RELATIVE ROLL MOTION OF A SHIP IN BEAM SEAS

The effects of the entrapment of water on the deck of a ship in regular beam seas are studied by experiments and a simple one degree of freedom theory. In the theoretical analysis the resulting equation of motion is solved for the relative roll angle between ship and wave surface using an equivalent linearization of quadratic roll damping. A computer program is developed to evaluate the amplitude of the relative roll angle as a function of wave frequency for various ship and wave input parameters. A systematic series of ship model experiments was conducted in the University of California Ship Model Towing Tank for the purpose of testing the theory and studying effects which are outside the range of applicability of the simple theory. In this way it is possible to isolate those ship and wave parameters which cause large relative roll motions and particularly the effect of entrapment of water on the deck of a ship. Qualitative observations of the ship model during these preliminary tests offer some insight into the dynamic effects of water on deck and on the tendency of the ship to capsize in beam seas.

• Supplemental Notes:
  • Paper presented on 8 March 1979 to the Northern California Section, SNAME.
• Corporate Authors:

  Society of Naval Architects and Marine Engineers

  601 Pavonia Avenue
  Jersey City, NJ  United States  07306-2907
• Authors:
  • Visineau, G
• Publication Date: 1979

Media Info

• Features: References;
• Pagination: n.p.

Subject/Index Terms

• TRT Terms: Capsizing; Computer programs; Engineering moments; Fishing vessels; Rolling; Ship motion; Wave height
• Old TRIS Terms: Model testing; Roll amplitude; Rolling moment
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00316703
• Record Type: Publication
• Report/Paper Numbers: Conf Paper
• Files: TRIS
• Created Date: Oct 8 1980 12:00AM