As weird and ambiguous as this might sound, I’m attempting to suspend 5mm (3ply) jute twine horizontally across a short distance of trees, much like a clothesline but for decorative purposes (specifically for an experimental video). Regardless of how strangely I’m leading into this (and hopefully without having to further explain the larger context behind it), I need the twine to be tight enough so it’s straight, which is easy enough to to begin with, but it keeps losing tension after a few minutes no matter how tight I make it.
I have 5/32" diamond braid polypropylene rope tied off on both ends of the twine, which are then tied through i-hooks (drilled into sturdy trees) and tightened off with a trucker’s hitch. Essentially the twine is tightened in the middle of the ropes because it’s simply a lot easier to tie a trucker’s hitch with something that has far less friction. But again, after a few minutes, it begins to slack.
I found out that polypropylene has a good amount of stretch to it, which is most likely partial as to why it keeps loosening so fast, but I haven’t found any resources that suggest the jute twine could also be stretching out. Originally I was planning on just replacing my polypropylene with polyester cord, yet if it’s the case that my twine is stretching out too much under tension, then it propbably wouldn’t make much of a difference.
All that to say, is it most likely that my twine has too much elongation in it and should be disregarded for this type of task?
My twine: https://www.amazon.com/gp/product/B08TWNTZDP/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&th=1
Perhapsananswerforthequestion,
What you are experiencing is called creep. It is something that is quite typical in natural fiber ropes. Even synthetic ropes will experience creep, however, of you spend big bucks, you can purchase something like Dynema that has very low creep.
One solution to keep tension on a line is to install a pulley at one tree, and suspend a weight to keep your line taught. You will be able to track creep as the weight moves lower. Humidity will also have an effect.
Pat