LONG-TERM INVESTIGATIONS INTO SHIP HULL REACTIONS IN A NATURAL SEAWAY,

If the forces acting on a ship at sea are recorded they will vary irregularly with time, and can be analysed only by use of probability theory. Over a short time span the system characteristics will be found not to vary with time (i.e. will be stationary), so that an average value or a standard deviation will describe the process fully. The basis for the numerical investigations is provided by the hydrodynamic calculations for the forced vibration of a ship in regular waves. The hull reactions resulting from this enable characteristics to be derived for short-term stationary irregular loadings. A mathematical model for long-term reactions is derived which is based on the assumption that the natural seaway over the long term can be regarded as the sum of stationary short-term processes, and that the probability of the short-term processes occurring during the service life of the ship can be predicted at the design stage from frequency statistics for the sea areas involved. This model enables design values for the forces acting on the ship to be determined. Comparisons between different designs will quickly indicate qualitative differences, although at present there is insufficient data available to place absolute values on the results.

• Supplemental Notes:
  • Schiffbauforschung, 24 (1985), p. 207 (No. 4) [5 pp., 3 ref., 8 fig., 2 tab.]
• Authors:
  • Linnert, M
• Publication Date: 1985

Language

• German

Subject/Index Terms

• Subject Areas: Marine Transportation;

Filing Info

• Accession Number: 00689469
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM