THE MOTIONS OF A MOORED SHIP IN WAVES

This thesis formulates a mathematical model which can be used for computer simulations of the behaviour of a moored ship in waves. An extensive experimental verification has been carried out by means of model tests, for a 200,000 tdw tanker in shallow water (the keel clearance amounted to 20 percent of the draft). Comparative computations and measuremens of wave loads, hydro-dynamic restoring forces and free floating ship motions have been carried out. Further, computer simulations have been made for the case that the ship is moored in regular and irregular waves to a jetty, by means of mooring lines and fenders. The results of these computations are also compared with those of model experiments. An analysis of the results obtained shows that the typical behaviour of the moored ship, with subharmonic motion response, is represented adequately by the mathematical model. In conditions where the ship is pushed against the fenders by the waves, the subharmonic motions are caused mainly by the non-linear characteristics of the mooring system. When the angle between direction of wave propagation and the longitudinal axis of the ship is small, or in case the ship is pushed away from the fenders by the waves, it appears that the second order wave force has a dominant influence on the low frequency motions of the moored ship.

• Corporate Authors:

  Netherlands Ship Model Basin

  Haagsteed 2, P.O. Box 28
  Wageningen,   Netherlands 
• Authors:
  • Van Oortmerssen, IRG
• Publication Date: 0

Media Info

• Features: References;
• Pagination: 138 p.

Subject/Index Terms

• TRT Terms: Force; Mathematical models; Mooring; Ship motion; Simulation; Waves
• Uncontrolled Terms: Wave forces
• Old TRIS Terms: Moored vessels
• Subject Areas: Design; Marine Transportation;

Filing Info

• Accession Number: 00159950
• Record Type: Publication
• Source Agency: Netherlands Ship Model Basin
• Report/Paper Numbers: No. 510
• Files: TRIS
• Created Date: Sep 20 1977 12:00AM