NWslackline guide to longlining (Part 3): WebbingThis video is a fairly short one because there’s far too much to address related to webbing to get it all into one video. Instead, I am going to cover a couple of important and mostly universal topics, and then leave the specifics (tubular, flat, nylon, polyester, etc) to a series of individual webbing review articles and videos where we look at many different types of webbing and their benefits and drawbacks.
Each of these reviews will cover: MATERIAL (nylon, polyester, vectran, dyneema, etc), CONSTRUCTION (flat, tubular, threaded tubular, etc), DURABILITY, STRETCH [at typical longline tension], BREAK STRENGTH, WIDTH (usually 25mm), WEIGHT, and BOUNCE/REBOUND. In general, I’d really like to just speak generally about STRETCH and WEIGHT here.
STRETCH: this is an important one, for a couple of reasons. First because it tells you (more or less) the size of the gap you’re going to have to close to get your line to tension. For instance, if you have a 100M line, and it has 10% stretch at ideal tension, you will need to close a gap of about 10M (actually more like 9M, since your line will initially be 91M and your pulley system 9M, for a total of 100M, but for purposes of round numbers let’s just say 10M). So firstly that means you’ll need a certain amount of rope — if you’re using a 5:1 system, this means you’ll need 4x as much rope as the gap (4x at a minimum; 5x would be more comfortable so you could thread the brake straight off … this will make sense in the next segment). So right there we need 40M of rope. That’s not so bad. But what if your line had 15% stretch at tension? Now we need 60M (just shy of 200ft) of rope. So you can see why stretch is important. For any line with 15% or more stretch, you will need a pretty long rope to get it to tension if the line is more than 100M long. Mostly this series is geared toward lines up to 100M, so it’s not as much of a problem, and also 15% is about the maximum stretch you will encounter in any typical longline material; most of the newer lines that are popular nowadays are in the 5-10% range.
The other reason stretch is significant is that the line will relax everytime you pull some tension. It usually won’t relax back to where it was before the pull, but on average you won’t keep more than half of each pull’s worth of tension (in my experience). If your line is short, say 10 or 20M, it will be very easy to get it to a high tension, because the line only has to stretch a few meters. Even if it’s a “high stretch” line, 15% of 20M is only 3M. This means you will need to pull ~15M of rope through your main pulley system, and with a multiplier that will “feel like” you’re pulling 45M of rope. If you pull about a meter per tug, this is 45 tugs. You can probably do a tug per second, so the line can be tight in roughly a minute. No problem. But, let’s say this is a 100M line, which means everything above gets lengthened by 5. Now instead of feeling like you’re pulling 45M of rope, it will feel like 225M (700+ft!). And it’s really only the last 40% or 50% of tugging that is particularly tough. Well, on the 20M example, that’s only 20 or 30 seconds of difficult pulling. But on the 100M example it’s going to be a LOT more pulling. We can multiply the distance by five to get a rough idea of numbers, but your stamina when pulling hard for 30 seconds is probably not the same as minutes later, so the time it takes to get a longer line tight becomes exponentially more. Did that make sense? Think about it this way: can you do a chin-up? Can you do 2? Can you do 40? Doing 2, for most people, would take a few seconds. Doing 40 would take hours. Because they need rest breaks. Well, tensioning a longline is the same. I am pretty good at pulling nowadays, so I can get a 100M line tight in maybe 15 minutes. A friend and I just rigged a line just over 200M, and instead of 15 minutes it took us closer to three hours of pulling (with rest breaks).
WEIGHT: this is a big factor. Basically you are accustomed to moving the line underneath you when you walk, and on a short line this is no problem, since the weight is negligible. On a long line, with lots more weight and lots more tension, it becomes exponentially harder to move the line underneath you. The lighter your longline, the easier it will be to walk. For this reason, there is almost nothing that feels as good to me as plain old tubular nylon; it isn’t very strong, but it’s very light, and so it feels almost like I am walking on a cloud, compared to some of the heavier lines I normally fight with.
Ultimately, I think having some understanding of the dynamics of weight when walking and stretch when rigging, we can proceed to the next segment and then later talk about specific webbings and which ones might appeal to you based on easy of rigging, cost, durability, break strength, and so on. See you in Part 4! (And if you just absolutely can’t wait for the webbing reviews, I would recommend for most “broke” slackliners to start off with a 150-200ft piece of tubular nylon climbing webbing, assuming you’re in the US where it’s readily available, or maybe a piece of Type-18 up to 300ft in length. If you have a larger budget, buy a 100M piece of both Type-18 and Mantra or ProLine and then decide which you like before moving on to longer and more expensive webbings.)