THE RELATIVE MOTION BETWEEN SHIPS IN RANDOM HEAD SEAS

As part of the Navy's program to develop mobile port facilities, an analytical model was developed which can be used to compute the relative motion between vessels in regular and random head seas. The model, based on strip theory, is suitable for analyzing all single hull, linearly moored slender vessels. Since symmetry of moorings (if present) is assumed throughout, the motion is restricted to heave, surge and pitch. Deep-water added mass and damping coefficients are used in the equations of motion, and the resulting model predictions are considered valid provided that the draft-to-mean depth ratio does not greatly exceed 0.50. Typical results from the analysis are presented. These include graphs and tables of: the relative horizontal and vertical motion between two moored oceangoing vessels in shoal water, the relative horizontal and vertical motion between a moored ship and an unmoored beach discharge lighter, and the shoal water surge response of vessels as a function of mooring stiffness. (Author)

• Corporate Authors:

  Naval Civil Engineering Laboratory

  Port Hueneme, CA  United States 
• Authors:
  • Davis, D A
  • Zwibel, H S
• Publication Date: 1971-9

Media Info

• Pagination: 57 p.

Subject/Index Terms

• TRT Terms: Amplitude (Physics); Loads; Mooring; Ship motion; Waves
• Uncontrolled Terms: Heaving
• Old TRIS Terms: Heave amplitude; Moored vessels; Regular waves; Ship response; Wave induced loads
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00025626
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NCEL-TN-1183
• Files: TRIS
• Created Date: Feb 11 1972 12:00AM