Sunday, 11 October 2009

TRUCKER'S HITCH

Use this knot when you need to tighten a rope to hold something down like a tarpaulin or to secure items in the back of a truck. I used three to hitch up and tether down my rain gutter. Click on images for larger images.




This knot can also be used as a crude pulley system with a 3:1 advantage if you ignore the massive amount of friction. I did this when I hitched up the HPS light in my growroom.

There are a few versions of the trucker's hitch, all of which are concerned with how the loop in pic. #3 is formed. One version uses a figure-of-eight loop, another uses a slipknot. I prefer this version because it's easier to untie. There's no knot to jam, the twist simply untwists when you untie it.

4 comments:

  1. If you ignore the massive amount of friction (which it has, yes!),
    the structure is 3:1. From the formed eye in the line, each of the
    down->up->backdown lines bears tension against the one line
    going away from the eye. (But in rope-through-rope, the actual
    mechanical advantage might be about 1.5:1.)

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  2. Yes, you're right. It is 3:1. The advantage of a trucker's hitch was a bit of a brain-twister for me for a while. Seems obvious now. Will edit.

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  3. For securing heavy loads the mechanical advantage may be of secondary benefit to the additional friction afforded by the load sharing arrangement. The real tension is achieved by a process called 'swigging', well known to sailors when tightening a sail halyard:-

    Increased tension can be put in the system by pulling outwards in a horizontal direction, taking in the slack, then repeating until taut and tying off. This results in a much tighter rope than simply pulling down to the hitching point.

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  4. http://www.youtube.com/watch?v=TUHgGK-tImY

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