[Tim Harrigan]

JAC: I have done a fair amount of work measuring draft forces with various tools and implements. First I have to say I have a few concerns about the Peace Corps articles mentioned by Sabine. There are some real misinterpretations in that document. The most serious is that it takes a force of 30 kg to move a 30 kg load. Perhaps 30+ to lift it but not drag it. Dragging a load on a sled or stoneboat on firm ground like pasture or hay ground will take a force of 30% to 40% of the gross weight of the load. So it will take about 30 kg force to move a 75 kg load. Some of the other tabled draft estimates are suspect as well but its not important now.

Sled and stoneboat draft is very predictable and that is one reason they are nice training and conditioning implements. I often encourage folks to think in terms of equivalent loads when preparing a young farm team to plow. Draft in the range of 600 to 800 lbs is pretty typical for a 12 inch bottom 6 inches deep around here. If you use the general rule-of-thumb that 40% of the gross weight will go to force in the chain and you want your team to be prepared to plow you can create a equivalent plow load by loading the sled to a gross weight of 1500 to 2000 lbs (600/.4 = 1500, 800/.4 = 2000). If they pull that confidently they will have an easy transition to the plow. If they are not prepared and are faced with a plow load they will start jumping the furrow and causing problems to avoid the load.

Some of these draft issues have been on my mind because of some of the recent discussions. Just the other day I summarized some of the work I did with a sled and a 1900 lb log under a range of conditions. It is in the Sustainable Forestry section under the ground skidding thread. It considers uphill and downhill draft as well.

If you are interested in round baler draft that too is predictable. On firm, level hay ground with pneumatic tires the pulling force needed will be 5% to 10% of the gross weight of the baler. So if the loaded baler weighs 3000 lbs the average pulling force will be 150 to 300 lbs, not a big deal for a conditioned team of drafts. There is a summary of some of our work with logging draft that also included wagon draft in a technical guide linked to Jason Rutledge’s Healing Harvest Forest Foundation web site. http://healingharvestforestfoundation.org/ You can download a copy from there. Things you drag, things that roll, of course the pull will vary based on the surface and slope but the pull is pretty predictable. Wagons and balers that weigh the same will not be much different unless it is a ground driven baler.

The Peace Corps document takes a standard tractor-based approach to sizing a team and implement. That is you start with your high draft task, say the moldboard plow, and size it to accomplish the plowing in the days available before mud sets in or planting time, whatever works in your area. Then select your tractor hp and base the other tillage tools on the power available. That can be difficult to apply to animals because they are not a tractor. Tractors can go all day an only lose the time it takes to turn on the headlands. Horses abilities will be influenced by age, temperature, relative humidity, conditioning, tool adjustment and many other factors. We usually have excess power with a tractor so little thought is given to how tillage depth affects tillage draft.

Here are a couple of tillage draft maps that we made with horse drawn tillage tools, a 23 tooth spring tooth harrow for seedbed tillage and a 6 ft, single gang disc harrow. The pulling forces were measured with a pull meter and linked to location with a GPS. Then geographic information software was used to create the surface map. In each case we split the field in half to evaluate tillage depth or disc weight. The low draft half of the disked field was with the standard disk, the higher draft half was with 160 lbs additional weight added to the disk to increase depth. The low draft half of the spring tooth harrow field was with a 2 inch tillage depth, the higher draft was with a 3 inch depth. If you look in the northeast corner of that field you can see where we started with a 4 inch harrow depth, drafts in the 800-900 lb range. We went about 100 ft and I called it off, I did not think it was reasonable to ask the team to work a that level of effort throughout the day that early in the season.

I have noticed that folks really like to sink those springtooth harrows in the ground. Huge increase in draft with little or no improvement in seedbed quality.:eek:

[Tim Harrigan]

http://www.gpsworld.com/gis/imagery-aids-haiti-rescue-efforts-9408

Check out this article about another source of aerial images that might help you. The title of the article looks like it is about Haiti but that seems to be a mistake. Here is a like to the site that they discuss.

http://datagateway.nrcs.usda.gov/

[Tim Harrigan]

I promise you the horse learned more than anyone else that day.

[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.

[Tim Harrigan]

Just drag a small limb or branch. Give them a chance to get used to dragging something then move up from there.

[Tim Harrigan]

Carl, these are interesting thoughts and I admire you for making the effort to think through these linkages and articulate them to a group of students. You have raised some big issues that I will need to think through a little more. I did, though, listen to the SoF webcast that you suggested a week or so ago. One of the things that occurred to me is that farm families have had an active role in devaluing their profession by either actively discouraging their children from considering farming as a wise choice or perhaps wearing them down with long hours of physical labor and little recognition or articulation of the rewards. The schools have helped the process along by completely removing what was seen as vocational education from most systems. The shop classes that I had in high school and enjoyed so much have long ago disappeared.

Social predestination is certainly a reality is many areas of the world, but in our communities folks generally have real choices based on mobility and ambition to redefine their destiny. Education has been one of the options in that way and I have seen many kids from the farm go off ‘to college’ and not come back. So in some ways the range of opportunities in rural communities needs to be redefined and communicated in a way that is real and meaningful. It seems like a new set of possibilities is emerging for many that values honest and traditional skills by capturing the modern advantages of mobility and broader reach.

It seems to be a bit of a hobby for those with traditionally physical occupations to rip on ‘egg head engineers’ for instance and vice-versa. It is common for folks to build themselves up by diminishing the skills and abilities of others, and the less we know about the real depth of decisions that others are face with the easier it is to do. But it seems clear to me that the real winners are those that have had the opportunity or have made the effort to balance their lives with both physical and intellectual challenges. Formal education is not the only source of intellectual challenge.

I am guessing that for those who frequent this site, as we look back at those who provided real and meaningful inspiration regarding career and life choices, few look to those responsible for formal education. Some will, but I see faces much closer to home, farmers and the like who I saw day to day. Not a lot of formal education but so smart in so many ways. Would they make the same career choices today, given the stunning increase in mobility and options available just 2 generations later? Maybe, but probably not.

Intelligence is not obtained by higher education. Most of the fundamental work in designing most of our farm tools and implements was done in the mid-1800’s, most likely by folks with no formal education. Many of those tools have changed very little other than nice sheet metal and paint. And horse harnessing systems are an incredible example of observation of the forces transmitted to the animal and translation of complex concepts of physics in balancing those forces.

I love the line from Randy Newman’s song, Louisiana…”College men from LSU, went in dumb, come out dumb too…” I know for a fact that a lot of kids would benefit from opportunities to learn to do honest work with their hands and build real skills before they went off ‘to college’. It would be a life changing experience.

[Tim Harrigan]

Grey: I like your assessment.

[Tim Harrigan]

You have to decide what is most important. I know what things are most important to me and matched color or size are not near the top of the list. There are a lot of benefits to showing steers. The drawback is some of the superficial things that are important in the show ring are not at all important if you want a team that is responsive and works well, but those things become the tail that wags the dog. I know there is bound to be a lot of joshing around among teamsters, but if someone is critical of another team because they do not color match I guess you have to call on Homer Simpson to sum it up… “Lord help me Marge, I’m just not that bright”.

[Tim Harrigan]

Is it more important to you to have a team that works well or looks good?

[Tim Harrigan]

Carl Russell;14321 wrote:

At some point I came across a video in which a trainer was methodically elevating his energy, and then as soon as the horse did the big eye thing, the trainer would immediately lower his energy, regaining a calm posture. And the horse was glued to him. When I tried this I was floored…..and not only did I learned a lot about horses, but really I began to learn about myself.
Carl

Carl, this is interesting. I also do this from time to time with my cattle. They know they are to stand quietly and not try to graze in the yoke when I am away from them and working. But every day is a new day and a good pair are always wondering if the boundaries that existed yesterday still hold and is today the day they get to drive? So about once every year when the grass is high and I am away from them I will notice them try to grab a bite. I yell head up and they will, but they will start to push it. So after three or four warnings I just drop everything, don’t say anything, and here I come, full speed. They start dancing as soon as they see me coming and I really get in their face. Not mad, but quite a show. Then it is over. I go back to work, they stand and wait. The next time I yell heads up they both look up at the sky.

When I first started working with cattle I was concerned when I would notice them challenging me in subtle ways. Now I know they find comfort in knowing that yesterday’s rules still hold and a good team has a need to know. I might find it hard to fully appreciate a team that never pushed on the edges a little bit. You just have to know when and how to push back.

[Tim Harrigan]

An easy and inexpensive alternative to a stoneboat is a sled. You just need a couple of 4×4’s and some 2x across the top to form a solid platform. I like them about 3 ft wide and 8 feet long for most general purpose work. Stoneboats are nice but you need to fashion a head out of something or buy one so you may want to start with a sled and look around for stoneboat parts.

[Tim Harrigan]

Check out the Web Soil Survey
http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

This is a free site maintained by the USDA NRCS. You can get detailed soils information with some really good aerial images. You outline the parcel of interest and get good acreage estimates and you can indicate the map scale you are interested in. You can also request information about land productivity including forest resources. The maps are referenced in UTM coordinates. Really some pretty good stuff if you take the time to learn how to exploit the full capabilities of the site.

The quality of the aerial images vary with location, I just checked a random forest location near Middlebury VT and it was not that great. We have great images for Michigan, mostly farm country here. Good stuff though if you have clear aerials.

[Tim Harrigan]

You need Geographic Informantion system software. I have one that I use often for other purposes but it was not free and I do not know if there is any free stuff out there or not.

[Tim Harrigan]

The yoke and bows look great. Get as far as you can before you leave. In 12 weeks they will be a hand full but you will be fine. Most teams do not get much work in the middle of the winter anyway. Good luck.

[Tim Harrigan]

I learned early on that driving an ox team from in front or the point of their shoulder was not a good idea when skidding out logs. You can get your feet tangled in the brush, catch your goad or whip in brush or overhead branches, step in a hole or trip over debris, and there are too many pinch points for my comfort. It is not fair to ask a team for a good effort and expect them to watch out for you at the same time. You underestimate a team if you think you need to show them every step of a 50 ft pull to a skid trail. In those situations I point my team in the right direction and drive from behind by voice. Like Carl says, stay behind were you are safe and you can see what is going on, and advance the load in stages. My team, and probably most teams, are very responsive to ‘whoa’ when they are on a load. They are more than happy to stop. That is when you make your adjustments, not on the fly while crashing through the brush. They know when I am helping and when I am a hindrance, and it really annoys them when I am not helping. Up in front or at the point of the shoulder is a scary and dangerous place to be when you are off the skid path.

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