How to Weblock – Insights into developing gear

Mhm. This is not a promotional article. Well, not entirely at least. I want to share the story of how a new piece of equipment came to life.

How it all started:

My slacklining life started in 2012 on a very, very long retired industrial round sling which I found in our garage. It was already terribly worn out at one point, so I decided to cut it right there and ZIP my first slackline was born. 12m long minus whatever length it took to tie it around the trees. Without tensioning system, without guidance, without any idea on what exactly I was doing I was having an absolutely fantastic time. Every time I returned from the woods, getting better and better at the actual slacklining, I started scavenging for new equipment in our garage. Not long and I discovered that cargo straps were easier to walk than industrial round slings. However, it took another month or so until I could solve the issue of attaching webbing to a tree in any sensible way. A shackle and a steel pipe seemed to work best for me. I always 1.5 wrapped it, though I had no clue that there was a single wrap method. After semi-rodeoing for a while it was time to ask the omniscient internet for help..

Probably one of the biggest revelations I ever experienced. A world full of slacklines. And I never ever met or even heard of one. Fast forward a little and I am buying my first longline equipment. CAMP bushing pulleys, a static rope and 100m of blue Type-18. My linelockers improved as well:


Fast forward again and I help myself to 304.5m of green Type-18, SMCs, the MPD and AWLs. Proper weblocks for the first time, I totally fell in love. But I wasn’t entirely convinced, so I started designing my own. And this is where we begin:


The Q. A weblock which can be wrapped in any configuration you want. 0.5 wrap. 1.5 wrap. 2.125 wrap. Whatever the webbing, you can get the right amount of friction. „Lightweight“ due to the massive hole in the middle. Along came the RamLock and my idea looked like shit. Back to the drawing board!


Theses ammonites are fucking ugly, but promised to pretensionability for dyneema webbing. After taking my first steps on dyneema webbing, I decided to scrap this abomination. Who would want to walk dyneema? What is wrong with you?


A modification of the spiral model followed soon enough. The Blob-Lock. I wasn’t too unhappy with it, although the diverter presented itself to be difficult to manufacture at home, so I went looking for an even simpler solution.


Here we go. The Fishlock was born. And soon enough this draft became a reality in February 2014. Up until now, I never thought whether any of these inventions were particularly useful for anyone else besides me. The weblock was really really small. It weighs under 200g and looks, politely put, a little fragile. I tested it up to 12kN and nothing seemed to bend. I was content with that and used it in lines up to 5kN of tension. The sideplates were laser-cut from stainless steel and the diverter was made from an industrial plastic and shaped with a drill, a saw, a file, heaps of sandpaper and even more patience. I took it to my first slackline festival in Switzerland only to encounter the Zilla 3.0. What a ridiculously big thing. And how much nicer it looked than my handcrafted skipping stone. Nevertheless, the Fishlock was cut out to fill the gap between the low-budget low-end solutions that EQB was providing and the more financially demanding solutions presented by LC or BC.


And so I started to work with Michael from to develop an affordable weblock solution. Project Fishlock was getting serious.

The design process:

Since other people were (hopefully) going to use my weblock, it was time to think about safety. Until now, I was able to put restrictions on when and how to use the Fishlock, but that would not be the case, once I was no longer the only one using it. This meant making it idiot-proof.

The first design lacked strength. Obviously. So the second generation would be a lot bigger and tougher. The plastic diverter was thrown out and replaced by aluminium. The bolts were changed for higher grade steel ones. Edges were rounded and the anchor hole increased in size for greater connection versatility. A lot of numbers were juggled. In the end it turned out they quite accurately represented the results of the break tests, but that could have been sheer luck, since I don’t have any engineering education. And thus the Fishlock was reborn:


I used them quite thoroughly for a few months and they worked outstandingly well. Some (unique?) features I introduced were a linear spiral form for better pretensioning. The reasoning was that webbing will ‚fall‘ into a logarithmic spiral shape by itself (try air-wrapping your webbing around an imaginary weblock and look at the shape the webbing produces) and forcing it around a logarithmic spiral or anything with lower curvature (like a normal circle) will create drag on the diverter, whereas anything with higher curvature (like a linear spiral) will result in the webbing lifting itself of the diverter and running freely around it. This explanation might not be very clever, but the effect is very real. No other weblock pretensions as well as the 2nd generation Fishlock.

However, there were still some issues with the device. For one, it wouldn’t fit all webbings easily. T-Wave for example just barely made it. And using double webbing would not work with most webbings. The position of the 2 bolts in relation to the diverter would result in a torquing moment that was greater than necessary. The solution? Just move the lower bolt further down. In comparison to the first iteration, the second one was really big. It weighed 330g. After testing it for efficiency, it became apparent that it was too big.


The webbing broke outside the weblock. It was needlessly efficient.. Back to the drawing board again!


The final version weighs in at just 225g and is thereby the lightest conventional weblock currently available. The pretensioning is great, efficiency shouldn’t be terrible either. Break test results will come back next week. It accomodates all webbings and most of them doubled up. And now it finally looks reasonably nice as well.



All in all, it took more than 12 months of work to get so far. Countless changes and discussions, endless sessions to see how it worked and whether it was reliable. One of those ended in 2 world records for length on polyester and polyamide, which I am very happy about.

Now. I don’t want this article to end without any sort of meaningful message/purpose. I would like to start a collection of what is out there, present it to the world and share the stories of self-made gear and equipment, so that we can learn from and help each other in continuing to develop this life of ours.


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