speed line technique

Right on! So first off lets determine the difference between a zip line and a speedline. A zip line has no control on the piece of wood or tree being removed. A speedline is set up with some sort of control line on the piece being sent down the line.

I would recommend DMM Revolver carabiners or small pulleys for attaching to your speed line. Carabiners work fine but I find that the added friction makes it more difficult to get pieces moving quickly.

Webbing loops are great slings. Buying 1" tubular webbing in bulk is a great way to save money. Use something like a Beer Knot to make an endless loop. Girth hitch this to a biner and then girth hitch that to the limb you want to zing down the rope.

I tend to like a method I call "freeballing" the zip line. This is when the ground anchor is not a stationary object rather it is a ground guy holding the rope. This method is quick for lighter pieces but if the piece were too large could cause the ground guy to get dragged across the ground, the piece to drop and damage anything underneath, or for the grounds man to be dragged into the uncontrolled piece. Use at your own risk.

Usually the ground anchor is secured with a port-a-wrap or with a 3:1 then to a port-a-wrap. This helps to tension the line and to reduce the drop in the line. One thing to keep in mind is vectors on your rope when speedlining or ziplining. Vectors are the direction of force, in this case, on a rope. The more tension placed on the anchors, in tree and at the ground, the higher your vector force will register along the rope. As a piece of wood is loaded and sliding along the speedline it creates forces far greater than those associated with normal pulling of a rope.

This is illustrated very well with a simple example. After you are done climbing and have descended out of the tree walk until you are at the end of your climb line. I'm assuming you will have quite a bit of rope and a very good rope angle from your tie in point. Now, lean backwards into your harness and your rope until you are almost laying down. Have your grounds person pull on your rope trying to pick you up. More than likely you won't move very far. Now have your grounds person reach up as high as they can on your rope and pull directly down. Even the lightest of workers should be able to easily pick up the heaviest of climbers. This is possible because of vectors and multiplied force. The downward pull on the rope creates huge amounts of force with barely any effort.

This plays into the fact that your speedline could be anchored into the removal tree or adjacent tree. Be sure that if the pieces to be removed are large that the anchor is large as well along with the entirety of the trees structure.

Aside from all the math and physics, speedlining is badass and can take a ton of work out of your job. Send pieces down a rope directly to the chipper. Awesome!

Here is a ziplining video from a couple years ago that I made. Pretty sure its my first GoPro video.
 
Not much more that can be said. That was a great response above! I personally didn't know there was a difference between a speedline and zipline but I like the differentiation between the names. I've always called the slow one a "controlled speedline". I would certainly try the example he mentioned that demonstrated the vector on the line. It's a good thing to understand in our world.

Maybe I can mention a couple more things: :)

1) Watch Jake's video above. Notice how much faster and harder the logs come down compared to brush. Like he said, logs usually need a good anchor when ziplining so be very careful to release that tension as early as you can, because they WILL bounce and come at you, or at your anchor point very hard. Get out of their way and watch for targets. Be careful with logs on a speedline because they will surprise you. And don't even try to speedline a log as big as you can lower with a rigging line. Big difference. Start small and learn as you go.

2) Rope - the best ropes for a zipline or speedline have very little stretch. This is not always super important but in the game of inches it will be. If you're trying to miss a target below you don't want to play the stretch game. And you need to have a kernmantle rope in the truck for that purpose. Preferably a long one. For the majority of speedlining we do that's not a big deal but you don't want to figure out that you need one when you're on the job.
 
sounds obvious but, lacking a mentor, i figured this out the hard way. consider the length of your sling and where rope is which you will be sliding it down. if your pulling the rope out of the straight line it wants to be in, consider the distance of which your moved it. your going to have some sag in the line once the piece comes off.

i have lengths of rope from old tag lines that i use when i need long slings so i can keep the speedline rope in its straight line. just gotta make sure it'll hang high enough
 
I remember quite a bit of discussion about speed line force multipliers in threads from years ago.. There is a chart somewhere too. The force multiplier depends on the angle of the line when loaded... I prefer to have enough play in a zipline to make sure those forces never get too high. I think the force multiplier comes down to 1:1 at about 18º. You get that by either using a line with a good bit of stretch, or leaving a some slack in a static line. that is going to result in a lot less vertical clearance,... If you don't have that 18º in the line, then you need to be extremely careful about shock loading the system, as you could be side-loading the tree with tremendous forces= a good chance of killing yourself. Any questions about the stability of the tree you're in, then back it up with guy line.

You can get around the vertical clearance issue a few ways... I've tip tied and but tied big limbs so the piece stays horizontal. Or you can start with a real high anchor point... I rarely use a ziplines.. Just doesn;t make much sense for most of my jobs, given the topography and access to yards.. The west coast guys that work on hills a lot, are the experts.... there were threads from the mid 2000s that got into a lot of detail if you can find them.
 
There is lots written about forces on a speedline. Too much to rehash in my post

Take some time and have a good understanding of the load multiplier issue. If you find a chart showing the loads on carne rigging slings you can flip that upside down to make to look like a speedline. More sag will reduce the anchor loads. More rope in the system will too

While your learning start off using really small limbs and huge,solid anchors. Watch how the anchor points reacte to various loads
 
In our language, 'speed-line' is for tree work & 'zip-line' is for people.

In treework we have two types of speed-lining, controlled and non-controlled.

With tree work, being able to tension the speed line can be crucial.
 
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