T post and cedar post intervals for over 5 thousand feet of fence.

I am still in the planning stages of a pretty big fence project. My place is in open range, and there are cows everywhere, thus I have to fence them OUT. (That's the way open range works in the western U.S.) I'm not really looking to keep too many critters in as of yet.  I am looking to fence off a little over 36 acres and will have to build a little over 5 thousand feet of fence.

The terrain has enough rises and falls (about 50 feet in height) that the end posts cannot be seen from one another however they can be seen from the rise. I was going to use the old roman method of a board with two nails in it, and walk the line in to get the fence lines established.  It has worked before for me and has been highly accurate. Some times old tricks are the best ones in my humble opinion.

I have built fences in Colorado with cedar posts but due to the sheer size of this project digging 500 post holes for wooden posts isn't really high on my list of fun stuff to do so I will be running metal T posts for the line posts.
I will be putting in Cedar posts on top of rises and in the bottom of low areas. I have runs of 1250 feet, 1550 feet, 880 feet and about 1550 feet respectively.

My question is concerning the metal T posts. Is there any real accepted ratio of T posts to wood posts? I was thinking metal T posts about every 11 feet and a cedar post about every 110 feet or so, making about 11 posts for a 1320 feet run of barbed wire. I don't know if this is close enough or too far apart. Any wisdom would be much appreciated. Thanks in advance for your time.

Never be afraid to try something new, remember-amateurs built the ark, professionals built the Titanic.

Tim,

36 acres is a lot of fence!  And no small budget.  I don't envy you.  About 10 feet between t posts would be about my limit, if I wanted to keep cows out.  11 is close enough, but you may want to add additional later.  How many stands?  How strong is the browse pressure outside the fence compared to what you are protecting?  Cows won't push through a fence without a reason, but the better your side looks compared to what they are feeding will determine how much they lean on or through your fence.  4 strand minimum.  5 better.  Go 6 is they absolutely have to keep out.  Once they can get their head through, they can push through wire if they are hungry enough.  

When you use the old Roman method, how do you establish your azimuth without line of sight.  I am curious.  We had a discussion on premies recently about this very topic.

https://permies.com/t/54050/Fencing/project-ft-straight-fence-straight

I just this fall completed a 160 acre perimiter fence in Colorado with t-posts, I was helping my neighbors and he is far from worried about exact feet between fence posts but what he did was every 15 steps he put a post. Like I said far from perfect but its kept his 4 horses in and everyone else's cows and horses out so for now its working well. Where at in Colorado are you? I have 45 acres myself but only 3 are fenced, I just can not afford it. Good luck with the fence!

Jack and Jade, thanks for your input. The land I am fencing in is in Northeastern Arizona. I am leaning toward 5 strand as the area is borderline overgrazed at the current time. As cows are fenced off and it recovers, I know the browse pressure will only increase so I am planning on putting in staves or go electric if need be. I am going to put in a cedar line post about every 100 feet or so with metal line posts every 10 feet.

I grew up on a fruit orchard on the Western Slope of Colorado near Cedaredge. Pretty country, but way to expensive for me to live there now.

The Roman method requires you to be able to see both ends from somewhere in the middle, don't be fooled the low tech approach though, it is uncannily accurate. I recall using a 2 by 2 that was about 4 feet long, we placed a finishing nail in each end and used an old camera tripod to hold it. Because you are in the middle and can see both points, no azimuths are needed, and because the nails are on opposite ends of the board there is a 180 degree difference between them, even if the board is a bit warped. It works well where there is a rise and you cannot see one end point from the other end point, or if you can see both end points and you are trying to get on line somewhere in the middle.  Consistency is the key and keeping it attached to the tripod was a bit of an ordeal. Here's how it works:

1.) start by guestimating where your point is supposed to be on line and set your tripod there. Almost guaranteed you'll be off by a bit.

2.) Sight in one end point by standing on one end, looking down the board and rotate it on the tripod until both nails line up with the point. Once they are sighted in, DO NOT MOVE THE BOARD yet. It has to be still for the next step to work.

3.) Go around to the other end of the board and look down it, your other point will either be to the left or the right of your line of sight lining up the two nails. If the point is to the left of your line of sight, you will have to move your tripod to the left. If it's to the right, move your tripod to the right. Good starting rule is to estimate how far to the left or the right you are, then split the difference. Don't be surprised if your first move is 10 feet or more on a long run.

4.) Reset your tripod and start over again. Sight one end in, run around to the other end of your tripod and see how far your line of sight is off, and move accordingly.  Eventually your moves will be smaller and smaller and you will get to a point where both ends line up without moving your tripod. That's how you know you are now on line with the ends. This is known as "wiggling in" and has been used for years by surveyors. No azimuths, no back azimuths, no math, = reduced chance for error.

It can be a bit of a Pain in the behind to get right, but as with anything practice makes perfect. Hope this helps.

Tim