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Apprehensive Level Run
I had a two-mile level run that had to be done on an emergency basis for an important client. I had no one to delegate to the job, so I did it myself, and I had to use an inexperienced rodman, MY WIFE Gretchen! She had never held a philadelphia rod and had never helped me on a survey of any kind. The wind was blowing, and the traverse was in hill land, and we were late getting there having followed a funeral procession. I had not noticed until we were almost to the job site when I saw that Gretchen had on loafers that probably had never even touched grass. I made her put on some size 12 rubber boots I had in the back of the truck (5 sizes too large). I showed her how to hold the rod level, but the wind was blowing. I almost packed up and headed home, but instead I just remained grouchy, and tried to do the work. When I took first backsight when she was on the BM, the rod was tilted, and when I told her to hold it straight, she argued that it WAS straight. I used the vertical reticle to insist that she tilt the rod, and we ran the first leg and closed back just as a check, and it was way out of tolerance. Instead of quitting, I helped her with the vertical reticle guidance by waving my arms (politely), and showed her how to rock the rod back and forth so that I could select the lowest reading that I could see as she rocked it, and I used that. I know that rocking the rod is a good procedure to improve the quality of a level run, but I had never really required rocking it to the extreme that she did. I felt like a bidder looking for the lowest price as I would get her to hold rod vertical, and I’d bracket the high and low and then start seeking lowest reading as she continued to rock the rod. We finished two miles of level run in hills and wind and actually did significantly better than the allowable tolerance. I couldn’t believe it, but we did it.
That exercise reminded me of good level run technique, the most important of which is in my opinion, rocking the rod and keeping the foresight and backsight distances fairly close to each other. I had one crew for years that just never could close vertically like the others, and I wonder if he had his rodman rock the rod. I have seen many level run crews, including many that were not my employees, and I never really saw them rock the rod much, if at all. For the very few of you who might not know what I am saying, the concept is that the very lowest reading you can get on the rod is when it is perfectly vertical.
Anyway, we ended up with a good level run and did not choke each other. I cannot say enough about how rocking a rod can help attain an accurate level run, not matter how great or little experience the rodman has–way better than a level vial. Wanted to pass this silly little thing along in hopes that many will be reminded to rock the rod! 🙂
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