Mini Skyline for firewood...

[SkogenMe]

I realize this doesn't fit the cheap category but there is a bunch of useful info:
http://www.forestry.gov.uk/pdf/td_cableway_extraction.pdf/$FILE/td_cableway_extraction.pdf

I came across it when I was trying to find references to a tractor mounted skyline rig that I had seen in operation in Europe many years ago (made by Igland).

 

[JimS]

Thanks for the good info, links and such.

Shinnlinger, on the library books... Sounds very interesting but there are lots of similar books. Any chance you could supply exact title, author and/or ISBN? I did some searching but didn't find it. I also found references to some publications by the Forest Service that looked good but they aren't available on line.

I had considered a 4 wheel cart and cable to pull it up the hills but with very rough ground and brush that didn't seem practical. I also considered a winch line with possible block slightly elevated in a tree at the top of the hill to get a bit of lift to reduce digging into the dirt and allow the tractor to pull on the upper, flat ground. Long heavy cables and lots of tearing up the hillsides and small trees were big negatives.

As noted the tension in the cable is many times the weight of the load. That's why I thought I would limit the load to around 200 lbs. Also the tighter the line is the more tension for a given load. Ignoring the weight of the cable and considering the cable to be straight lines from the carriage to the end supports the tension can be approximated as:

T = load x sin(theta) / 2

Where theta is angle between horizon and cable.

Theta Tension
2.5 degrees 2293 lbs
5 1147
10 576
90 100 (extreme case with vertical support lines)

For small angles the load doubles for half the angle as might be expected. For 1/4" cable the working load is 1400 lbs so I considered 5 degrees the minimum angle.
For this angle the sag in the cable is:

Sag = sin(theta) x length / 2

for 250 ft length the sag is 10.9 ft

This is quite a lot of sag but given the terain this should be workable.

More tension reduces the sag but greatly increases tension: 1 degree gives 2.2 ft of sag and 5730 lbs tension.

Again these are approximations. And this is for the worst case of a horizontal line (both end supports at the same elevation). For sloped lines the main line supports less of the load and the moving carriage line supports more of the load.

 

[pat32rf]

While your system would be fun to build and operate I find that its a lot quicker to just haul them up. If you use a "nose-cone" or just make sure that the cable is hooked to the bottom side of the log it won't really tear up the terrain if you watch your pulls, as opposed to just trying to muscle them up with the tractor.
200 ft of rope is a long run to buy and handle but with the skyline you will be dealing with at least twice that amount of cable plus the drag rope.
If you have another body to drive the tractor then I'd also invest in a set of radios, preferably with a "hands free" feature.
My land is also mostly up and down and I limit my pulls to 100' or so. Since I work alone I use a $400 4ton electric winch on the back of the tractor with a wireless controller. I drag the cable down the hill, hook up, then return to the winch to engage the clutch, climb back down to where I can see the log and hit the remote for the winch. If the log hangs up I release tension and fasten a small (light) snatch block to a tree to guide the cable and log around the hang-up.
I skidded out about 6 bush cords last year, mostly dead oak and other hardwood in the 4-12" diameter range, seldom having to cut to length until it was up at a landing where I loaded unto a trailer/log hauler that I've built.

 

[Treemonkey1000]

Ok just a couple of quick thoughts. How steep are the hills? Can you get a horse or mule team in there? That's one idea. Next is can you get a clear path to your landing? If you can clear enough of a path so that you can skid them with the horse team. Or clear a path for skidding with a drag method. If you watch Axe men on TV at all they anchor their skyline to a tree stump. Then they are yarding trees up with 10,000 lbs of trees with a skyline. Granted their tower has a strong winch to pull them up the hill. What I was thinking was string your cable from a tree at the top. Put some guy wires at that tree on the back side to support it. Then use a block and tackle to lift the log a little or taper the front of the log so as to not jam into the dirt as much. You can use a chainsaw winch or something to block and tackle your logs up the hill to your landing. For example a set of pulleys and your rope will give you a fair amount of pull. I have used a climbing rope and 3 pulleys to pull tree's that were leaning the wrong way backwards. (Mechanical advantage to my 150 lbs soaking wet) You math geeks could work it out. Put a winch with 800-1000 lbs of pull on a 3/1 or 4/1 pulley system. Drag the log up the hill in stages. Depending on how long your rope is would determine how long your stage is to pull. Primary thing is to be safe and ready to bail out of the way if something breaks.

 

[JimS]

Pat32rf, I like the idea of radio control. Can you give us more detail? Was it a radio control winch to start with or did you combine the winch and radio control? I will probably end up getting someone to help so one person can load and the other run the winch and unload.

The skyline will not be "live" just anchored on each end so the length isn't doubled. I figure 250 ft will do nicely but it is still a long cable and I need a rope or smaller cable the same length. I don't plan any haulback line - gravity should take care of that. Most of the runs will be around 30 degrees overall. The hills are over 45 degrees is many places (even a few 50 ft vertical spots).

Found a few things the forest service has put out of interest...

One of their locations put out plans for the "Bitterroot Mini Yarder". It is much bigger than I planned and goes on at least a 3/4 ton pickup or trailer. Still interesting.

Another is "Feasibility of Collecting Firewood Blocks with a Small Skyline." In it they were sending the wood down the cable. They just used J hooks driven into the blocks and a wedge arrangement to pull the staples the bottom. They used #9 wire and 1/8" cable but had a bit shorter spans and lower weights. Similar...I just need go a bit heavier and use a winch to pull the wood up the cable.

I figure I can do this for around $250 by the time I get cable, pulleys, tree straps, etc and use a few things I already have.

 

[charlz]

One of their locations put out plans for the "Bitterroot Mini Yarder". It is much bigger than I planned and goes on at least a 3/4 ton pickup or trailer. Still interesting.

That's funny because that is the part of Montana I grew up in. I've seen people with setups like that on the back of old military trucks etc. Small 'post and pole' operations mostly. Since the enviro-nuts have killed off almost all logging and tree harvesting I'd bet you can find them sitting in the weeds all over western Montana.

 

[shinnlinger]

HI,

Sorry for the delay, The book that sums up homeowner skylines and even a capstan system off a truck is The Harrowsmith country guide to wood heat A good book to practically solve these kinds of problems.