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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#knot #tutorial #physics #mechanicalengineering #science #force #pulley #bushcraft #camping

[morganrademan]

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.

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

[canesser]

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.

[SMart]

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

[elcuentahistorias]

Wouldn't it be easier if you use 2 portable luggage scales? Just attach those to both ends and if you have 1kg in one and 2-3 in the other, you can determine exactly how much mechanical advantage considering even the friction, although that is valid only for that system specifically, still it give us a closer approximation

[stephanddd]

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

[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?

[danielmuller]

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

[RollingEasy]

Between the dark pulley and the arrow on the tail, put another rope eye with a shackle. Go around the tree again and then return to this shackle and pull the end another time. This is what I do. I did measure the total advantage as being 6:1.

[sensorpixel]

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

[thomasgronek]

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.

[homoevolutus]

I need a playlist for all the comments!!!

[BABLA]

I like to tie a theoretical 5:1 truckers hitch in most scenarios... Basically it's the standard truckers hitch + running the working end through and additional loop on the standing end. This is a super effective way to tighten down loads for transport on car roofs and trailers.