Excessive roll motions of a ship in a severe sea may lead to capsizing. It is inappropriate to treat such a process as stationary, and more satisfactory to consider the probability that the roll motion stays within defined amplitude limits for a specified period of time. This so-called "first-passage probability" is closely related to the mean first-passage time: the time taken, on average, for the roll amplitude to reach a prescribed critical level from given initial conditions. A theoretical expression for the first-passage time is evaluated using a range of typical values of the input parameters, and results are compared with those of numerical simulation. These comparisons show that the theory gives good estimates of the first-passage time provided that the frequency bandwidth of the response is narrow compared with that of the forcing, and that the theory is in all cases conservative. The theory should therefore be useful for design purposes.

  • Supplemental Notes:
    • Report
  • Corporate Authors:

    University of Sussex School of Engineering and Applied Sciences

    ,   England 

    NMI Ltd., Feltham

    Middlesex,   England 
  • Authors:
    • Roberts, J B
  • Publication Date: 1983-9

Media Info

  • Features: References;
  • Pagination: 46 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00661044
  • Record Type: Publication
  • Source Agency: Maritime Technical Information Facility
  • Report/Paper Numbers: NMI-172
  • Files: TRIS
  • Created Date: Jul 21 1994 12:00AM