Safety assessment of a ship swaying under the action of irregular wind and waves

Authors: R.V. Borisov, MA. Kuteynikov, AA. Luzyanin, V.R. Samoylov

Abstract

The nature of roll and wind in the current weather criterion is deterministic. The criterion is either fulfilled or not fulfilled. It does not take into account the possible differences in ship designs and particular qualities of a specific navigation area with the specific wind and waves conditions. It is difficult to correct the weather criterion even using the experimental data. Therefore, the definition of the safety level using the criterion is complicated.
The combined effect of wind and waves is considered in this article taking into account their irregularity. Wherein the spectra of actual wind and waves are used and the mean wind speed is the connecting link between the spectra.
The motion of the vessel is modelled with the help of roll equation in common formulation nonlinear both by damping and by restoring forces. The possibility for a significant simplification of its solution is shown during the study.
The assessment of capsizing probability can be realized by using the analytical formula based on the assumption of Gaussian distribution for roll and Poasson distribution for the occurrence of capsizing.
The proposed stochastic approach renders it possible, in principle, to assess the safety of a particular ship. The accounting for the differences in ship design can be made on the basis of, for instance, capsizing probability or the excess of a critical heel angle.

Keywords: stability normalization, roll motions, irregular waves, seafaring safety, wind and wave loads, probabilistic and deterministic calculation methods.

References

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About authors

Rudolf Borisov - DSc, professor, FSEI State Marine Technical University, 3, Lotsmanskaya st., 190121, St. Petersburg, Russia
rvborisov@mail.ru

Michail Kuteynikov - DSc, FAI "Russian Maritime Register of Shipping", 8, Dvortsovaya Naberezhnaya, 191186, St. Petersburg, Russia
kuteynikov.ma@rs-class.org

Alexander Luzyanin - PhD, associate professor, FSEI State Marine Technical University, 3, Lotsmanskaya st., 190121, St. Petersburg, Russia

Ruslan Samoylov - FAI "Russian Maritime Register of Shipping", 8, Dvortsovaya Naberezhnaya, 191186, St. Petersburg, Russia
samoylov.vr@rs-class.org

Issue: 44/45 (2016)

For citation: R.V. Borisov, MA. Kuteynikov, AA. Luzyanin, V.R. Samoylov. Safety assessment of a ship swaying under the action of irregular wind and waves. Research Bulletin by Russian Maritime Register of Shipping. 2016, No. 44/45, pp. 56-60.

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UDC: 629.12.001.11
Pages: 56-60