This paper describes a stand-alone PC-based computer simulator for mooring design and operations. Both program logic and mathematics are discussed. Competing algorithms for solving several classical mooring problems are compared. The program contains a design module, static and dynamic mooring simulators, and mooring calculator modules. The design module performs an automatic optimum design of anchor deployment for any environmental condition, or allows the user to perform an interactive design. The static simulator predicts system responses in all mooring operations. The dynamic simulator is an implementation of the recent requirement of regulatory bodies for simulating slow-drifting motions of the vessel after a line failure. The calculator includes modules that compute weather forces, system stiffness, elastic catenary mechanics, and others. The program is interactive, menu-driven, and includes graphics.