zipline

bigballer · Jun 25, 2009

i visited a friends place and they had a 60ft single rope tree swing, had to climb up a 40ft ladder attached to a tree and then worm up to a tree stand from there pulled the rope tied to the seat up to the stand, place the seat between the legs and build the courage to lean back and step off.. what F-U-N it was.. now i've got this idea to build a zipline starting in my woods and ending in the lower end of the pasture. a total of 265' and a 20-30ft drop depending on how high i want to make the take off. the upper end will be attached to a large cedar and the lower to a 30" fir. i plan to use 1/4" stainless cable and a petzl or cmi dual wheel trolley. i am no mathmatical expert so am not sure how high the starting point should be in order to get the rider as close to the end as possible of the 265' foot line without braking. i am thinking this will take a few trial runs with some dead weight to get it right. i don't think this will really be a "kids" ride since first of all i don't have any and second of all want to make sure it's an exhilerating ride for my adult friends.. i have done a lot of research and plan to have a harness to start and maybe make a "swing" seat as well.. all legal/liability issues aside, anyone have any input for me or done this yourself? i have already limbed all the branches in the way but there is one old growth cedar stump at least 8ft diameter i may have to move (depending on how high i set the line).

Ridgewalker · Jun 25, 2009

I have ridden zip lines in Jamaica. They have some set ups that are amazing...you will be 150' up and flying for several hundred yards.

One thing to consider...the Jamaican boys have two lines, one above the other and you are tied into both. They used climbing gear and it was very safe. The pix attached is my daughter on the the 1st short run they used to break us in...it gives you an idea of how they did it.

The other think was that they wrapped the landing trees with soft foam...about 2' thick and then they would laugh as you bounced into it when coming in.

ToadHill · Jun 25, 2009

I've thought about making one that crosses my pond for the grandchildren to use, my only fear is they let go too late and hit the bank, still haven't figured that one out.

toivo1037 · Jun 25, 2009

I have been on the Mexican ones too, actually right next the the Jungle where they filmed Predator. 300'+ high and 1200' long was teh biggest of the 16 lines. It was a lot of fun riding the "Mexican Harley".

I also did one at home when I was a kid. About 150' long, and 20' high off of a hill. I used some 3/8" guy wire cable, wrapped it around a tree, and down to the fence pole, and tightened it with a chain come-along. It was high enough that you could clear the UPS truck in the driveway (freaked the guy out) and with the length, it flatted out at the end to slow you down. I actually made a cradle out of 4x4s to get an extra 5' of height at the end. I could kinda control my speed by how much I greesed the pully. I just made a bar out of an old 3/4" pipe, but also had a loop of rope to put your feet in for the girls.

Man, just about everybody rode that thing over that summer.

Ahh the stupid things a 15 yr old will do for entertainment!

Airic · Jun 25, 2009

I had one as a kid that was about 100' long. First it was in our woods and it was a lot fun. Key is to be able to stop before you get to the end. On our first set up we had springs at the end of the line about 10' long thinking it would stop you. Ours was a hang on type. To this day I still laugh at picturing my brother hitting the end and being thrown into back flips into a wire fence 15' away. After that we all made sure you stop yourself on the ground before getting to the end.

A few years later we had built and pond and buried a telephone pole as deep as we could and had the same set up at about 20' before the pole. Worked really well for the first year and then the pole began sag.

I have been wanting to build one for my kids but waiting till they get a bit older.

Attached is a link to buy kits that are not badly priced. I also saw a link somewhere that gives you all your calculations based upon your line type/size and span.

http://ziplinehomekits.com/kits.html?gclid=COW2iczipZsCFRdabQodEA6gCw[/URL]

Post some pics of your progress.

BigEddy · Jun 30, 2009

I have one in my back yard - Just a handle attached to a pulley. Mine runs about 80 feet, starting on a platform about 6' off the ground, sloping slightly down all the way. Once you step off - the highest you are above the ground is about 4'. Kids love it - and no one has ever been hurt letting go.

At the end - rather than a tree - I built a (telephone pole) cross bar about 8' off the ground, about 8' wide and braced it backwards with other poles. That way when the trolley hits the bar - you fly under the crossbar, not into a tree.

Do your calculations on the cable required - to avoid too much droop you need lots of tension on the cable - then when you hang 200lbs or more on it - that tension goes up exponentially due to the angles of the forces involved. 1/4" isn't going to do it. I initially anchored it to the base of an 8" oak - but we pulled it out by the roots over the first season.

That reminds me - add a method to adjust the tension on the cable over time - it will stretch as it warms up. I need to retension mine again - the kids were complaining about the sag last week.

Brahmus · Jun 30, 2009

Ridgewalker said:
I have ridden zip lines in Jamaica. They have some set ups that are amazing...you will be 150' up and flying for several hundred yards.

One thing to consider...the Jamaican boys have two lines, one above the other and you are tied into both. They used climbing gear and it was very safe. The pix attached is my daughter on the the 1st short run they used to break us in...it gives you an idea of how they did it.

The other think was that they wrapped the landing trees with soft foam...about 2' thick and then they would laugh as you bounced into it when coming in.

I've got the exact same picture!! Went there for our Honeymoon 4 years ago this month!

bigballer · Sep 1, 2009

well i finally have had some time to work on this, first had to clear the path which required the removal of one very large old growth cedar stump. i was bummed to have to move my badguy target backstop but that's ok. it's actually mostly intact still so i may just wrestle it into a better location and upright it. suprisingly once i started pushing into it the entire stump moved so it was just a matter of getting on the high side and working under it until i could tip it over. sad to see a landmark like that go but it had to be done.. in the background you can see many other stumps i have dug out since logging the area. they are just drying out so i can light 'em up when the rains return. you might notice a seemingly precarious set up in the last picture but i was actually able to wrap a strap around the tree at the top of the ladder to stabilize it, that right hand reaching branch was out over the lane far enough to worry about so i figured better to cut it now then to have it fall on the cable this winter in a heavy wind storm.

mjncad · Sep 1, 2009

The first picture of the stump and target on it reminds me of a mini-version of Devil's Tower in Wyoming as seen in 'Close Encounters of the Third Kind.'

bigballer · Sep 2, 2009

some supplies to get this started:

1 Petzl P24 Trolley with built in carbiner as backup incase of bearing failure, good for 35MPH and 650Lb working load:

300ft of 3/8" 7x19 galvanized wire rope
3/8" drop forged clips
3/8" thimbles for loops:

I made 2 10ft slings to wrap the tree each ending with a thimble for attachment to the turnbuckle, added blocks with a routed groove put in place to protect the tree:

Ideally one would have a gravity stop but I decided to add this block in order to slow the rider to a stop, 2x25ft of 1/2" shockcord secured to side tree makes the stop smooth and effective depending on the weight of the rider it will shoot you back up uphill for an easy exit: