Development of a Ship Weather Routing System

On unstable ship motions resulting from strong non-linear coupling

An Introduction to Parametric Resonance.- Part I Detection and Estimation of Parametric Resonance: Detection of Parametric Roll for Ships.- Estimation of Parametric Roll in Random Seaways.- Part II Parametric Roll: Trimaran Vessels and Parametric Roll.- Probability of Parametric Roll in Random Seaways.- Domains of Parametric Roll Amplification for Different Hull Forms.- Probabilistic Properties of Parametric Roll.- Experience from Parametric Rolling of Ships.- Ship Model for Parametric Roll Incorporating the Effects of Time-Varying Speed.- Part III Control of Parametric Resonance in Ships: Frequency Detuning Control by Doppler Shift.- Optimal Speed and Heading Control for Stabilization of Parametric Oscillations in Ships.- A U-Tank Control System for Ships in Parametric Roll Resonance.- Part IV Control of Parametric Resonance in Mechanical Systems: Parametric and Direct Resonances in a Base-Excited Beam Carrying a Top Mass.- A Study of the Onset and Stabilization of Parametric Roll by using an Electro-Mechanical Device.- Controlling Parametric Resonance: Induction and Stabilization of Unstable Motions.

Parametric resonance in dynamical systems

https://backend.orbit.dtu.dk/ws/files/7727815/2011_ARC_Perez_Blanke.pdf

Ship Roll Damping Control

The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems together with the challenges associated with their design. It discusses the assessment of performance and the applicability of different mathematical models, and it surveys the control methods that have been implemented and validated with full scale experiments. The paper also presents an outlook on what are believed to be potential areas of research within this topic.

Ship roll damping control

In October 1998 a post-Panamax C11 class containership encountered extreme weather and sustained extensive loss and damage to deck stowed containers. The motions of the vessel during this storm event were investigated through a series of model tests and numerical analyses that confirmed the vessel's parametric rolling response in head seas at the time of the casualty. These studies provide insight into the conditions in which post-Panamax containerships are likely to experience head sea parametric rolling, and the magnitude of motions and accelerations that can occur. The findings from this investigation are presented in this paper, together with discussion of how such extreme motions impact the design and application of container securing systems. Also outlined in the paper are recommendations for additional research needed to better understand the influence of vessel design and operational considerations on the propensity of post-Panamax containerships towards parametric rolling. This investigation and other recent studies demonstrate that parametric roll in extreme head or near head seas can occur when unfavorable tuning is combined with low roll damping (reduced speed) and large stability variations (governed by wavelength, wave height, general hull form, bow flare, and stern shapes). Parametric rolling is an unstable phenomenon, which can quickly generate large roll angles that are coupled with significant pitch motions. The rolling occurs in phase with pitch, and on containerships introduces high loads into the containers and their securing systems. It appears that post-Panamax containerships may be particularly prone to this behavior. This is an important issue considering the large number of these vessels scheduled for delivery in the next few years.

An investigation of head-sea parametric rolling and its influence on container lashing systems

Recent studies have demonstrated that parametric roll in extreme head or near head seas can occur when unfavorable tuning is combined with low roll damping (reduced speed) and large stability variations (governed by wavelength, wave height, general hull form, bow flare, and stern shapes). Parametric rolling is an unstable phenomenon, which can quickly generate large roll angles that are coupled with significant pitch motions. The rolling occurs in phase with pitch, and on containership s introduces high loads into the containers and their securing systems. It appears that post-Panamax containerships may be particularly prone to this behavior. This is an important issue considering the large number of these vessels scheduled for delivery in the next few years. In October, 1998, a post-Panamax, C11 class containership encountered extreme weather and sustained extensive loss and damage to deck stowed containers. The motions of the vessel during this storm event were investigated through a series of model tests and numerical analyses. These studies provide insight into the conditions in which post-Panamax containerships are likely to experience head sea parametric rolling, and the magnitude of motions and accelerations that can occur. The findings from this investigation are presented in this paper, together with discussion of how such extreme motions impact the design and application of container securing systems. Also outlined in the paper are recommendations for additional research needed to better understand the influence of vessel design and operational considerations on the propensity of post-Panamax containerships towards parametric rolling.

https://www.steamshipmutual.com/ParametricRoll.pdf

J. Randolph Paulling

Papers

An investigation of head-sea parametric rolling and its influence on container lashing systems

An Investigation of Head-Sea Parametric Rolling and its Influence on Container Lashing Systems