Lighten Up Guys

I am going to be installing a cable zip line (tyrolean traverse) between two trees about 500-600 feet apart. I will be putting platforms on either end, setting it up so you can ascend a fixed rope to the launching platform, zip across, and rappel from the landing platform. The zip line will be clearing a goat barn and some short oak trees, and will probably be 30-50 off the ground. Here's my problem- neither anchor tree has sturdy branches for at least 50 feet. The top tree is a large fir, maybe 90-110 feet tall, the lower is a huge ponderosa pine, I have no idea how tall. Originally, I was going to use boot spikes and a rope around the back to climb up the first time and anchor my rope, but I'm worried about damaging the tree. Do climbing spikes damage a tree significantly? It would only be a one-time climb for each tree, to fix the ropes, I just wondered whether the holes would let in pests, cause decay, or something like that. The trees are pretty valuable to the owners, so I wanted to make sure. In the past I've used a bow (and one time a bottle rocket ) to shoot the line over branches, but not at this height, or with branches as small. The spikes just seem easier, and safer, but I don't want to hurt the trees. Any ideas?

Any wound inflicted to a tree that goes beyond the cambium layer can hurt the tree. But being that it is winter most pests are dormant and will not get to the tree right now. Either way I would never use spikes on a tre that is perfectly healthy and isn't to be removed.
I would recommend using a large extension ladder if you cannot get a throw ball were you need to be and use a pole saw or some sort of long pole to place your rope into the tree and just keep advancing your line until you are at your desired location.

Grants Pass? You're close to New Tribe I think, you might be able to get a reference from them for someone who would be very happy to guide you in climbing up safely and spikeless. No harm in asking.
-moss

New Tribe

Yes, any technique that breaches the bark down to the cambium layer has the potential to give entrance to unfriendly fungi, bacteria, or insects. It's true that these guys are inactive in the winter but, unfortunately, the tree's wound healing machinery is inactive at that time too.

There is a very slow, laborious technique known as girth hitch climbing that can get you up a limbless trunk. It involves 2-3 webbing slings girth-hitched around the trunk and alternately standing on one while shifting the other up, then hanging from the other sling while shifting the first one up. I've never done it more than 10 feet or so - but Joe Maher and a few others have worked with it some - best to get their take on it. For up to 20 feet or so, I've used a few tree steps like you can buy for getting into a deer stand (the kind you strap around the trunk, NOT the cheap kind that screw into the wood) in conjunction with a lanyard around the tree trunk. I'd be a bit jittery about using that for anything much higher than 20 feet though.

50 feet up to the lowest branch is definitely not very high to reach with some practice and a regular 10 oz throw bag and regular thow line. We reached higher branches than that in the Oregon Rendezvous with a small cross bow (pistol type) and a small tipless arrow that you can get from New Tribe in Grant Pass. Tengu at New Tribe can help you with some direcction on setting your initial line. I hope that you have experience setting Zip lines since they are rather dangerous in the hands of inexperienced users. There is a good web site from a company that sells all the gear for the zipline and has a basic set of intructions and disclaimers for the low to the ground lines. (Do a Google search ). The one I saw being operated in South Oregon was probably 600 ft long and maybe 10 feet from the ground.It was definitelly a rush. Good luck.

Hey, thanks for all the intput! I think I'll go ahead and try a throw line for now. I can cut the distance down to around 30' with an 20' extension ladder, so it shouldn't be too hard. I can only work on this during the weekends, so I'll be trying it out Saturday (if it stops raining!).

I am familiar with New Tribe, and the Out-n-About Treesort. New Tribe is probably less than 15 minutes from where I live. I'll definitely give them a call if I can't get this figured out.

Probably think we're a bunch of worrywarts
Ladders against trees are exceptionally dangerous, even a 20 footer. Shoot, I've seen a guy flip a ladder leaning against the side of a house and he was a very experienced painter. He ended up hanging by his arms since the ladder caught a porch roof as it was sliding down across the front of the house. A tree gives no such buffer. Soft ground and rounded trunk makes a ladder less than optimal. If you ever look at a photo of an orchard or pruning ladder you'll see they are extremely wide at the bottom and taper to the top

Good luck whichever method you end up using. Post photos when you're done!
-moss

That's pretty easy to take care of- by tying the ladder down to the tree. You can then clip onto the ladder and lean back, if need be. I've never used a throw bag before, but I'll get something figured out. I'll be sure to post photos when it's done!

If anyone wants to check out my website, it's Sleaddventures.com
I've still got a ton of work to do on it, but it gives an idea of what my business is like. I'm putting up this zipline so I can take photos, make diagrams, etc., for an instruction manual that would go with my zipline kits.
Thanks again for all the advice!

-Nate

Nate,
I have some insurance I'd like to sell you...

Seriously man, ladders are a bad deal, especially what you're talking about doing with it. You can secure the ladder, you can secure yourself to the ladder, but what happens when you loose your footing (because using a throwbag does actually take some coordination)? I'll tell you what. You'll drop a few feet to the end of your lanyard, which HURTS (I know), then you'll dangle out of reach of the ladder, unable to rescue yourself. Soon you'll get compartmentalization, and the toxins will build up in your blood. By the time you do get rescued, which WILL be a dangerous operation, IF you've retained conciousness make sure they don't lay you flat, because all those toxins are gonna dump into your system, and stop your heart.

Seriously, call Tengu, call the folks at New Tribe, somebody'll be glad to come out and set some lines for you.

It's better than the alternative.

Climb Safe!
Leave the ladders in the garage.
Icabod

I would imagine selling zip-line gear a close runner to selling fireworks. Make sure you have lots of insurance for the person who sets it up improperly or if you have any gear malfunction. Zip lines is not nearly as controlled as roped tree climbing.

Everyone has the right to make its own mistakes to learn a new business... so do not discourage the guy from giving it try. If it works... and nobody gets killed or seriously injured then he makes some money. If someone gets killed, looses a limb, is permanently disfigured and loses a limb them he gets some time to think about insurance lawsuits and safety while figuring out how to pay for the damages.
So, lighten up and let the poor guy do his zipline stuff! There are companies that actually sell this stuff . Here is a link to one
http://www.bonsai-design.com/zipline.htm

hehehehe.

Hey, thanks for all the input.
I got a line up with no problems, and have finished the launching platform. It'll probably take me a couple more Saturdays to get everything up. I'll keep you posted.

Nate,

Can you share your design process with us? I'm always curious how people calculate what materials to use when they build ziplines.

Are you using rope or cable for the line? How are you attaching the anchors to the trees? How do you determine the angle of the line? How do you determine the line tension?

Tom,

I'd be happy to. I use steel stranded aircraft cable (galvinized, 7X19 construction), anywhere from 3/16" to 3/8" in diameter. A majority of what I sell are short 100'-150' lines, called Mammoth Zip Lines, with a handle bar and a harness for safety. These are much like the 'Fun Ride' kits you would see at a Toys-R-Us, with the addition of a harness. The rider never goes more than 5-10 feet off the ground, and coasts down the cable until they come to the ground. The kits come with a lead rope as well, so an adult can guide smaller kids down, as they just sit in the harness. The kits can be used many different ways, some customers use them to get down from treehouses, some string them over swimming holes; they're really versatile.

The kit I'm working on now (called the Mammoth Deluxe) is designed for longer distances, and for rigging higher off the ground. The rider can reach the launching platform by ascending a fixed rope, a climbing wall, rope ladder, stairs, whatever, zip across, and then rappel from the end or clip onto the next zipline. The cable is anchored to the trees by wrapping a heavy duty nylon sling aroung the tree, and clipping the thimbled cable to the eyes. In addition, a safety cable is wrapped around and clipped to the line, in case the nylon strap fails. Tension is kept off the safety cable to protect the tree.

As far as slope- I usually recommend a 5%-10% drop from start to finish. It's really quite flexible. As long as the rider has the ability to control their speed with a braking device, the only issue is to make sure it's steep enough to reach the end.

Line tension is also flexible. A very tight line will start out slower, and continue to pick up speed til the end. A loose line will start out very fast, the rider
dropping quickly, but will slow down at the end as they pass the low point of the cable and start going uphill. I use turnbuckles or heavy duty ratchet tie-down straps for tightening the cable.

Braking devices- right now, the best thing I can find has been regular work gloves, with an extra padding of leather stitched into the palm. The rider simply applies friction to the cable behind the trolley to slow down. I'm also working with a machine shop in the Portland area to come up with a braking device that can be inserted into the Petzl Tandem trolleys.
I sell the Petzl Tandem Speed, Tandem Cable, and Trac pulleys for the longer kits, and make my own trolleys for the short 3/16" cable kits.

After many a Saturday afternoon, the zip line is finally up and running. Here are some photos, as promised.

Ascending to the launching platform (you call this SRT, correct?)



View of top platform.



Going for the ride.



Bottom Platform.