Art and Science of Rope

This chapter presents an introduction to the archaeological and historical aspects of various uses of rope and techniques of making rope. There are two main types of rope, laid rope and braided rope, where the former one is in focus in this chapter. Mathematical and physical properties of rope and how to adapt these properties when making rope are discussed. The focus of these properties lies on those that fulfill the requirements put on rope made for decorative purposes with some additional comparison with rope made for practical use. A laid rope may be described as a helical structure due to its spiral shape. That is, each strand of the rope can be seen as a symmetrical circular helix, with the helix curve as a central line within a rod or a tube of diameter dt, forming a strand. A rope of n strands is denoted as n-helix. This view can be used in studying some of the properties of rope. A rope is perhaps even better described as a super helix, which is a structure where each of the strands in themselves consists of parts (yarn) that are twisted like helices. The basic idea with rope is rather simple, and its structure may at first look primitive, but the mathematical models needed to fully capture the properties and characteristics are indeed rather complex. However, for the modern rope maker, equations based on approximations for calculating, for instance, diameter and length, are more than sufficient.