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Understanding different aspects of complexity and measuring them properly are important steps of handling ship design complexity effectively. Hie main objective of this article is to develop a practical and comprehensive method to measure ship design complexity, hi engineering design, complexity is measured today by different indexes and methods. This paper initially explores the applicability of such measures in a ship design context supported by a review of different relevant usercases. However, it is acknowledged that most of these measurement methods focus on product-related complexity aspects and rarely address or quantify complexities generated by the design process, the organisation of the film, or the market situation. Therefore, tliis paper introduces a new and comprehensive model to measure ship design complexity including all these aspects. The model quantifies ship design complexity by means of the following nine different descriptive factors: directional, spatial, decision-making, structural, behavioral, contextual, perceptual, temporal, and technological complexity. [ABSTRACT FROM AUTHOR]

The paper examines the intact stability of historic passenger ships from the point of view of the contemporary notion of the intact stability, i.e. the Second Generation Intact Stability Criteria (SGISC) framework. An intact stability assessment using the Vulnerability Level 2 calculation procedures of SGISC for the dead ship condition w as performed on four ocean liners: RMS Titanic, RMS Queen Mary, SS United States and SS Michelangelo, and two cruise ships: MS Song of America and MS Costa Concordia. In addition, the intact stability of the selected ships was appraised using the present-day mandatory intact stability requirements contained in the 2008 Intact Stability Code. The selected ships are believed to be good representatives of the main trends in passenger ship design over a one-hundred-year span bounded by twTo well-known maritime catastrophes: the sinking of the Titanic in 1912 and the Costa Concordia disaster in 2012. The paper offers an insight into how major design changes have affected the intact stability properties of passenger ships over this period. It was found that the examined ocean liners would perform well in terms of intact stability hr the dead ship condition even from the point of view of the SGISC. The analysis also confirmed the advantages of tire approach using the SGISC framework over simplified, (senri)empirical stability assessment methods. By looking into tire evolution of the intact stability of ocean liners and cruise ships from the contemporary perspective, the paper draws the conclusions w hich are considered useful for the design of future passenger ships. [ABSTRACT FROM AUTHOR]

The development of a new methodology for the modeling of the nonlinear responses and stability of ships in stochastic steep waves is presented. The radiation and diffraction hydrodynamic forces are cast in a state-space form by using a panel method followed by the implementation of the estimation of signal parameters via rotational invariance techniques algorithm. Strong free-surface nonlinearities present in the hydrostatic restoring and Froude-Krylov exciting forces are modeled by the fluid impulse theory. The ambient seastate is represented by a state-space diffusion modeled after a given wave spectrum. This enables the study of the nonlinear seakeeping and stability of ships in a seastate by invoking the methods of stochastic calculus. A state-space stochastic differential equation is derived for the states governing the vessel nonlinear responses, and a linear Fokker-Planck partial differential equation is obtained for the joint probability density function of the vessel motions. [ABSTRACT FROM AUTHOR]

This paper studies the robust fuzzy controller design problem for the nonlinear ship fin stabilizing systems. By considering the perturbations, the nonlinear ship fin stabilizing system is represented by the perturbed Takagi–Sugeno fuzzy model. According to the perturbed Takagi–Sugeno fuzzy model, the parallel distributed compensation technique is used to design a model-based robust fuzzy controller. The purpose of the parallel distributed compensation fuzzy controller is to derive linear controllers such that each fuzzy rule of the Takagi–Sugeno fuzzy model can be compensated. In addition to the robust stability performance, the variance constraint and transient performance constraint are also considered in this paper. According to these performance constraints, the linear matrix inequality technique is employed to solve the sufficient conditions developed in this paper. At last, some simulations for the control of nonlinear ship fin stabilizing systems are made to show the usefulness and effectiveness of the proposed design method. [ABSTRACT FROM AUTHOR]

Abstract Bow-flare slamming is issue that must be considered in ship design because it affects the local strength and fatigue life of a ship. In this paper, the experimental study of the spatial distribution of slamming load was conducted, which acts on the bow flares of ultra-large containerships. For a model test, 10,000 TEU container ship model with 1/60-scale ratio divided into six segments was applied. Fifteen force sensors were placed on the bow flare surface to measure slamming load. The slamming loads were measured in regular and irregular waves at various ship speeds, wave lengths, wave heights, and heading angles. In a regular wave test, the slamming load was larger in oblique sea than in head sea because the relative angle of the wave and bow flare is smaller in oblique sea. In an irregular wave test, extremely large slamming loads were measured at the centre line at the bow, which is influenced by the horizontal relative velocity such as the ship speed and surge. In an analysis of the slamming load of the ship, the direction of wave and forward speed of the ship should be carefully considered. These are difficult to consider in 2D analysis. Highlights • The measured slamming impact loads on the bow flare of ultra-large containership are presented. • Various ship speeds, heading angles, wave heights, and wave lengths were applied in regular and irregular waves. • It is known that the slamming load of the ship is mainly determined by the vertical relative velocity, but it was found that abnormal large slamming load occurs due to horizontal relative velocity as well as the vertical relative velocity in the model test of irregular wave. • The slamming load in oblique sea can be larger than that in head sea because the relative angle between the bow the wave surface decreases in oblique sea. [ABSTRACT FROM AUTHOR]

Based on the designed anti-capsizing airbag of passenger ship sailing inland-river, this paper presents the anti-capsizing airbag devices, its principles, and the studies on the safety volume of anti-capsizing airbag; furthermore, the influences of anticapsizing airbag on the ship stability are analyzed. The results indicate that the anti-capsizing airbag improves the ship stability and the ship safety. [ABSTRACT FROM AUTHOR]

The VAWT (vertical axis wind turbine) has advantages in the development of large-scale offshore wind power. This paper presents a motion study of a 5 MW floating VAWT composed of the Φ type Darrieus wind turbine and the spar type floating foundation with heave plates. A computing code of aerodynamic loads was developed considering the dynamic stall and the floating foundation motions. The motion equations of the floating VAWT were established and solved numerically. Model tests were conducted, and the results of heave and pitch motion in test were compared with that of numerical calculation. The PRAOs (pseudo response amplitude operators) of numerical calculation are found to agree well with the experimental data with wave only conditions, and have some little discrepancies with wave and wind conditions. The surge-heave-pitch motions of the floating VAWT were analyzed. The results show that the aerodynamic forces have minimal influence on the heave motions of the floating VAWT, while they obviously increase the mean values of surge and pitch motions. The surge, heave and pitch frequencies of the floating VAWT are dominated by the wave frequencies, and the 2P (twice-per-revolution) response of pitch motions is not significant. [ABSTRACT FROM AUTHOR]

Parametric roll of ship is a rare event occurring in specific conditions, but it can cause the dynamic roll instability. Since this phenomenon is dependent on ship speed and wave frequency, the development of roll motion and the resultant added resistance which can cause speed change should be considered simultaneously when parametric roll occurs. This paper considers a numerical study on the added resistance of a modern containership under parametric roll. A time-domain Rankine panel method adopting a weakly nonlinear formulation is adopted to obtain ship motions and added resistances in waves. Seakeeping computations in regular head-sea conditions are performed with and without parametric roll, and the increment of added resistance is investigated with regard to the components classified in the direct pressure integration method. Furthermore, according to the decoupling phenomena between the components of the vertical motions and the roll motion, a correlation between the parametric roll and the added resistance is derived. Lastly, a simple prediction method for the added resistance in irregular parametric roll motion is suggested based on the correlation, and its accuracy and efficiency are discussed by comparing the prediction with the results of the direct numerical computation. [ABSTRACT FROM AUTHOR]

Liquefaction of mineral ores, such as iron ore and nickel ore fines, resulting in cargo liquefaction and hence displacement (‘cargo shift’) leading to loss of ship stability, has been a major cause of marine casualties. In the paper, rolling response in regular waves for a 2D rectangular hold, partially filled with moist bulk cargo is investigated, by applying a simulation approach based on an adapter that couples a CFD code and a DEM (‘Discrete Element Method’) code. A parametric investigation is undertaken to identify the key parameters that trigger cargo and ship instabilities. [ABSTRACT FROM AUTHOR]

A series of analyses are carried out to predict the structural crashworthiness of a ship during a collision. The numerical configuration is verified by structural simulations based on a laboratory experiment wherein a penetration test is considered as the experimental reference. Comparative observations of structural behaviour are carefully conducted to ensure the reliability of the present method for conducting large-scale collisions. At this stage, the proper procedure and configuration for structural calculations subject to accidental loads are determined. The second stage addresses the calculations for various side collision scenarios. The simulations consider a double hull Ro-Ro passenger ship being struck at various locations, and the overall behaviour of the side hull along the longitudinal axis is observed. The main study considers the target location and striking speed to obtain adequate data related to crashworthiness criteria, i.e. the internal energy and extent of damage. Finally, the criteria of various scenarios are summarized. Further calculations comparing the results with a safety factor are presented together with a consideration of structural behaviour to estimate the safety limit within the confines of strait territory. [ABSTRACT FROM AUTHOR]

The paper presents computational stability issues with a flooded ship compartment situated on boat deck. As the main criteria for stability of the warship, calculation algorithm of metacentric height and righting levers have been defined, with a free surface effect taken into account. Based on the results of the calculations presented in tabular and graphical forms, suitable conclusions have been drawn up. [ABSTRACT FROM AUTHOR]

Significant reduction of steady-state resistance of a di-hull system with certain hull configurations (relative stagger and separation between the hulls) occurs because of interference effects between the two sets of ship-generated waves. The far-field wave interference and the resulting wave-resistance reduction of an asymmetric di-hull system, consisting of two distinct Series 60 hull models with various hull configurations are studied. The initial search for optimal configurations of the maximum prospective resistance reduction is conducted by an existing di-hull thin-ship computation. These theoretical results are then compared to the ones acquired by towing-tank measurements and those given by a semi-experimental approach. The latter approach obtains the wave resistance by combining experimental “wave-cut” data and analytical expressions developed for such a di-hull system. Experimental uncertainties are briefly discussed. Results of this study show that a considerable amount of wave-resistance reduction is indeed possible for the investigated hull configurations. However, beyond the far-field interference of the waves, near-field interactions of the two hulls are found to have non-negligible influence on the total resistance performance of the di-hull system. [ABSTRACT FROM AUTHOR]

An average of 12 polar lows develop yearly in the Norwegian and Barents Seas, when unstable air is accumulating over the ice-open water interphase. Polar lows are intense and rapid, accompanied by high wind speeds, large wave growth, and large snowfalls. There are uncertainties in polar low forecasts, and marine activities should not take place along the possible tracks of such events, even if thewaveswould be less than the extreme waves for the area. The metocean (meteorology and oceanography) conditions in polar lows suggest that a vessel at sea may experience severe sea spray icing. In this paper, we present vessel stability concerns, and the effect of snow and ice loads on stability, in polar low situations. Stability analysis results show that the additional snow and ice loads have more influence on smaller vessels' stability compared to larger vessels. [ABSTRACT FROM AUTHOR]