Annual General Assembly 2006 - Dalian

Project Session 1

Decision Support For Avoiding Roll
Resonance And Wave Impact For Ship
Operation In Heavy Seas

Knud Benedic, Matthias Kirchhoff, Michael Baldauf

ABSTRACT

There have been several instances of ships being badly damaged due to heavy rolling motion in sea state, which clearly shows the need for a method to estimate the potential danger in order to support the work of the ships' officers. In the paper a simplified but robust method is shown for the on-board calculation, based on the comparison of the ships natural rolling period and the period of wave encounter to prepare a polar diagram for synchronous and parametric resonance and other wave effects from basic data of the ship and the sea state, even by manual calculation. It is also possible to include the potential danger of high wave group encounter or Surf-riding and broaching respectively.
A computer program ARROW-Avoidance of Roll Resonance and Wave impact was developed to display the potential dangerous conditions of rolling resonances or other high wave impacts on ships due to specific wave encounter situations. The tool allows for quick variation of the relevant parameters and was implemented as a module into a ship weather routing program.

Keywords: resonance; parametric rolling; weather routing; surf-riding and broaching

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