Large cruise ships can carry 10 000 persons onboard, and consequently, survivability of the ship in the event of a flooding accident is essential. Many designers are already conducting advanced damage stability analyses beyond the regulatory requirements. With increased computing capacity, survivability analyses, by using time-domain simulation tools, are already commonly applied in the design of new cruise ships. Consequently, it is essential that such tools are properly validated, in terms of ship response and detailed flooding behavior, to assess the capability and applicability of the tools. For this purpose, an international benchmark study on simulation of flooding and motions of damaged cruise ships was conducted within the EU Horizon 2020 project FLARE, using experimental data from new dedicated model tests as a reference. The test cases include transient and progressive flooding, both in calm water and in irregular beam seas. The results indicate that capsize is properly captured by simulation codes, but there are notable differences in the flooding progression and capsize mechanisms, especially when flooding takes place in high waves.

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The need for decision support after a flooding casualty requires the development of fast and accurate progressive flooding simulation procedures. Here, a new quasi-static technique is presented, proposing a differential algebraic formulation capable to consider independently the flooding process in the internal rooms. The proposed method is efficient while simulating long flooding chains along rooms connected by similar size openings, a condition that likely occurs on large passenger ships. Moreover, the computational performances of the simulation procedure have been enhanced by adapting the time step to the progressive flooding pace. The adoption of an adaptive time step algorithm reduces significantly the calculation time. The novel procedure has been tested on the recommended benchmark cases for flooding simulations, highlighting the accuracy and flexibility of the proposed method.

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During a flooding emergency, the master has to take hard decisions with serious impact on passengers and crew safety. A fast and reliable time domain simulation of the progressive flooding process can significantly aid the master in choosing the right counteractions immediately after the damage occurrence. In last decades many methods to simulate progressive flooding have been developed with increasing precision, but most of them require too much computational effort being not suitable for a direct onboard application. This paper presents a novel quasi-static simulation technique capable to provide accurate results in a reasonable calculation time. The analytical solution of the linearised system of governing differential equations allows to extend the time step over the intrinsic limits of numerical integration methods without affecting accuracy. The approach has been compared with numerical integration of non-linear system of equations and a recent pressure correction technique on a box-barge test case available in the literature.

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The continuous increasing attention to environmental sustainability and air pollution reduction for transport systems, requires not only to adopt new technologies and innovative solutions to limit vehicles emissions, but also to study their life-cycle. In case of inland navigation, the operation close to urban areas or in natural protected environments requires the adoption of a green propulsion. Moreover, especially for small crafts, the problem of ship disposal at the end of life is of high importance, even once plastic materials should be disposed, due to high costs and process complexities. For such a reason the design of a new generation green passenger craft requires the analysis and knowledge of multiple engineering fields, that could lead to a fast and successful design only by means of an integrated approach. In the present work, this approach will be applied to the design of a passenger craft, adopting an hybrid electric powering system and build with strip planking process for wooden ships. The description of the construction process will be here described together with the on-board electric power system. The integrated approach allowed also to directly evaluate the vessel operative profile and asses whether the vessel could perform a Zero Emission Mode navigation.

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The analysis of time records, coming from seakeeping experiments in irregular waves, is used to determine the occurrence of extreme events. The common procedure used for data analysis is to assume that the statistics of record’s peaks is following two or three parameters Weibull distribution. For particularly severe sea states, it can happen that the peaks assume a multi-modal distribution and the use of a Weibull distribution may lead to errors in the extreme value estimate. It is than possible to use multi-modal distributions, or to change the peaks extraction technique, adopting a certain threshold. Here, the determination of extreme values probability distribution parameters by genetic algorithm is applied to improve the methodology of extreme sea state prediction. A data analysis procedure is here proposed and tested on a time record coming from seakeeping model-scale experiments and on a set of wave heights record, in comparison with standard Weibull approach.

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For the dimensioning of particular structures like stingers or generic tubular elements for offshore industry, it is usual to predict the extreme values of wave induced loads. Both for model test and calculations, the traditionally adopted methods of analysis are based on Weibull distribution. The necessity to investigate severe sea state conditions together with the increased complexity of the structure is an evident source of non-linearities in the exciting force peaks distribution. In the specific, the adoption of a standard Weibull approach is not indicated for accurately predict the extreme loads. The adoption of more accurate distributions suitable to capture peaks non-linearity will ensure to overcome or capture possible multi-modal behaviour of the considered population. These enhanced techniques can be used not only for model test results analysis, but also for results coming from preliminary hydrodynamic calculations (CFD). In the present work, two different methodologies based on Mixed Weibull and Generalised Pareto distributions will be applied to the results obtained for a stinger geometry, where Morison theory is adopted to evaluate wave loads considering shield effects between the single tubular elements.

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For the natural gas transportation, several technologies can be applied, having different effectiveness and costs depending on the analysed case. The Mediterranean Sea is presenting a typical scenario where compressed natural gas (CNG) transportation is particularly attractive compared to liquefied natural gas (LNG) and pipelines, not only for stranded gas shipping but also for transportations cases where CNG is usually representing the most economically convenient solution. Approaching the design of a CNG ship is not an easy task, since the pressure vessel (PV) technology is strongly influencing the ship layout and hull form. Here an enhanced conceptual design method is adopted; taking into account the economic-financial issues together with logistics, in order to determine the best fleet composition selecting the best ships for the selected scenario. The ships composing the fleet are supposed to load/offload the natural gas on buoys; hence, dynamic positioning (DP) will also be considered as an attribute in the evaluation of alternative designs. As final outcome of the enhanced concept design process it will be possible to speed up drawing of the preliminary lines plan and general arrangement plan of the sister ships composing the fleet.

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To face the design of a new ship concept, the evaluation of multiple feasible solutions concerning several aspects of naval architecture and marine engineering is necessary. Compressed natural gas technologies are in continuous development; therefore, there are no available databases for existing ships to use as a basis for the design process of a new unit. In this sense, the adoption of a modern multi-attribute decision-based method can help the designer for the study of a completely new ship prototype. A database of compressed natural gas ships was generated starting from a baseline hull, varying six hull-form parameters by means of the design of experiment technique. Between the attributes involved in the concept design process, stability is for sure one of the most relevant topics, both for intact and damaged cases. This work describes two approaches to identify the compliance of a ship with the intact stability regulations based on the ship main geometrical quantities. Moreover, a metamodel based on the maximum floodable length concept (damage stability) allows determining the main internal subdivision of the ship. The metamodel outcomes were compared with results from direct calculations on a ship external to the database, highlighting the adequate accuracy given by the developed methods.

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Nowadays, fuel consumption reduction is a primary concern in order to minimize operative costs and emissions during navigation. On this purpose, ballast management play an important role, in order to find the best configuration for ship navigation. An optimal ballast water distribution ensures to find a floating position having the minimum fuel consumption while assuring the fulfillment of rules requirements related to strength and stability. Since ships are operating also in adverse sea state condition, optimal ballast conditions should be found also for service conditions, considering the impact of added resistance due to waves on the propeller and consequently to fuel consumption. Within an emergency decision support system, an optimum ballast system has been developed satisfying the above mentioned requirements. In order to assess the optimal ballast allocation in a fast and accurate way, the equations are linearized and solved by means of pseudo inverse matrix. The target of this process is to find for a defined set of ballast tanks the level, or rather the volume, of water to reach the optimum floating position. The procedure has been tested on a reference ship and the results are here reported and described.

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To manage the overall design process of complex systems like ships, particular attention has to be deserved to the connections and overlapping between the design stages. Therefore, the paper addresses the complex aspect of quickly moving from concept to preliminary design, so yielding an initial design in a decreasing time span. Concept design is here treated as a MADM synthesis process, where a huge number of feasible designs are randomly generated by an adaptive Monte Carlo sampling and ships’ properties are assigned by means of metamodeling techniques. Non-dominated solutions are then filtered as a Pareto set identifying a short list of preferred solutions up to the “best possible” design characterized by top-level specifications (geometry, ship performance, capex, opex, etc.). This procedure has its core in the trade-off between technical and economic attributes also embracing uncertainty in a ship’s lifetime perspective. A set of ship parameters are oriented to preliminary hull geometry and general arrangement definition. Hierarchical dependencies are used to match the concept hull form with modular internal spaces. The process is here applied to a case study, consisting in the initial design of a Compressed Natural Gas (CNG) ship as member of a fleet optimised for gas shipping from the Zohr field (Egypt) to the Adriatic Sea.@en

The compressed natural gas (CNG) transport is becoming nowadays an attractive solution not only for stranded gas shipping where current technologies like liquefied natural gas (LNG) and pipelines are not economically competitive, but also for long-enough distance transport of large volumes of natural gas, where LNG still represents the most economical solution. In fact, recent studies on pressure vessels (PV) materials allow to significantly reduce the ship displacement in case of PVs Type 3 and Type 4 when compared to existing prototype designs with PVs Type 1 and Type 2, also leading to completely different hull forms. Since CNG ship design is a new research field for Naval Architecture, the concept design phase assumes an utmost importance with respect to design of well-known ship types, not only for the main parameters determination and performances assessment, but also for the study of completely different solutions for some subsystems. To this purpose, the present paper presents a technical-economic comparison between two different kinds of propulsion systems: conventional diesel drive propulsion with propellers and a complete diesel electric solution with pods. The differences between the two solutions are influencing both internal layout and ship dimensions, leading to two completely different ship concepts. These have been compared to determine the most cost effective solution not only for the single CNG ship but mostly for the fleet composition in a given transport scenario.

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The Bucintoro project has been relaunched after years in stand-by under the name of Bucintoro of the Third Millennium . Many contributors from Italy and even from France have accepted the challenge with the purpose of building the modern version of the last Bucintoro burned by Napoleon troops at the end of the Venetian Republic. The previous phase of development brought to a business plan aimed at managing the building and management of the new golden vessel. The hull form of the new Bucintoro will be a perfect copy of the historical one with a special double deck galley inclusive of a lower deck for 168 rowers seated in four at 21 oars each side and an upper deck for authorities, both fitted now with modern systems in order to improve safe navigation. The complete structural scantling drawings with midship section have been already certified by RINA classification society. After a summary on the age-old history of the vessel and a review of technical issues developed and already certifed, this paper addresses the primary static and hydrodynamic issues. To this end, optimal subdivision of internal volumes to comply with intact and damage stability rules as well as theoretical assessment of resistance and powering performance are carried out. Since the Bucintoro will sail in an urban area, in the restricted waters of the Venice Lagoon and in natural parks, manoeuvring and hybrid propulsion are of major concern also to cut emissions. All these issues will be theoretically assessed by means of analytical and numerical codes.

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