International Shipbuilding Progress - Volume 51, issue 2-3

Authors: Papanikolaou, A. | Spanos, D. | Boulougouris, E. | Eliopoulou, E. | Alissafaki, A.

Article Type: Research Article

Abstract: The main findings of the investigation into the sinking of the passenger/Ro-Ro ferry Express Samina and specifically the ship's damage stability behaviour are outlined in this paper. In the framework of this investigation, the flooding and sinking of the ship following damage was simulated by use of NTUA-SDL's time domain simulation method and the results could be confirmed by analysis of available testimonies of survivors. Progressive flooding through open left watertight doors was found to be …the main reason for ship's sinking. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 95-120, 2004

Authors: Matsuda, Akihiko | Hashimoto, Hirotada | Umeda, Naoya

Article Type: Research Article

Abstract: Recent model experiments by the authors indicated that bow-diving is one of the crucial capsizing modes for a ship traveling in following and quartering seas with high forward velocity, while only a few research attempts on this phenomenon have been reported so far [1]. In this paper, basic features of bow-diving are discussed with measured time series. It is concluded that bow-diving is associated with surfriding and triggered with submergence of bow bulwark top. Static calculating …of vertical distance between bulwark top and wave surface by Froude-Krylov assumption well explained the possibility of bow-diving. Once the bow submerged, the restoring arm can be drastically reduced and then the ship could capsize. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 121-133, 2004

Authors: Clauss, Günther F. | Hennig, Janou

Article Type: Research Article

Abstract: Encountering a freak wave remains one of the most horrible visions for a ship master. Until now the mechanisms which underlie large rolling and subsequent capsizing due to a rogue wave are only partly disclosed. In the framework of the German research project ROLL-S which is funded by the German Federal Ministry of Research and Education (BMBF) nine partners are cooperating on the investigation of large rolling and capsizing mechanisms covering .elds like numerical analysis and simulation, validation, …and evaluation of capsizing risk. The project part presented here deals with the validation of numerical tools for the analysis of large rolling and capsizing. The main goal is the implementation of a sophisticated capsizing test procedure. For providing useful data for the analysis of the capsizing process as well as for the validation of numerical methods, exact correlation of wave excitation and ship rolling is indispensable. All wave trains are tailored for the speci.c purpose of each capsizing test and generated in the model tank. Unusual wave trains like regular waves followed by a freak wave and special wave groups within a de.ned random sea as well as realistic wave scenarios have been generated. The parameters of the model seas are systematically varied to investigate the ship model response with regard to metacentric height, model velocity, and course angle for different ship types. The wave elevation at the position of the ship model in time and space is calculated (and controlled by registrations during model tests) in order to relate wave excitation to the resulting roll motion. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 135-155, 2004

Authors: Lopatoukhin, Leonid J. | Boukhanovsky, Alexander V.

Article Type: Research Article

Abstract: The problem of extreme wave estimation is crucial at last 25–30 years due to active using of ocean resources. Mainly the attention paid to estimation of extreme waves in the fixed spatial point of the sea. But for ship navigations, transport operations, offshore supplying etc. estimates of the spatial occurrences of extreme waves are required. In these cases spatiotemporal variability of wave fields is of special interest. One of the most interesting extreme phenomena is freak (or rogue) …waves. These one are anomaly steep and high waves. The probability of freak waves generation depends from a lot of internal (modulation, nonlinearities, etc.) and external (metocean) factors. Spatial dimensions of the sea region increase the probability of ship encounter with a freak wave. Classical statistical analysis of time series do not allows estimating the probabilities of freak waves occurrence and associated weather conditions. Main definitions of freak waves, reasons of appearance, possibility of generation in the sea and approach to estimation is presented. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 157-171, 2004

Authors: Bulian, Gabriele | Francescutto, Alberto | Lugni, Claudio

Article Type: Research Article

Abstract: This paper summarizes the results and the problems still open regarding the development of a 1.5DOF nonlinear mathematical model of the parametric rolling in longitudinal waves with particular regard to the head sea condition. A first part is devoted to the case of regular waves, while the second concerns parametric rolling generated by irregular waves obtained by means of white noise filtered through a linear filter with adjustable bandwidth and by using a Bretschneider spectrum. The …availability of an extensive series of test results on scale models conducted at University of Trieste and at INSEAN, allows a thorough discussion of the problems connected with the threshold formulation for parametric rolling and its amplitude modelling above threshold. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 173-203, 2004

Authors: Umeda, Naoya | Hashimoto, Hirotada | Vassalos, Dracos | Urano, Shinichi | Okou, Kenji

Article Type: Research Article

Abstract: This paper describes latest collaborative researches between Japan and the UK on parametric roll resonance of a container ship in following and head seas with realistic modelling of restoring moment as a nonlinear function of wave steepness in experimental, geometrical and analytical approaches. Firstly, captive model experiments were conducted, and demonstrated that the Froude-Krylov prediction could overestimate the amplitude of its variation. Secondly, Poincaré mapping technique applied to the numerical model with …measured time-varying restoring moment was used for tracing stable steady states, and revealed symmetry-breaking, period-doubling, chaos and capsizing associated with parametric roll resonance. Thirdly, an averaging method was applied to the same numerical model, and confirmed good agreement with the Poincar?mapping as well as subcritical bifurcation. Finally, by utilising the present numerical model and methodology, it is shown that a requirement of higher metacentric height does not always improve safety for capsizing associated with parametric roll resonance. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 205-220, 2004

Authors: Francescutto, Alberto | Naito, Shigeru

Article Type: Research Article

Abstract: The problem of large amplitude, nonlinear, rolling in the presence of a stochastic beam sea has been approached several times in the past. However, most of the published work is devoted to the consideration of the case where the bandwidth of the excitation (input process) is greater than that of the rolling ship (output process). As a result the complex nonlinear roll dynamics cannot exhibit all its typical peculiarities and in particular no consideration is given …to the very dangerous possibility of bifurcations and jumps of amplitude as precursors of an eventual degeneration to chaotic behaviour. This possibility was proposed long ago in the narrow band stochastic case and successively revealed experimentally in regular beam waves. In the meantime the possibility of bifurcations in the presence of stochastic excitation was confirmed together with the validity of Gaussian methods to this purpose. In this paper, the hypothesis of "artificial" narrow band sea spectrum is abandoned and the case of Pierson-Moskowitz case is analysed by means of the cumulant-neglect closure method. The strong effect of non linearities is highlighted together with the possibility of complex roll dynamics. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 221-235, 2004

Authors: Ali, Baharuddin | Katayama, Toru | Ikeda, Yoshiho

Article Type: Research Article

Abstract: In the present study, the prediction method of viscous roll damping proposed by Ikeda et al. is modified for applying to a special vessel with round hull form and a long and wide bar keel (deadwood). The modified method is applied to a typical Indonesian fishing vessel, and the prediction results by the method are confirmed to be in fairly good agreement with experimental results. Effects of bilge keels on roll damping of such a vessel are also …examined by the prediction method and experiments. Roll motion of such a vessel in regular beam waves is measured to find that strip methods using the modified roll damping prediction method give good results of roll responses in moderate waves but significantly overestimate the roll responses in heavy waves. It is experimentally confirmed that rapid drift motion in heavy waves increases the roll damping and decrease wave exciting roll moment in heavy seas, and that these phenomena causes the discrepancy of roll responses in heavy seas. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 237-250, 2004

Authors: Vassalos, Dracos | Jasionowski, Andrzej | Cichowicz, Jakub

Article Type: Research Article

Abstract: Following the reopening of the Intact Stability Code by the International Maritime Organisation (IMO), a number of questions are being raised concerning the practical applicability of Resolution A.562 known as the Weather Criterion on modern passenger ships and answers sought on a way forward by way of either re-examining and suitably tuning the criterion to reflect current (and emerging) ship particulars or adopting emerging approaches/philosophies to assessing ship safety, using firstprinciples performance …assessment tools. This paper attempts to provide pertinent answers to these questions. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 251-271, 2004

Authors: Letizia, Luca | Vassalos, Dracos | Jasionowski, Andrzej

Article Type: Research Article

Abstract: This paper aims to clarify a number of issues concerning the dynamics of a damaged ship, interpreting the results of recent towing tank tests by means of a simplified linear model with two degrees of freedom. In this sense, this work can be seen as the natural evolution of the extensive body of work in this field undertaken by the SSRC during a long series of large research projects, including the Joint North West European Project [2], the MCA …funded Time Based Survival Criteria of Passenger Ro-Ro Vessels, Phase 1 and 2 [3] and, above all, the Fifth EC Framework RTD projects HARDER and NEREUS [1], during which the experimental evidence presented in this paper was collected. Show more

Citation: International Shipbuilding Progress, vol. 51, no. 2-3, pp. 273-291, 2004