Feasibility project for shipping cng from cyprus to North Adriatic arc

The rationale of CNG option in prospective regional markets like the Mediterranean is that the offtake and delivery of small-to-medium sized gas fields are less competitive for subsea pipeline and especially LNG transport modes. The needed integration between logistics and conceptual ship design has been the main driver to this paper. To this end, a rational scheme has been implemented which integrates a menu of CNG prototype ships into a logistics framework. The main goal is selection of the optimal fleet configuration for shipping the compressed natural gas from the Aphrodite basin to the Northern Adriatic Arc with various export rates for a given number of gas production years. The final result of this paper is a self-standing feasibility study for the marine transport of CNG across the East Med corridors, complete of cost evaluation, at an accuracy level sufficient to make decision on possible implementation of this transport mode as an economically convenient alternative to subsea pipelines

DETERMINATION OF AN OPTIMAL FLEET FOR A CNG TRANSPORTATION SCENARIO IN THE MEDITERRANEAN SEA

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

A Model for Intact and Damage Stability Evaluation of CNG Ships during the Concept Design Stage

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

Effect of Different Propulsion Systems on CNG Ships Fleet composition and Economic Effectiveness

The compressed natural gas (CNG) transport is becoming nowadays an attractive solution not only for stranded gas shipping where current technologies like lique\ufb01ed 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 signi\ufb01cantly reduce the ship displacement in case of PVs Type 3 and Type 4 when compared to existing prototype designs with PVs Type1 and Type2, also leading to completely different hull forms. Since CNG ship design is a new research \ufb01eld 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 in\ufb02uencing 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 \ufb02eet composition in a given transport scenario

RISK-BASED SYSTEM TO CONTROL SAFETY LEVEL OF FLOODED PASSENGER SHIPS

Predicting the consequences of flooding is a key issue that may help the ship master of a large passenger ship to make rational decisions in emergency situations. To this end, the Delphi Emergency Decision Support System (Delphi EDSS) has been designed and is under implementation to continuously assess ship’s state of survivability. Analyses are performed by means of a time-domain simulation program, where transient stages of flooding are investigated and stored off-line for all the potential damage scenarios. The Delphi EDSS evaluates the ship risk level including the most important aspects related to safety state while establishing the time-to-capsize which is of primary concern for the safe evacuation of the damaged ship. The methodology is based on a scientific approach, setting an overall platform for rational assessment of non-survivability risk. Determination of the global risk level and its components requires solution of a multicriterial problem, where the level of importance of each criterion contributing to determination of a global risk index is combined with fuzzified contributors to risk calculated at lower levels

The Bucintoro Preliminary Design: Static and Hydrodynamic Assessment

The Bucintoro project has been relaunched after years in stand-by under the name of \u201cBucintoro of the Third Millennium\u201d. 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

Concept Design Methodology to Enable Naval Smart Grid onboard Electric Ships

The design of naval electric ships is a complex task, requiring the combined effort of several experts to provide a feasible, efficient, and effective design. In this regard, modifying an existing \u201cparent\u201d design still seems to be the easiest way to achieve cost reduction, acquisition process anticipation, and reduced technical risks. In last decades, many methods have been proposed to approach new design concepts. In this paper the authors support the use of set-based design (SBD) paradigm, especially at concept design stage, with the aim of identifying the best possible design enabling naval smart grid onboard. A synthesis is made of the primary properties of a number of baseline ships, to ease the metamodeling of ships\u201d attributes. The latter are used to drive a random mathematical design model in a MADM framework. A large set of feasible designs is generated by an adaptive Monte Carlo sampling, followed by identification of the Pareto frontier and selection of the best designs through a rank ordering. In this paper it is shown how the best non-dominated designs can improve performance, while providing a significant advantage compared with the baseline ships in terms of lower onboard occupied volumes and weight. The latter can then be used for installing additional equipment onboard the vessel, like energy storage systems, in order to enable the integration of modern and future electric systems. A preliminary assessment of the achievable energy storage capacity enabled by the SBD approach is also given, to allow evaluating the order of magnitude of the advantages provided by the SBD approach

Fuzzy Analytical Hierarchical Process to Assess Weights of Importance in Ship Operation Risk Assessment

The evaluation of the safety state of the ship in a generic operative or emergency condition is a very complex issue due to the huge number of attributes involved in the problem, uncertainties of their values and assessment of their mutual importance. The safety of the ship shall be presented in a simple and immediate manner in order to provide a useful decision support to onboard personnel. That is why a hierarchical risk assessment procedure has been developed selecting a set of attributes which are grouped in criteria and sub-criteria. The attributes are fuzzified and combined in order to obtain a risk index for each sub-criterion and criterion. The mutual importance of criteria, sub-criteria and attributes is assessed by means of a Fuzzy Analytical Hierarchical Process (FAHP), which rationally incorporates and treats the experience of masters and officers collected by a survey. This process allows summarizing experience and proficiency into a decision support system devoted to increase ship safety, while providing an interesting representation of the onboard perception about risk and its main causes

Integrated design of an eco-friendly wooden passenger craft for inland navigation

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