The Basics of Using a Throw Line and Weight

Posted by Professional Tree Climber on 7/23/2020 to Tree Climbing Gear
The Basics of Using a Throw Line and Weight
As I’ve stated many times over, the throw line is one of those tools that is often overlooked but can make your day far easier than without. As with everything, practice really does make perfect when it comes to this mega useful tool. Let’s discuss what throw line is, how to throw it and what some of the best uses for throw line are!

So right off the bat, throw line is a small diameter line most often produced of HMPE (high-modulus polyethylene) or Dyneema. Both of these fibers have a waxy feel that allows them to easily slide over limbs once in the canopy. Because of the amazing synthetic fibers they are made of they also retain enormous amounts of strength in relation to their size. A very common length of throw line is 180’ and the most common diameter sizes are 1.8mm -2.2mm. This small diameter line is attached to a throw weight or throw bag bag with a slippery eight hitch, clove hitch, or even a spliced eye. Most times the throw line is stored in a throw line cube which is a wonderful piece of origami art work that forms a standing cube when unfolded and folds down into a small triangular storage unit when collapsed. The throw line is flaked into the throw line cube. Flaking is the process of feeding throw line or rope into a bag or cube on top of itself. As each layer of line lays on top of the former, it allows the line to be pulled from the cube without tangling because of the layering system. This is far easier and far more efficient than some of the older more archaic ways of throw line storage such as wrapping the 180’ of line around a stick or putting it in a 2 liter bottle!

The point of the throw line is to allow the climber to remotely set their climb line or rigging line into the tree in an ideal tie in point (TIP) or rigging point. The throw line is attached to the throw bag which is then thrown into the tree, through a suitable crotch or union and lowered down to the ground. Once the throw line is back on the ground, your climb line is then attached to the throw line and pulled back up into the tree, through the crotch and back down to the climber. The throw line can also be used to set rigging lines, floating rigging points, friction savers or more advanced options like the ART Twin Line. Being able to set your climbing line in the tree reduces a ton of extra climbing as well as effort and time. This is a major game changer when it comes to being able to work a tree from the ground up because it allows you to have a great rope angle from the ground up instead of having to rely on a TIP that is only a couple feet above you as it would be if you were climbing the tree ground up with an alternating lanyard technique or something along those lines.

There are 3 common ways to throw a throw line into the tree. The first and probably most common is the Granny Throw or the basket throw. This throw is performed by putting a bight of throw line through the ring on the throw bag and hooking it around your index finger on one hand. The other end of the throw line that exits the ring opposite the bight you just grabbed is then held with the opposite hand. This allows the throw bag to be held by a basket of throw line. The bag is then swung back and forth in a pendulum between your legs. The swing of the throw bag should line up with the target you are aiming for, When you are ready to shoot for your target, the grip is released around both lines and the bag will shoot through the air and “hopefully” go through your ideal TIP!

The next technique for throwing is set up exactly the same way as the basket throw except the throw line is all held in your dominant hand instead of separating it between both of your hands. This is called a single hand throw. The bight of throw line as well as the working portion of the throw line are all hooked over your index finger. The bag is then swung in a pendulum but on the outside of your dominant leg. This is my preferred method of throwing because it allows me the maximum height as well as the accuracy that I am looking for.

The third technique is called the trigger shot. The process of throwing is very similar to the single hand throw but the set up is a bit different. The throw bag is laid on the ground and the throw line is grasped just above your knee. At this point a slip knot is tied in the throw line to create a small bump or trigger to grasp. The throw line is then swung in a pendulum fashion again and as the throw line is released, the slip knot pops out and the bag again, hopefully, goes right through the ideal tie in point!

One of the biggest tips I have for climbers learning about throw line is to never let the throw line go once you’ve thrown it. After you release the throw line on your throw, let the line pass through your dominant hand. Too many times climbers will throw the line and just drop it to the ground as it zings it’s way through the canopy. There are way too many times that the throw bag passes through the TIP and it can easily be stopped which reduces the chance of it getting tangled in the many sticky limbs that it would have passed over if you didn’t stop it in time. This is also a great thing to keep in mind when throwing in tight quarters to reduce the chance of a strange bounce that could end in a dented car hood, broken lawn ornament or broken window. Don’t let go of the throw line!

All of these techniques work great and some work better than others in certain situations. Personally I feel very comfortable throwing single handed up to heights of about 80’. This is my go to technique for big throws as well as straight up throws. When it comes to smaller trees with tight canopies, I might use the basket throw because I can throw it short distances with pretty good accuracy. I used to throw with the trigger shot for quite a few years but found I couldn’t get the throw as high as I was hoping for. After switching to the single hand throw there was a noticeable change in the height and accuracy of my throws.


Abdon at Bartlett has put together a great video illustrating these techniques if you are looking for a bit more clarity outside of this written word. We will have a second blog post explaining some of the more advanced techniques that throw line can be used for outside of just setting climbing and rigging lines. There are some techniques that we have covered in the past that will be revisited to keep all the throw line resources in one general area. Again, I can’t stress enough how useful a throw line can be to your work process and flow once you’ve become fluent with the techniques, nuances and sometimes, the struggle of throw line! 

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