[Tim Harrigan]

OK, Andy, you head northeast and I will head south to SDAD. Looking forward to it.

[Tim Harrigan]

Yes, I generally expect plow draft at 600 to 800 lbf compared to 400 for the 6 ft mower. Plow draft will be a lot more variable. Draft in the same field can easily double throughout the year as the soil changes from moist and friable to dry and consolidated. I think I showed the results of plow draft measurements somewhere in this working with draft animals category. If your team is conditioned for plowing they should be ready for mowing.

[Tim Harrigan]

No, not in one day. First day you cut and start drying, second day cut more and start drying, third day cut and then rake what was cut on day one, next day cut, rake what was cut on day two, bale what was cut on one. That would be ideal, probably take even longer for cut 1 to dry, just depends on the weather. You do not want to be caught with too much hay on the ground if it rains and those days when you have to cut, rake, bale, haul, unload and stack are going to be long days.

[Tim Harrigan]

Knock down one acre per day and see how it goes. You will have days when you have to mow, rake and bale on the same day and you are going to have to work around the weather.

[Tim Harrigan]

What kind of shape are they in? How much hay do you have? How do you plan to rake and bale or gather it? How far do you have to haul it? Anybody helping you? Is your mower in good operating condition? How may hours a day do you have for mowing? Got rocks? Got hills? How hot is it? Mow in lands or around the field? Got any point rows?

[Tim Harrigan]

It has crossed my mind in the past that he may be lowering his head to improve his vision of me. So it could be this is more common with the off ox. Maybe switching sides would change how he carries his head. I think if they carry their head low to see the teamster and it becomes a habit, that would be hard to change. He also carries his head low when I drive from behind and ride on the stoneboat or sled. He has to lower it to see past the yoke. So these things could contribute to his behavior, but on the other hand, he has tended to carry his head low since he was quite young, at least six months old.

[Tim Harrigan]

That is a good question. With my team it is the off ox who likes to carry his head low.

[Tim Harrigan]

http://www.draftanimalpower.com/showthread.php?t=224

There was some discussion of this a while ago. If you read about this you may get the impression that this is a problem that is easily corrected by some some adjustments in the bows, etc. But it looks like at least Rob and Vicki and I have had steers that just seem to prefer to carry their head low and bow adjustment does not have much of an effect.

I guess it is a little annoying but as long as they are pulling well it is not a practical problem. I can sure think of a lot of habits that would be a lot worse than carrying the head low. Perhaps if you were pulling loads frequently that were near the upper limit of their ability some problems might be revealed but I am not sure of that.

Have you tried a three pad collar?

[Tim Harrigan]

I am not sure if there is a source in Canada or the US.

Claude Fanac
Schlosserei/Schmiede & Apparatebau
8588 Zihlschlacht
Switzerland

Tel 071/422 4745

[Tim Harrigan]

http://www.fanac.ch/zep.htm

http://www.fanac.ch/zep-f-.htm

Here is and English translation,
http://translate.googleusercontent.com/translate_c?hl=en&ie=UTF-8&sl=de&tl=en&u=http://www.fanac.ch/zep.htm&prev=_t&rurl=translate.google.com&usg=ALkJrhhrCF–Akti8qqNHTVbnr_J-HWjog

[Tim Harrigan]

In my test I started with the chain, made 6 starts with short pulls and then made a steady pull for about 1600 ft. Then I swapped the chain for the nylon rope and did the same thing. So I would say the team knew what to expect. There are a lot of variables associated with starts and because they are of such short duration I am not sure we will sort it out, particularly when the differences are small such as I think we see here. It is not easy to measure physical systems that are under biological control. I still think one would need additional sensors to measure pressure points etc. and probably still be left with more questions than answers.

For our purposes, at some point it has to pass the test of practicality. Does a buffer clearly make a difference, and where and when? A start is a sort of shock load just like a rock or other stationary object, but the team has some control over a start. Even if you vary the load they still assess the load the instant they begin to step into it. I have seen my team very quickly make a distinction between a heavy load and a fixed object. And they did not have to slam into the load to do it. It is actually quite impressive what they know about a load.

This is a reason I liked the frequency of pulling force charts that I showed earlier for the wagons. The rubber-tired wagon passed both the test of statistical significance and the test of a pretty clear practical difference. You can have a little more confidence in the assessment when you are looking at 5000 measurements over 1/4 mile or so rather than 5 measurements over 1 second. The starts could be done, I just think it might be beyond the scope of what we can do these limited measurements.

[Tim Harrigan]

Yes, I agree that the animals will adapt to the load and I was concerned about that when I was doing the tests and that was why I only did six starts. I think I mentioned this ability to adapt in regards to the front-to-back load shifts that I posted earlier where the draft increased at different hitch angles when the load shifted from back to front when pulled with a tractor, but there was no change in draft when Will and Abe pulled the load and the load shifted back to front.

There are trends in the starting forces, I checked and I started with the chain and then went to the nylon rope so there could have been some adaptive behavior that makes me suspicious of jumping to conclusions in interpreting what is really going on.

I do not doubt that the draft buffer concept is valid and I appreciate your close inspection of the data but I have been trained to be skeptical. I have 4 nylon traces but I do not use them. If you want to try a set I can send them to you for testing.

Here is a picture of the nylon rope. The dense rubber insert is compressed when the rope is under tension.

[Tim Harrigan]

I enjoy your enthusiasm for the analysis, and there probably is a small buffering effect. I would be more comfortable with the statistical component with more control over the dependant variables. I would like to see more contribution to the 1500 ft pull to help get over the ‘practical benefit and worth investing in’ test.

[Tim Harrigan]

The peaks were from this data. You will notice that I changed the symbols now in the graph, the circles were obscuring some of the diamonds in at least one instance. I did report incorrectly though, average starting peak was 614 for the nylon and 664 for the chain. I will email you the data file so you can look it over a little more closely. The average draft was from a 1500 ft pull with each towing device, not from this graph. Give the variability in the numbers, only six starts, and the inability to start the team exactly the same in each case I might need a little more convincing than what I see here.

[Tim Harrigan]

I was curious to see if the nylon rope would provide more buffering of sled draft under less resistance than a sled on bare ground so I did some tests in January when the ground was frozen and 3 inches or so of snow. The attached graph shows the pulling forces for six starts and a 5 second pull with a 1000 lb sled (scoot). The starting forces spiked to an average peak of 614 lbf for the nylon rope and 664 lbf for the steel chain. The average continuous pulling force once the sled was moving was 77 lbf with the steel chain and 80 lbf with the nylon rope. Even though the starting chain draft is higher I do not think the difference is large enough with these 6 comparisons to conclude there is a real and predictable difference between the chain and the nylon rope.

There are some interesting things about this. One is the surprisingly high starting spike that lasted about one second. I do not think it actually took this much force to start the load, but neither was I holding them back to ease slowly into the load to miminize the starting spike. It shows me that a if yoke fits well the team will not hesitate to step into and accelerate the load. If a team is reluctant to start a load there may be an equipment problem, or the load may be too big for the team to handle confidently.

Also, once the load on the sled began moving and developed momentum it required only a small effort, a pulling force equal to about 8% of the total weight of the load, to keep it moving. This is about the same effort needed to pull a steel-tired wagon of the same weight. So a sled or scoot is a very efficient method of conveyance on frozen and snow covered ground. The frozen ground was important, the sled runners did not cut in the ground which would have increased draft. Also, the snow was only a few inches deep so the sled was not pushing snow. That also would have increased draft.

It reminds me of the work we did measuring logging draft with tongs. The draft when skidding a log on bare ground was actually lower than when skidding on snow covered ground when the ground was not frozen. The log not only cut in similar to the bare ground, it plowed snow in doing it.

[Author]

Posts