The increasing interest in air pollutant emissions reduction also influences the shipbuilding industry. In this sense, hybrid-electric propulsion is a promising solution for green navigation, ensuring a Zero Emission Mode navigation close to coastal areas and harbors. Hybrid-electric propulsion is a convenient choice not only for new units but also for the retrofitting of outdated ones. This paper deals with an example concerning the retrofitting of a small passenger vessel, where the study of the application of hybrid-electric systems was possible only thanks to reverse engineering techniques for the identification of the internal spaces. The final hybrid configuration refers to a slow-tourism operative profile in the North Adriatic area.

Sustainable mobility is one of the most challenging issues for passenger transport inside environmental protected areas and ecologically fragile environments. To reduce the pollutant emissions, the adoption of electric or hybrid-electric solutions for crafts propulsion is a suitable option for green navigation. However, the operation in restricted basin leads also to specific critical issues for the vessel sailing, as dealing with shallow or restricted waters and transit under low air-gap bridges. The combination of these constraints with the adoption of a hybrid-electric propulsion system increases the design difficulties also for a small craft, requiring the use of advanced simulation models to assess the vessel performances. This work presents a simulation model for a small passenger craft that will operate in the Grado Lagoon. The model combines the hydrodynamic issues of manoeuvring and propulsion in restricted water with the simulation of the electric loads and capacity of the energy storage system installed onboard. The simulations performed with the developed simulation system are in accordance with data measured during trials on a prototype of the vessel. The developed model is a powerful tool for designers in order to rapidly assess the green capabilities of new projects since the early design stages.

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.

Tethered escort of ships is performed by specially designed tugs linked by a tow-line to a strong point aft of the assisted ship. In fact, the tug is called to control the course and speed of the assisted ship in an emergency situation), so reducing the risk of grounding or collision. A substantial number of studies about ship casualties shows the grounding as the predominant accident when the ship is approaching the harbour or narrow fairways. In order to take part in escort operations, a tug must be provided with the additional service notation escort tug, which confirms its specific capabilities in accordance with particular stability criteria that will be harmonised by International Maritime Organisation from 2020. In case the tug should be propelled with Liquefied Natural Gas, then dedicated issues related to containment system should be solved. Through this paper, an overview will be given upon the possible escort operations that an escort tug could face during his operational life, together with the possible types/configurations of tugs that can be used for this kind of operations. Moreover an example will be given on the determination of escort performances by means of a self developed code on a sample tug.

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.

The increasing focus on air pollution reduction for transportation systems requires to adopt new technologies and innovative solutions to limit vehicles emissions. In case of inland waterway transportation (IWT), once vessels have to operate close to urban areas or in natural reserves, the necessity to provide a'green navigation' is of primary importance. With this specific aim, especially for small crafts, the adoption of an hybrid-electric power system grant a significant pollution reduction, leading also to a possible Zero Emission Mode (ZEM) navigation. However, the particular configuration of inland waterways makes the estimation of vessels' hydrodynamic performances harder compared to a seagoing ship, because of restricted waters effects, affecting both resistance and manoeuvring characteristics. For this purpose, time domain simulation program has been developed to estimate the effective power demand of an inland vessel during a specific route. The program has been tested on the specific case of a passenger vessel designed for the Grado lagoon, where all the reference route bathymetric data were available. By means of the simulations it has been possible to state whether the vessel is suitable to operate in ZEM mode during the service.

In order to preserve the marine environment, especially in coastal areas and close to urban areas, the reduction of pollutant emissions is of primary importance. Even though traditionally not too much effort is given to propulsion system optimization, the necessity to ensure low pollutant emission level is a constraint that must be considered in small crafts design. Moreover, very often during the design of small crafts great attention is paid to achieving the desired performance only in terms of speed. In this paper, the design of a small craft conceived as a research vessel able to operate in coastal protected marine areas is presented. The particular operational profile requires the adoption both of a hybrid-electric propulsion system and a dedicated station-keeping system. Specifically, a suitable LVDC Integrated Power System has been used to ensure Zero Emission Mode both during navigation and station-keeping operational profiles.