The paper presents and discusses a nonlinear, three-dimensional, finite-segment, dynamic model of a cable or chain. The model consists of a series of links connected to each other by ball-and-socket joints. The size, shape, and mass of the links is arbitrary. Furthermore, these parameters may be distinct for each link. Also, the number of links is arbitrary. The model allows an arbitrary force system to be applied to each link. The model is used to develop a computer code which consists primarily of subroutines containing algorithms to develop the kinematics, force systems, and governing dynamical equations. Although the integration of the equations is performed with a Runge-Kutta algorithm, the code is developed so that any other suitable integration technique or algorithm may be substituted. The input for the code requires the following: the number of links; the mass, centroidal inertia matrix, mass-center position, connection point, and external forces on each link; and the time history of the specified variables. The output consists of the time history of each variable, the position, velocity, and the acceleration of the mass-center of each link, and the unknown forces and moments. An example problem is presented which describes the motion of a sphere drug through water by a partially submerged cable suspended from a rotating surface crane. Viscous forces of the water are included. Although the example simulates a typical nautical rig. its inclusion in the paper is introduced primarily to illustrate the capability of the model.