In the design of a multi-legged point moored system for a ship, the two primary design requirements are the maintenance of the ship in a prescribed position during operational conditions and the survival of the vessel in extreme weather. It is usually convenient to divide the analysis of a ship mooring system into two separate tasks: (1) The prediction of the steady-state configuration and tensions in the mooring lines due to wind and current forces; and (2) the evaluation of the dynamic response of the system including the fatigue loading on the mooring cable caused by the oscillating forces of the sea. The first case has been adequately studied in the past and it is the dynamic aspect of the mooring problem in a hostile sea environment which is studied in this investigation. The ship mooring problem requires the combining of the dynamics of the ship system with the attached mooring cable system. A considerable amount of theoretical work has been done on the seakeeping aspect of a freely floating ship in ocean waves. In addition, work has been pursued in the area of cables and cable systems. In this paper an analytical study is made of the complete coupled problem of a ship moored system in waves. This includes an assessment of the various methods of analytically simulating the components of the complex cable system in the time domain. Specifically, differential equations characterizing the four degrees of freedom of the ship in the transverse plane (surge, sway, yaw and roll) are combined with the catenary equations to form a nonlinear dynamic system.

Media Info

  • Features: Figures; References;
  • Pagination: p. 67-96

Subject/Index Terms

Filing Info

  • Accession Number: 00035978
  • Record Type: Publication
  • Source Agency: Marine Technology Society
  • Files: TRIS
  • Created Date: Oct 20 1973 12:00AM