An integrated methodology for the design of Ro-Ro passenger ships

The present paper provides a brief introduction to the holistic approach to ship design, defines the generic ship design optimization problem and demonstrates its solution by use of advanced optimization techniques

Stability upgrade of a typical Philippine ferry

The waterborne transport in the Philippines has been a sensitive subject amplified by the lack of rules and regulations to restrict ship-owners profit-driven decisions, leading to overloading, with significant impact on ship stability. Most of the Tier-II vessels are using solid ballast to balance trim and increase static stability at the expense of freeboard. To improve matters whilst facilitating the currently adopted process, solutions are required that offer additional buoyancy with increased stability. To this end, a solution is proposed here through the addition of sponsons, providing the required level of intact stability and residual floatability/stability, using a typical Ro-Pax. In this paper, a case study is presented to demonstrate the validity of the proposed solution

An alternative system for damage stability enhancement

There is an ongoing and continuous initiative to improve the survivability of passenger vessels and in the past increasing safety standards have generally been catered for through the use of design(passive) measures. However, this approach is becoming saturated and any such measures to improve damage stability severly erode ship earning potential and are being resisted by industry. In a change of direction, this paper aims to explore the use of operational(active) measures for damage stability enhancement in line with IMO Circular 1455 on equivalents. An alternative system for damage stability enhancement is intorduced that involves injecting highly expandable foam in the compartment(s) undergoing flooding during the initial post-accident flooding phase thus enhancing damage stability and survivability of RoPax vessels well beyond the design levels in the most cost-effective way currently available. This is a mind-set changing innovation that is likely to revolutionise design and operation of most ship types and RoPax, in particular. A case study has been performed on a large RoPax vessel with impressive results that will challenge the current established practice and open possibilities for novel and innovative design configuration

A study on the effects of bilge keels on roll damping coefficient

A study of the roll damping of a two-dimensional FPSO model produced by bilge keels using CFD method is presented in this paper. The tool to be utilized is the well-known code Star-CCM+, which uses the Volume of Fluid (VOF) approach to capture the free surface. The results are validated by comparison with experiments. Using the results from a number of simulations, the roll damping coefficient resulting from locating the bilge keels at different positions will be calculated. The analysis of the rolling damping coefficients for the different locations will provide a useful design tool for optimising the roll damping of vessels with bilge keels

Quantification of the maritime security problem onboard passenger ship

Given the large number of recent terror attacks worldwide, there is a growing concern over the security issue in the maritime world. Aim of this paper is to address a scenario pertinent to the maritime security problem using the evacuation simulation software tool EVI. The vessel chosen for this case study is a 13-deck cruise ship. The scenario investigated deals with the evacuation of a large density populated area within the vessel, where an explosive device has been placed and assesses the potential loss of life, according to the distance of the agents relative to the explosion blast. Three different positions of the explosive device are examined in this study and for each position six different cases are examined, in which the effect of prior warning to the explosion is taken into consideration. In the first case, the explosion takes place at the beginning of the simulation (t=0) in order to replicate such a scenario in which those agents within the restaurant are un-alerted to the presence of the explosive device. In the rest of the cases the explosion takes place after warning times of 0.5, 1, 1.5, 2 and 2.5 minutes respectively in order to assess the sensitivity of the fatality rate and evacuation to prior warning time

Prevention of parametric rolling through multi-objective optimisation

IMO is developing new intact stability criteria which include parametric rolling and they will have an impact on some ship types. A benchmark study of those criteria on C11 containership is presented herein. Moreover, the authors use them as an objective for the design optimisation which is solved using Genetic Algorithms

Goal setting of EEOI for chemical tankers by Monte Carlo simulation

In accordance with the current regulations, the companies have to investigate the suitability of the applied operational measures; to assess the available solutions for the energy efficiency improvement of their fleet; and produce more suitable operational measures or revise their already applied measures. For this purpose, there is need to have a SEEMP and achieve EEOI targets. In this paper, a method for the prediction of the annual performance of the energy efficiency for a company’s fleet, based on Monte Carlo Simulation will be presented. As a case study, the method will be applied on a chemical tanker fleet. Recorded voyage data, including EEOI values, cargo type and quantity, mileage covered, speed profiles, fuel types etc., will be used. Conclusions on the feasibility, usability, reliability as well as suggestions for further development of the method will be included

Numerical assessment of cargo liquefaction potential

Liquefaction of fine particle cargoes, resulting in cargo shift and loss of stability of ships, has caused the loss of many lives in marine casualties over the recent past years. Since the dangers of cargo liquefaction have long been known to the shipping industry, the question of why the phenomenon is resurfacing now would be a legitimate one. With this in mind, an UBC3D-PLM model based on FEM theory in the commercial software PLAXIS is presented in this paper as a means to consider soil DSS (Direct Simple Shear) test to verify the model and a method is presented to assess cargo liquefaction potential. Shaking table tests with different amplitude, frequency and initial degree of saturation of cargoes are studied to predict time-domain characteristics. The proposed method could be used as a reference in support of a suitable regulatory framework to address liquefaction and its effect on ship stability

Parametric design and holistic optimisation of post-panamax containerships

The fluctuation of fuel price levels, along with the continuous endeavour of the shipping industry for economic growth and profits has led the shipbuilding industry to explore new designs for various types of merchant ships. Moreover, the introduction of new regulations by the IMO has added further constraints to the ship design process. In this respect, proper use of modern CAD/CAE systems extends the design space, while generating competitive designs in short lead time. This study deals with the parametric design and holistic optimisation of a post-panamax containership. The methodology includes a complete parametric model of a containership’s external and internal geometry, as well as the development and coding of all tools required for the determination of both the design constraints and the efficiency indicators, which are used for evaluating the parametrically generated designs. The second-generation intact stability criteria are taken into consideration in the optimisation process. The set-up multi-objective optimisation problem is solved by use of the genetic algorithms and clear Pareto fronts are generated