ground skiding

[Gabe Ayers]

Carl,

One question/thought comes to mind about the ground skidding versus the use of an arch.

When the horse is properly fitted with a d-ring harness the point of draft is kept stable by the belly band, despite the attachment point of the tugs according to Les Barden and our experience. So I wonder how you see that a horse can pull more efficiently when ground skidding instead of using an arch with d-ring harness.

We think of our arch as being a rolling lever. The frame is cantilevered forward and keeps the load lifted as the device is moved forward. This provides tremendous advantage to the animal in applying itself against the resistance of the load, by simply putting much of the weight on the wheels of the arch. The higher point of draft with the double tree being on the top of the platform essentially keeps the rolling lever lifting the object attached to the slot bar by pulling it forward over the arch created by the cantilever.

When it comes to giving all they have, our horses make the same all out effort whenever asked properly and I am not sure how there could be any advantage to ground skidding as it relates to the animals efficiency of using itself. I understand the draft or lift provided by the animals movement forward and the line of draft, but that seems to be less of a concern when using D-Ring despite the high point of draft on the Fisher style arch.

Help me/us understand what you mean sir.

I actually enjoyed the research work by Tim Harrington and associates about measuring resistance using certain devices and situations. Such studies are good for our culture in that they at least formalize many discussions among teamsters. Unlike most research, at least it didn’t end with a statement about requiring more research.

This question/thinking doesn’t suggest or imply that I am against ground skidding, we do it all the time. There are definitely settings that allow wood to be moved quicker and more efficiently using a single horse and ground skidding. We move most of our smaller sized firewood this way and often use a single to set logs out of tight places to the skid trail and the team on the arch to forward out to the landing. It is the bunching and forwarding system approach and the single horse is so quick and good at such movement of wood particularly in tight places. One of the best things about single horse logging on the ground is that there is essentially no skid trail swamping required.

Sincerely,

[Carl Russell]

The wheeled arch does provide advantage by creating a fulcrum over the wheels to lift the load, which reduces friction and makes the load move easier when pushed. And as Scott describes, the “line of draft” is still from the shoulder to the log, but the line that the horse can push on is not the low one, but the higher one.

The “efficiency” that I am referring to has to do with the horse lifting from it heels to it’s shoulders. Although with the D-ring that angle of draft is maintained on the front trace, it is redirected across the rear trace, so that the horse looses its ability to actually get “under” the load, so it turns its power into forward pushing instead of forward lifting.

Because the arch is holding some of the weight this may make the work less arduous on the horse, and in fact it must be, because the horse cannot apply all of its natural power, not being able to lift as well.

Jason, I wonder if you have ever tried to move a loaded stone boat with an arch. My premise is that although the horses may “try” as hard as they usually do, they won’t be able to get their front feet off the ground and “lift” they way they usually do.

Now this is not speaking to large diameter logs that roll with the chain on top. This is where the arch really shines, because you already have a high draft, and then the fulcrum works to the horses advantage.

But this also points out the perfect example of what I am talking about. Let the log roll so the chain is on top (ground skidding), and see how the high draft affects the horses ability to move the log. Find some way to get the point of draft back to the ground and you will find that the horse can apply its power more efficiently. They will also have more confidence, which is the part that can’t be measured in foot/pounds.

The other part of the arch is the reduced friction on the dragging log. Ground skidding, you don’t get that advantage. But use a Go-devil or a Bob-sled, at which point you are back within the horses comfort zone for lifting, and I know from experience that the horses can move much heavier weights this way than with an arch.

Now none of this is an argument against the arch. Just clarifying the difference between a conveyance and the horses ability to draw weight. The arch can play a very important role in the logging operation, providing safety to the operator, convenience, and comfort to the animal, but this does not replace the physics in play when a horse must work to lift a load.

Many may think this whole discussion to be pointless, but as I watch and listen to people discussing working with horses, I have to say that there are so many people coming to this craft from a modern cultural understanding that the fundamentals of the working animal are misunderstood by them.

This is one of my pet peeves, because this stuff was drilled into my head by men who had grown up working horses in the woods in a culture that had no other context from which to view the horse. The fundamentals of the working animal were fundamental to everything they did. Modern understanding of efficiency is blurred by the concept of proficiency. When working with animals every little “leak” of efficiency adds up, and the more we understand about the way the animals work, the better we will work them.

Carl

[Joshua Kingsley]

Joel,
I think that you have a valid point with the added weight.

There is the factor of not only the cart but at what point is the weight greater than the gain?
I have ground skidded for a while and for the beginning guy I think it is the best way to start out. You can gain a lot of perspective and then decide what works for you.
Just a green horns point of view.
Joshua

[Tim Harrigan]

Thanks to those who have added to this discussion. I am pleased to see how the scope has broadened to include the skill/training/conditioning/experience of the team. I look at the arch, go-devil, tongs and other methods as tools that can improve the comfort and productivity of our working animals when applied in the correct situation. Some of my thinking is translated from draft in farming to draft in logging which in some ways is fundamentally different. In farming we like steady endurance. We appreciate heart and determination when we ask for effort near the upper limit, but we try not to go there very often. We more frequently ask logging teams to ‘get after’ larger loads, often in tight quarters, and often in short bursts if just to haul out to a skid path for alternative handling, perhaps with an arch.

Carl is perceptive in describing how a good team gets under a load to both lift and pull (push) and get under the normal center of gravity so both strength and body mass drive the load forward. Starting a load takes considerably more effort than keeping it moving once started, so the upper limit is a pulse rather than a sustained pull, at least relative to the starting effort. The vertical lift and resistance of a heavy load transfers weight to the hind quarters of the team and acts to improve traction and power, in some ways just like ballast on the rear axle of a tractor. A low hitch point such as with ground skidding or a go-devil facilitates that. The ability to get under the load is a necessary tool for a good logging team.

It is beneficial to shift the line of draft to the center of gravity of the team as soon at the load begins to move. That is where the team will be most comfortable and efficient. Because an arch has a higher hitch point there may not be the same freedom for a team to get under or side-shift the load and create the instant when the load breaks free and forward movement begins. But an arch allows the same load to be started with less effort so the team will not be working as close to the upper limit when the log begins to move.

In my work with an arch I see a different dynamic that is important in starting the load, the pendulum effect of the hanging log. Because the front of the log is hanging at an angle there is weight transfer to the rear with ground resistance at the far end. When the team steps into the load the arch moves an instant before log moves. The front of the log moves back and up slightly, then when momentum begins the log swings down and forward, and under some conditions almost gives the cart a push. This cushions the start and my guess is reduces the peak force needed to start the load.

So, Carl, my reason for writing the article was not to promote the arch or any other method of handling timber, rather to measure the pulling forces for a range of tools as objectively as possible. I think I understand your concern that pounds-force does not surround all the important considerations, but I am convinced that pounds-force is a very important crosscutting reality and that our animals would benefit if more folks had a better understanding of the loads that they ask their animals to move and the tools available to ease the burden. I still come back to the ‘tool box’ analogy. An arch is a tool, as is a go-devil, tongs or a nylon tow rope. A craftsman has many tools in his toolbox and uses them as needed to accomplish the task at hand. These are tools that were designed by craftsmen with an understanding of the forces applied to their working animals, tools that enhance horsemanship and in no way reduce the process to a number. Regarding the arch, there may be a loss of efficiency on the top end such as you described, but I suspect there is a net gain in not having to ask for more effort than necessary in other parts of the system.

It is good to be suspicious of numbers such as I presented, I always am. Reports of these kind of measurements are not widely available for comparison, so I did the best I could and described the test conditions as accurately as possible. I was encouraged a few years ago when I read in RH an article either by or quoting another horse logger, Glenn French, I think, that by his estimate and compared to ground skidding he could increase the size of a load by 1/3 and move it with the same effort, or move the same load with less effort. Presumably, that was learned through many hours in the forest. I was pleased that our measurements matched his assessment almost exactly.

Again, I truly enjoy the perspective and observations of Carl, Jason, Scott and others that test these realities on a daily basis. You guys are the experts; I am mostly an innocent bystander.

[Tim Harrigan]

Joshua and Joel:
Regarding the weight of an arch, the one we used was 750 lbs, not including the teamster. But that is on wheels and moved much easier than skidding. I could roll the arch, pretty hard pressed to skid a 750 lb log by myself. So even with the additional weight of the arch we figured we could increase the size of the log by 1/3 and move it with the same effort.

[Joshua Kingsley]

Here is a picture of the little guys working in harness some today. They were hot and mad partly because I was having a bad day and the neighbor was sighting in a new rifle. hopefully I will get to the woods in the next couple of days again. Last time I didn’t have anyone to snap a few photos.

[Carl Russell]

Looking good Josh. My 7 yr old Timber wants a team just like that.:eek:
Carl

[Joshua Kingsley]

carl,
he might not. these little guys are more of a hand full than my big stud ever was. I think that it has to do with how small they are and how quick they can move. I always thought that they would be great for our two little boys but now I think that we might just stick with the Suffolks for now. If these two sell then I may try again with some mares or something in the future when the boys are a little older and want a team. I have had my hands full starting this pair of little studs that are together most of the time and now wish that I had found at least one with some driving work done before II started and paired them up.
There is always something to keep things interesting, now to get to work on the little 2 week old filly and her mom…:) the temperment difference is huge between the drafts and these little guys.
To be honest though if I didn’t have big horses these would keep me busy for sure.

Joshua

[TaylorJohnson]

Man they look like fun . What would you do with them if they were a ton a piece? I bet they would really be fun then . Good looking little team. Taylor Johnson

[Plowboy]

Josh,
I have friends with minis that also raise 17-18h Percherons. They have the best working mini’s I have ever seen, all business and puppy dog gentle. They even show a six-up of them at their hometown fair. He started training them because his wife was intimidated by the big horses so he got her a team and trained them. He says you don’t want to holler, get nervous or spank them or it makes the pony come out and then you can have your hands full. If they are full of themselves try working them on a big truck tire or small tractor tire and let them work it out for themselves.

[Joshua Kingsley]

They are fun the thing that I have found is like you said if you are even a little fustrated or upset you might as well put the littel guys up. My belgians that were over a ton each were a lot easier going If I was upset they would help me calm down and get through the issue. The ponies on the other hand just get MAD. I have a flotation tire that weighs over 100# and they are going ok with that. One other thing I have against me is 1 they are studs, 2 they are both partially blind due to things that happened prior to me getting them and 3 they were both abused at one point in time. All in all they are still good boys. I just would like to start a team of mares it is either that or at least one of these two are getting gelded. Time is on my side though I have a fella that is interested in them so you never know.
Joshua

[Tim Harrigan]

This post got me thinking about some work we did at Tillers International a few years ago measuring the pulling forces with a 1900 lb log on a sled. We compared standard traces with nylon tow-rope type traces and for each of those we measured the forces (at the sled connection) pulling up an 11% slope, on level ground and down the slope. The surface was firm hay ground. Check out a graph of the results with a picture in the photo gallery in the working horses section. The team is using the nylon traces in the pic.

Basic theory in physics tells us that the force needed to move a sled up or down an 11% slope is equal to the force needed to move it over level ground plus or minus a percentage of the gross weight of the sled equal to the percent slope. An 11% slope is a 1.1 ft rise in 10 ft of horizontal run. The basic idea is that up a slope you are dragging the load plus lifting it 1.1 ft for every 10 ft. Pulling it plus lifting 11% of the load as you move along. Or dropping 11% of the load on the downhill run. In this case we had a 1900 lb log with a gross weight of 2200 lb including the sled and driver. On level ground with std. traces the average pulling force was about 875 lbs. Up-slope was about 1100 lb and down-slope about 650 lb. 11% of the load GVW was about 240 lbs. Check it out: 875 + 240 = 1115 lbs, we measured 1100. 875 – 240 = 635 lb, we measured 650.

The pull on level ground was about 38% of the gross weight, pretty consistent with sled, scoot and stoneboat measurements we have made over similar surfaces. We made the measurements with a pull-meter on the sled. The pull meter was linked to a GPS and the pulling forces were measured 5 times per second and stored in a handheld computer. We pulled up and down the hill in the same location with each set of traces.

The pulling forces with the nylon tow rope are noticeably higher. The sled itself is not harder to move because we changed traces, but the measured forces that the horses push against are consistently higher with the nylon traces compared to standard traces when we move loads that create real resistance. Interestingly, we typically measure lower forces when we use teh nylon traces to pull a wagon with pneumatic rubber tires. I do not know how the pulling forces with the nylon rope pulley systems for plowing compare with standard traces. It would be interesting to measure sometime.

The downhill pulling forces, about 650 lbs, are about what we would expect with a 12 inch moldboard plow six or seven inches deep on our sandy loam soils. So this sled is a stout load on level ground. This nicely illustrates the difference between what we ask of farm teams and logging teams. We generally ask farm teams for a lower level of exertion but keep it going. We more often ask logging teams to really get after it, but for shorter distances and probably with more rest in between. Of course, many farm teams are fine in the woods but they might not be exactly what Jason or Carl or Scott have in mind. I think good logging teams go to work each day with a little different attitude than most farm teams. Just guessing.

Many folks ask how much can a team pull. Seems to me a more important question is how much are they pulling.

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