Surveyors apply technological advancements to enhance services and improve delivery schedules while maintaining reasonable cost. However, low-tech solutions of the past are sometime better than the sought-after, sophisticated high-tech solutions.

The best example of a low-tech solution is the plumb bob. In use for thousands of years, it always tells up from down using a reliable source: gravity. A pointed weight attached to a string has no batteries, no language barriers, no codes, no conversion factors, and no complicated directions to follow. And it can save money.

When the historic, 130 year-old Cape Hatteras Lighthouse was moved inland to protect it from an eroding seacoast, leaning was a primary concern. A sophisticated, $250,000 electronic system was designed to monitor the tilt and tip of the 200-foot, 4,800-ton structure. Survey crews were hired to monitor the horizontal and vertical movements with a robotic total station.

However, electrical storms, power outages and damp weather plagued the sophisticated tilt and tip sensor system. At one point, this system reported that the lighthouse was leaning. As the contractor began corrective jacking, survey crews using the total station reported the lighthouse was leaning in exactly the opposite direction.

The expensive electronic system was abandoned and replaced with a tried and true method: a five-pound plumb bob hung in the middle of the lighthouse with a target underneath. Now, checking the amount and direction of lean was as simple as looking at the plumb bob.

The plumb bob has many uses. Hung in hydraulic fluid, it can transfer horizontal positions over great vertical distances. In a deep mine shafts, this can be used to lay out mine or tunnel surveys. A modified plumb bob (a steel tape) hung vertically with the lower end weighted for stability can determine elevations for multi-story structures and bridges. In an existing building, a tape can be hung in a stairwell. Once the tape is correlated to a known instrument elevation, the tick marks on the tape can be used to compute elevations. The tape and gravity method simplifies the process and provides cost effective, reliable results.

High-tech applications may provide unique results, but dont forget to embrace the proven low-tech methods that can attain cost-effective solutions.