# Two Knots for Mechanical Advantage

Update: After several readers requested further explanation of the mechanical advantage, I posted Physics of the Trucker’s Hitch.

The Trucker’s Hitch is not a single knot, but a knot system that acts like a block and tackle for tightening, hoisting, or hauling loads with mechanical advantage. You’re probably familiar with it, but it’s time to learn a couple of knots that will make this system easy to untie when you’re done, so you don’t have to cut the knot or waste time struggling to untie it. Review your knotting terms in last week’s Survival Tips article, which covers the Pipe Hitch and the Pile Hitch.

Watch the video for instructions (goes live early afternoon Jan 28).

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## Mechanical Advantage of the Trucker’s Hitch

I need to make a correction. In the video I said that the Trucker’s Hitch creates a 2-to-1 theoretical mechanical advantage, but in the specific configuration demonstrated, it’s actually a 3-to-1 advantage, because both ends of the system are anchored (like when tightening down a load in your pickup truck), which is how you will usually use it. If only one end is anchored, (like when hoisting a zombie up into a tree), that’s when you get only a 2-to-1 advantage.

Fig. 1 — Hoisting a Zombie. In this configuration, you gain a 2-to-1 theoretical mechanical advantage

In Figure 1, the first “pulley” is the midline loop, and the second is the Zombie’s neck. The second pulley is not fixed: it moves during the work done, and so you only get a 2-to-1 mechanical advantage.

Fig. 2 — Stretching a Zombie. In this configuration with BOTH pulleys fixed, you get a 3-to-1 mechanical advantage.

Figure 2 illustrates how the Trucker’s Hitch usually operates, as when securing a load in your truck or trailer. This is the configuration demonstrated in the video. Here both pulleys are fixed, and you gain a 3-to-1 mechanical advantage. So if you want to stretch a zombie apart, this is how to do it.

## Details about the Trucker’s Hitch

When securing a load in the bed of your truck or trailer, the mechanical advantage provided by the Trucker’s Hitch acts like a block and tackle, which allows you to tighten the rope a lot more than you can without it. You can tie the Trucker’s Hitch with several different combinations of knots, but I prefer knots that are easy to untie when I’m done. For the anchor I use the aptly-named Anchor Hitch, and for the midline loop I use an Alpine Butterfly.

The mechanical advantage (whether 3-to-1 or 2-to-1 depending on configuration) is “theoretical” because of friction. In a frictionless setup, all of the force exerted on your end of the rope goes into work on the load. But in the real world we have friction, which “intercepts” some of the work and dissipates it as heat, sound, and degradation of the material (“wear and tear”). Pulleys reduce friction and so are much more efficient. The slicker your rope, the better your advantage.

## The Anchor Hitch

This is my go-to knot for securing the end of a rope to a ring, post, or tree branch. No matter how much tension you put on the knot, it is easily cast off when you’re done. I’ve never had it jam or capsize.

Fig. 3 — The Anchor Hitch

## The Alpine Butterfly

This one is used for the midline loop (the substitute pulley). In the past, you’ve probably made your midline loop with an overhand knot, and then had to cut the rope or twine because it jammed. Those days are over. Once you learn this knot, you’ll never go back to the overhand. It is not as easily cast off as the Anchor Hitch, but with a little work wiggling the loops on either side of the knot, I’ve always been able to work it loose. Using a very thin twine under great tension, I can imagine a jammed Alpine Butterfly, but that’s an unusual case.

Fig. 4 — Front of the Alpine Butterfly. Note that the two in-line strands are parallel — they do not cross in the front.

To ensure the knot is easy to untie, you have to work the two in-line strands so they’re parallel in the front and cross in the back. If they cross in the front, the knot can jam, and I’ve heard it can capsize, but I haven’t confirmed that.

Fig. 5 — Back of the Alpine Butterfly. The strands cross in the back.

This photo shows the in-line strands correctly crossing in the back.

Practice these knots as demonstrated in the video, and see if you can get them tied in three seconds or less (each, of course!).

~SnoMan

### 6 thoughts on “Two Knots for Mechanical Advantage”

1. I love that Truckers Hitch, when I’m not using it to tie up Zombies, I really like to use it to keep my Canoe from flying off the top of my truck. That’s a fantastic Knot. Thanks for the write up!

2. Truckers hitch? I’ve always heard it called the “Oklahoma come-a-long.” And, there are easier ways to make it work than shown here.

1. Easier to tie, perhaps, but are they as easy to UN-tie as these knots are? That’s part of the point here, after all.

3. Great tip on the Alpine Butterfly loop, used it this weekend with the Trucker’s Hitch for my ridgeline for my tarp, worked great and came out very easily when breaking down.

4. Once you learn to do the trucker’s hitch, its 2:1 mechanical advantage makes the Taught line hitch obsolete.

I use the Bowline on a Bight on Monday & Tuesday, Figure-8 Wednesday & Thursday, and the Alpine Butterfly is reserved for weekends. Why you ask… so I don’t forget how to tie all of them.

SnoMan, Your Anchor Hitch reminds me it’s my primary end-of-line tie off to my carabiners and rope clips and that I need to mix it up with Buntline and Triple Fishermans.

If you never do vertical high angle work or have to secure a load to a pickup truck or trailer this stuff may seem like incomprehensible gibberish.

When you’re up on a tower, a cliff, in a tree, or stranded up on a fully extended malfunctioning manlift or bucket truck and you need to rappel down or modify your work positioning, fall restraint or fall arrest system, hoping you tied everything correctly is not a comforting feeling. Practice and repetition very well may save your life or somebody you care about — F the zombies.

It’ll come in handy too when you gotta get that Kitchen table home from IKEA on the roof of your Toyota Corolla.

Additionally, If your friend is hanging dead from Orthostatic Intolerance Suspension Trauma you can use the Trucker’s Hitch mechanical advantage to take the tension off his lifeline while you transfer his weight to a lowering line. Be kind to his family. Simply cutting his line and letting him drop to the ground precludes open casket viewing.

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