SHIP CAPSIZE RISK IN A SEAWAY USING TIME DOMAIN SIMULATIONS AND FITTED GUMBEL DISTRIBUTIONS

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Authors
  1. McTaggart, K.A.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
Risk analysis provides the most rational approach for designing and operating a ship to prevent capsize. A capsize risk analysis procedure must adequately consider the dynamics of ship capsize in waves. This paper presents an efficient method for determining capsize risk for a given seaway and ship operational condition using time domain simulations. The risk of capsize during one hour exposure to a given seaway is dependent on the wave process realization, which is determined by a seed number and resulting random wave phases. The dependence of maximum roll angle on wave process is modelled by fitting a Gumbel distribution to maximum roll angles from a moderate number of simulations. Sample computations for a naval frigate demonstrate that a Gumbel distribution provides a very good fit to maximum roll angles from different wave realizations. The sample computations provide guidance regarding the number of wave realizations and simulation durations that should be used for fitting Gumbel distributions.
Keywords
Time domain;Capsizing;Dynamic stability;Computer programs (FREDYN)
Date of publication
01 Jul 1998
Number of Pages
9
DSTKIM No
99-00269
CANDIS No
510200
Format(s):
Hardcopy;Document Image stored on Optical Disk

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