The most common method used in determining or laying off linear measurements for construction surveys, triangulation base lines, and traverse distances is often referred to as CHAINING. The name is carried over from the early days when the Gunters chain and the engineers chain were in use. Today, it is more appropriate to call this operation TAPING because the steel tape has replaced the chain as the surveyors measuring device. In this manual, however, chaining and taping are used interchangeably.

Identifying Duties of Chaining Party Members

Obviously, the smallest chaining party could consist of only two peopleone at each end of the tape. To lay off a line to a desired distance, one person holds the zero end of the tape and advances in the direction of the distant point, while the other holds a whole number of the tape at the starting point. The person ahead, holding the zero end, is called the HEAD CHAINMAN; the other person is known as the REAR CHAIN-MAN. In ordinary chaining operations, if the distance being measured is greater than a tape length, it is necessary to mark the terminal point with a range pole. In this way, the rear chainman can keep the head chainman aligned at all times whenever a full tape length or a portion of it is transferred to the ground.

The head chainman also acts as the recorder, and the rear chainman is responsible for keeping the tape in alignment. If more speed or precision in taping is required, additional personnel are assigned to the party. This relieves the chainmen of some of their duties and permits them to concentrate primarily on the measurement.

For more precise chaining, a three-man party is essential. In addition to the head and rear chainmen, a stretcherman is added. The duties of the stretcherman are to apply and to maintain the correct tension on the tape while the chainmen do the measuring. The head chainman still acts as the recorder and also reads and records the temperature of the tape.

Either of the two chaining parties described may have additional personnel assigned as follows:

. A recorder keeps a complete record of all measurements made by the taping party, makes any sketches necessary, writes descriptions of stations and reference points, and records any other data required. The head chainman or the chief of the chaining party may perform these duties.

. A rodman sets a range pole at the forward station to define the line to be taped, drives stakes to mark stations and reference points, carries the taping stool (discussed later) to the forward point, and performs other duties as directed.

. One or more axmen clear lines of sight between stations, cut and drive stakes, and perform other duties as directed.

. The chief of the chaining party directs the work of making the tape measurements, the establishment of stations, and other activities of the party in the field. The head chainman performs these duties when there is no separate party chief.