Settling the Mechanical Advantage of the Trucker's Hitch

We examine the mechanical advantage of the trucker's hitch by analyzing the forces involved in the knot, and corroborating those results with experiments/measurements.
We also take a look at the 2:1 block and tackle, and a 2:1 winch/pulley (AKA Snatch Block) setup, to help explain why the mechanical advantage of the trucker's hitch is so often misunderstood.
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Related videos:
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► How to Tie a Basic Trucker's Hitch: • How to Tie a Trucker's...
► Mechanical Advantage of a Trucker's Hitch? (short): • Mechanical Advantage o...
#knot #tutorial #physics #mechanicalengineering #science #force #pulley #bushcraft #camping

[@UKscalemodeller]

Short, factual and to the point. A*

[@morganrademan1375]

So I agree that if the tree is treated as a pulley then it would be 3:1 advantage. But when you tie a ridgeline for a tarp with a tree as an anchor point, the rope doesnt rotate around the tree, making the whole system a single pulley system, i.e. a mechanical advantage of 2:1.
This also explains why your experiment gives a 3:1 advantage because when setting it up you allow the "tree" part of the system to move.

[@bushcrafted6726]

100%

[@74357175]

This is great! You can also do the calculation using the theoretical length change in the working loop: Imagine a loop of length 6 units (3 +3) and the working end at the pulley. If the working end is pulled 3 units to the tree, the rope will by definition be in a 2+2+2 'N' configuration that has pulled the pulley 1 unit closer. Hence 3 to 1

[@stealthypinecone3121]

Thank you for the knowledge!

[@SMart7751]

This is good. It had been confusing me, now I get it. Thanks!

[@canesser1]

Science! Great job as you made it easy to understand and prove. Tying off the pulley to the standing line seems to be the key.

[@thetautline]

Exactly! Using the second pulley adds *two more* tension forces from the input

[@haydenhowell1647]

What if you add another loop??

[@stephanddd]

Thank you! Now for a special request: can you help calculate the mech advantage with the Zombie hitch aka Transport hitch?

[@homoevolutus]

I need a playlist for all the comments!!!

[@danielmuller4829]

Thanks, that was really helpful. While this now makes the theory clear, can we have some "real life" mechanical advantage examples? Maybe a few typical examples with and without carabiner... Would also be curious how effective of a pulley a tree can be... If the rope doesn't slide at all around the tree, i guess we're back to 2:1 (considering the other pulley "ideal") ?

[@sandybil]

Hi, can i use engine hoist to pull a tree against the lean

[@thomasgronek6469]

Yes, the way you drew it, it is 3F. However, when one uses a trucker’s hitch, on a truck, the pulley on the tree doesn’t exist, that end is anchored to the truck, giving a 2F on the tie down line That might be where some folks went wrong. Thanks for the video.

[@mikedebell2242]

I usually tied off to one side of the load on my truck then pulled through a tie down point on the other side of the load then through the loop before tying down to the same point on that side. This would make that point another pulley and, seeing it was metal, less frictive than a tree.

[@skidjumper]

Still quite a bit of friction on the rope loop. An old timer arborist taught me that if you tie your loop using a bowline on a bight and make all the loops the same size the rope you pull through the three loops has a larger radius and gives a MUCH greater mechanical advantage.

[@TheShinayser]

Waiting for the same video but using 2 e 3 pulleys as you taught on the other vídeo. As you said it's 5:1 and 7:1 right?

[@daftTony]

3:1

[@sensorpixel]

Very nicely explained and demonstrated, kudos! Out of pure curiosity, do you have a background in science or engineering?

[@thetautline]

Engineering, you nailed it!

[@sensorpixel]

@@thetautline Haha, cool :) Physicist here, really enjoy your channel! Solid, non-bullshit information presented in a very clear and understandable manner, which is very refreshing. Greetings from Germany!

[@thetautline]

@@sensorpixel Awesome, thanks for watching!