pulley anchored to a tree and your winch cable is run through the pulley and back to your bumper. That would produce a theoretical 2:1 MA. Now, if you disconnect the cable from your bumper and attach another pulley to your bumper and run the cable through that pulley and back to the tree OR to the first pulley, you now have a theoretical 3:1 MA. That brings us to your second comment, and this is the one I'm not quite sure what you mean, but...If you bring the cable that runs through the pulley at the bumper back to a second tree, and assuming you have reasonably parallel lines, you still have a theoretical 3:1 MA.

Ronnie Teekel LOL - I guess we see why they say a picture is worth a 1000 words! You're gonna have to help me out a little more - I'm still not quite clear what the exact configuration is. You have the winch line running from your Jeep through a pulley on the stuck vehicle and the line comes back to the Jeep - here's where it gets a little foggy. if you run the return line through a pulley and back to the stuck vehicle, you have a 3:1 as you stated. If you remove the pulley from your Jeep and attach it to a tree near the Jeep, it is still a 3:1 (the end of the line tied to the stuck vehicle). Did I understand you correctly???

Ronnie Teekel A redirect is a pulley that simply redirects the pull direction. A redirect pulley cannot move as the load is moved. The redirect pulley is connected to an anchor point. For example, imagine you have a stuck vehicle and your Jeep is on solid ground beside the stuck vehicle and hence you have no way to pull directly. So you run your winch line through a pulley attached to a tree inline with the vehicle and attach the end of the line to the stuck vehicle. That's a redirect and it's 1:1. The pulley doesn't move, it is tied to an anchor point and all it provides is a way to change the direction of pull.

Tanglerwr video

Tanglerwr t

Tanglerwr thanks so much. Wand what about the double pulley in the left that you use to make the block and tackle?

@@racerx1326 I believe those are SMC pulleys. Wow! pulley prices have gone up a lot since I made this video! www.wesspur.com/pulleys/SMC-pulleys.html

@@Tanglerwr Thank you very much for these explanations of pulleys. Really helps me to get to grips with the princeples.

Yes, it's true. Obviously the anchor has to support the full load because we aren't supporting any of it in the original orientation of the pulley system. So, in addition to the full weight of the load, we, as the puller, are pulling down against the anchor by the tension in the pull line. Let's take a very simple example, a single pulley attached to an overhead anchor point. We have a rope through the pulley with one end tied to a 10 lb load and we're holding the other end of the rope. Because the tension in the rope is equal there is 10 lbs from the load pulling downward and we're pulling downward with 10 lbs also. The two loads add i.e. 10 from the load plus 10 from our pull line. The sum is 20 pounds and that's what the anchor has to support. In the case of the 4:1 the pull line will only have 1/4 of the load, so the additional force against the anchor is the full load weight plus the pull rope force. So for a 100 lb load (just for easy math) the anchor has to support the load, 100 lbs, plus our force on the pull line which is 1/4 of the load's weight or 25 lbs. So, adding the load, 100 lbs and the pull force of 25 lbs we get 125 lbs at the anchor.

@@Tanglerwr Very nice, ty for the reply. I had initially thought it was 200% but then realized that it wouldve started to move much sooner. I really love physics and you do a great job of thoroughly explaining those concepts. That is sure to get more people interested in physics :)

I just put mouse to MS Paint shop and drew it out. Best I can tell is the locking point (fixed point) is attached to the same pulley you pull from. The load pulley is attached to the load and ropes goes up to the pulling pulley from fixed point on load pulley then back down to the pulley on load then back up to the pulling pulley then out to power (human, dog, car, cat what ever is pulling load). Should be able to use this design no matter how many pulleys are used as long as both blocks have same number of pulleys each. Another important fact to consider, know the load limit of the rope. I have to load a 750 lb pop machine. I don't want to use a rope with a limit of 150 lbs. I hope this was helpful after 3 months.

Richard Britt Just a couple of comments. You are correct that you can add pulleys, however there will be a point of diminishing return. In the real world, pulleys have friction so the theoretical and actual gain is different. If you add enough pulleys, friction can offset the mechanical advantage. So it can look like we have a 12 to 1 that may only be a 6:1 effectively due to friction. Second is the rope strength. If you're lifting 750 lbs, you probably need a mechanical advantage of about 10:1. That means, disregarding friction, you will have to pull with 75 lbs to lift 750 lbs. That means each strand of rope in the pulley system will only have to support 75 lbs. However, there's that nasty real-world friction thing. 90% efficient pulleys would reduce the effective mechanical advantage of the 10:1 to 5.9:1. 95% efficient pulleys would give an effective mechanical advantage of about 7.6:1 So if you combine too many pulleys, you can wind up with a system that is very ineffective - just something to keep in mind.

So what is your thoughts if I am only pulling the soda machine up a ramp? I'm hoping the pulley system will be same as adding a few people. Would I only need about 200 lbs limit?

Richard Britt Hmmm, I bet I missed the 'up a ramp' part - Ramps can lighten the load significantly. E.g. if you're on a 30° ramp with a 750 lb machine, you will only have to pull with 375 lbs (half it's weight) to get it up the ramp ASSUMING very little friction on the ramp - i.e. the machine is on rollers. If you're dragging the machine without rollers, friction will make the job a lot tougher. Generally the fewer pulleys you can use the better off you'll be, so you would want to use a pulley system that gives the MA you need without the accumulative friction a simple block and tackle would have. Unfortunately, the more efficient arrangements are more complicated to set up and have other issues as well. A small cable come-along or boat winch might serve you better - just depends on the specifics of the application, i.e. ramp angle, ramp-machine friction, etc.

Sorry, my bad. Yes there is a ramp and it is about 30 deg. angle. We will have it on a Utility dolley with a kick out set of wheels and it will be rolling up backwards. My neighbor thinks we could put a set of jacks under it and raise the ramp up but I'm thinking it would be an accident waiting to happen. 750 lbs raised up on 2 jacks, if one leaked a little tilting the machine and bang, down it would go. I good idea but I think I'll stick with block and tackle. Would love to see the math you used to come up with the rope limits. I can get 150 feet of 450 lbs. rope. That should do the trick. I'll have to have someone video the loading so we can post it. Be a hoot as long as it didn't fall. Thanks for your help.

You have the pull weight correct, but the rope length will have to be 2500 feet. The four load strands are 500 feet each, then the pull rope is another 500 feet. I'm assuming your pulling from the bottom, i.e. where the load sets before it's raised.

@@Tanglerwr 500' of 3/8" guy wire cable is going to be stretched tight from tree to tree at a decline. The object will be attached to guy wire from the top tree. Block and tackle will be attached to top tree and object on guy wire. Object will be let down to bottom tree and then raised back up along guy wire to the top tree via blocks and tackle. I will be operating this from the top tree

@@JasonAlexzander1q47 Ahhh, in that case you are right about the rope length. But, a weight supported on a guy wire is a very different situation than a 600 lb deadlift. While the load is 600 lb, if the guy wire is on an incline, the actual load you have to pull will be dependent on the incline. Let's say the guy wire is perfectly level. The entire weight of the 600 lb load is supported by the guy wire. To move the load you only have to overcome rolling friction in the pulley(s) supporting the 600 lbs. If the incline is 45°, neglecting friction for the moment, the load you have to lift will be about 420 lbs. If the incline is 60° you will have to lift about 520 lbs. If the incline is 75° you will have to lift about 580 lbs. Your actual pull force would be the load divided by 4 plus some additional force to overcome the friction in then pulleys. However, since you are pulling from the top, i.e. pulling the load up to you, you can reverse the pulleys and gain another unit of mechanical advantage. But then you'll need 2500 feet of rope in that configuration.

Reverse it?

@@JasonAlexzander1q47 I explain the reverse in the video starting about the 4:00 mark.

Just a residential address - I'll take another look at the PM thing as soon as I catch some free time - shortly I hope.

Tip Harris I just sent a message to you. Go to your channel and click on the ABOUT tab and see if you see a message.

+Benjamin Cant There is no error; there is no exponential exertion force - this is all static, nothing is moving so all forces are static. The forces will not be exponential even in a dynamic mode. Write out the equations for dynamics, i.e. f = m*a. That's the only force created by exertion and as you can see, it is not exponential. Both the static and dynamic forces are affected by the orientation of the pulley system. When the pulling force is directed toward the anchor the system shown has a 4:1 and the anchor will experience a force of 120 lbs; 100 lbs from the load plus 20 more pounds from the pull line. When inverted it becomes a 5:1 because the pulling force is toward the load. In this orientation, the anchor will experience only 80 lbs because the pull rope is supporting 20 lbs of the 100 lb load. Check this out in some books. On Rope and Life on a Line both give an excellent coverage of pulley systems and loading calculations.

+Tanglerwr My bad, I should never have said 'exponential force'. My understanding is that when the down line/loose line is being pulled through or hauled, there is a reduced factor of force being exerted upon the primary anchor point to the price of 4:1. However when the down line is not under tension, ie when the load is not being raised, the sum of the load rests upon the primary anchor point. The mechanical advantage does not eliminate any force when no mechanics are being employed.

+Benjamin Cant Still there is no bad error in the video. There is no error at all. I did not include load or progress capturing in this segment in order to focus on mechanical advantage and anchor loading and illustrate the differences due to pulley system orientation. It is true when the load is supported by a progress capturing device that anchor loading for the normal orientation, i.e. 4:1, is the same as the load. But as soon as one starts to move the load, or if the load becomes supported by the pull line, e.g. the load is supported by tying off the pull line to a fixed ground referenced object, all the force considerations I talked about in the video apply. In the case of the 4:1 the anchor loading increases by 20%. It’s a little different for the inverted orientation. Again, if progress capturing is employed, the anchor experiences the weight of the load. But as soon as one starts to move the load, or if the load becomes supported by the pull line, e.g. the load is supported by tying off the pull line to a fixed ground referenced object, all the force considerations I talked about in the video apply. In the case of the 5:1, inverted, the anchor loading decreases by 20%.

This may have been uploaded when KZfaq was going through some issues. I had to reload several vids because of KZfaq issues. Although, as I watch the video above, the focus is not HD, but it seems pretty much on par with other vids at 480p. It may be a combination of the video resolution, KZfaq rendering, and it could be your eyes are changing with age. This has been viewed over 220,000 times and this hasn't been mentioned before.

I'm workin' on it. It used to be easy to send personal or private messages - now I seem to be having a hard time figuring out how to do that???

thanks

Tip Harris hmmm, I posted a comment here and it's not here??? Anyway, I may have been successful sending you a private message. Go to your channel and click on the ABOUT tab - hopefully there's a message there.

I do, but getting it to you it is the problem. We used to be able to send PMs to do this kind of thing. I'm reluctant to post my email here.

All he had to do was click on the Send Message button on your ABOUT page.

That's a new one for me. If the load is being pulled straight up it will never be moving horizontal to the Earth's surface unless a side force moves it sideways. Even then there will be no gained mechanical advantage. Maybe what you read was referring to a particular configuration, for example where the load is being pulled up a ramp, or a load being pulled along a horizontal surface. The ramp itself provides a mechanical advantage and if a pulley system is also used they would both provide mechanical advantage.

@@Tanglerwr The ramp, along with the Pulley, are two of the six (6) "Classical Simple Machines" wherein a ramp is called the "Inclined Plane". The 5 remaining are: Lever, Wheel & Axle, Pulley, Wedge and Screw. Although, there are modern-day arguments that the Wheel & Axle are actually the Pulley. As well, there are frequent discussions about the similarities of the Wedge to the Ramp, and that the Screw uses an Inclined Plane. Additional information can be found at: en.m.wikipedia.org/wiki/Simple_machine

Leszek, Tanglerwr is correct, although it is hard to put a finger on why. Many advise the rule of thumb to count the number of ropes shortened, rather than number of pulleys. When the block and tackle on the left was inverted, how did it change? This is where Tanglerwr's rule of thumb helps: how many ropes support the load? His hand is bearing some weight of the load! A share equal to all the other ropes! One fifth, to be exact! If there was one more pulley on top to let him change direction and put his weight into it, we could see that five ropes would be shortened, yielding the same ratio of five to one. Many thanks to Tanglerwr for showing this to me!

Safety is my first concern in any lifting application, I guess you noticed how many cautionary comments I make in my pulley videos. First, if you use a prusik, it has to be "tended", I.e. you need to watch the prusik to be sure it catches the rope properly. Next, prusik cordage needs to be kept clean. Stains etc. on the cover are not a problem. But, when dirt, debris, mud, etc. get inside the prusik cordage, the cordage becomes less supple or stiffer and it tends not to hold securely. So pursiks need to be kept clean or they should be replaced if there is any doubt as to their integrity. One test for a prusik is to form a loop in the cordage. If a really tight loop can be formed, the prusik is probably good to go. If the cordage feels stiffer and will not make a tight loop, it should not be used. The prusik cordage has to be sized to the haul rope. Generally, you used cordage about three millimeters smaller than the haul rope. E.g. In the video you linked, I was using 11 mm rope and 8mm prusik cordage. Also, the prusik is NOT a brake or release control. If you try to control the lowering of a load with the prusik, it will likely overheat and melt and fail. I guess you can see why I put in so many cautionary comments in my pulley videos - there's a lot to consider that isn't included in the vids. That's why I recommend attending an appropriate training class for your application. Lastly, you may want to consider using a winch instead of the pulley system. Winches have drawbacks too, so again - training.

Many thanks, I chose to use the pulley system rather than a winch as it could reduce the load when lifting. What could be used instead of the prusik as an adequate a brake or release control?

Richard Aina There is a 'family' of devices that could be used, but when used on the pull line of a pulley system, the security of the brake/lock could be compromised, plus they have to be used as a pulley themselves and they make a very inefficient pulley. But they are commonly used in lifting, holding, and lowering applications and are designed for that. The devices are, Petzl Grigri, Petzl Rig, Petzl ID - these are all designed to use as both a catch and brakeand for lowering a load. Unfortunately, these things are pricey.

Okay, as you said the best thing to use would be a winch. Would that be a winch on the end of a pulley. With the winch being able to optionally stop reverse motion?

Similar workings to the devices mentioned above. If so that'd be ideal.

Everything I said prior to and at the 2:04 mark is correct and accurate. What specifically is it you think is wrong? Could it be you are confusing that the rotation of the sheaves can be different within the double pulley but the double pulley itself moves toward the load and hence both sheaves or pulleys move toward the load at the same speed?

@@Tanglerwr I believe the questioner was thinking of rotational speed of the pulleys themselves. And, of course the rotational speed of each individual pulley would be different (by the same ratio as the force multiplier). However, He/she must NOT have heard you QUALIFY your statement; "... all the pulleys have to move, at the same rate of speed, TOWARD THE ANCHOR."

Pulley sizes can make a difference in efficiency of the system, but using pulleys of different sizes won't create mechanical advantage. That would work with gears, sprockets, and belt driven pulleys.

@@Tanglerwr I don’t understand the difference. It works with a bicycle. You switch gears in a ten speed and the pedals turn faster in relationship to the rear tire. And yes you can change a blower speed by adjusting the sheave of the drive pulley, or changing the size of the wheel pulley. I know you can even overload a motor by putting too large a pulley on it so why does this not work when pulling something with a rope?

@@brianlittle717 I'll have to get back to you tomorrow about that.

@@Tanglerwr yeah I’m just thinking out loud. The rope being pulled across the large pulley will cause the pulley to rotate more slowly than a small pulley. So there must be a mechanical advantage if the configuration is in the correct order. I have no way to test this at the moment.

@@Tanglerwr I think I figured it out. If you pulled one foot of rope out and the object moved one foot, that’s a 1-1 ratio. Changing the size of the pulley would still yield a 1-1 maybe? But why does it work on the 10 speed bicycle? Maybe because it’s a fixed length of chain?

Tip Harris OK, do this: go to canopy chatter - www.treeclimbercoalition.org/ and register. Once you're registered, you can send me a PM and I can send you an emai address!!!