Feel the Tension!

I know a couple of knots. I'm a climber, so I know my figure-eights and my clove hitch. I learned girth hitches with rubber bands as a kid, even if I didn't know the name at the time. But that's about it. Knots are really interesting things, but I can't say I ever remember them when I need them.

Like, for example, when I'm trying to string up a rudimentary washing line.


I mention that because I did that every day for a while while hiking just recently. Just a line between two trees. The problem isn't in making the line stay up, it's with getting a bit of tension in it. There's actually a "tautline hitch" that's probably good for this kind of thing, but can I ever remember how to tie that when I need it?...

Then again, maybe that's just my excuse for making a 3D-printed thing to do the job instead! I was familiar with the classic two-holes-through-a-bit-of-plastic style adjuster, and that's kind of where I started out in designing. Those are awkward for putting around a tree, though. As the pic below shows, I went through a few design changes before I got to a point where I was happy.


The final version has the following features:

• A t-shape and loop for locking the tensioner to a point on the line. This can even be the end of the piece of line, if you're using this to join two pieces together and tension them (or to form a loop).
• A pulley that lets you tension the line easily.
• A second pulley that reduces the force needed to hold the tension in place
• A grabby toothed bit to hold the end of the line.

I used this thing nearly every night for about three weeks and it's been great! No slippage, nothing comes undone, and I haven't broken one so far, either. The print orientation gives it a fair bit of strength.

I've been using this with 5mm cord, but it should scale pretty well. Softer lines will of course be easier to work with than harder ones, but that goes for regular knots as well...

Maybe one day I'll spend the time to learn more knots properly, but until then, I'll be using these :)

For some instructions on use, check out the pics in the Dropbox folder. Or, probably more usefully, take a look at the short demo video I'll be posting on Instagram very soon! 😁

Enjoy!