This work demonstrates the advantages of using laser powder bed fusion for producing a rudder bulb of a moth class sailing racing boat via laser powder bed fusion (LPBF). The component was designed to reduce weight using an AlSi7Mg0.6 alloy and incorporated a biomimetic surface texture for drag reduction. For the topological optimization, the component was loaded structurally due to foil wing’s lift action as well as from the environment due to hydrodynamic resistance. The aim was to minimize core mass while preserving stiffness and the second to benefit from drag reduction capability in terms of passive surface behavior. The external surface texture is inspired by scales of the European sea bass. Both these features were embedded to the component and produced by LPBF in a single run, with the required resolution. Drag reduction was estimated in the order of 1% for free stream velocity of 2.5 m s⁻¹. The production of the final part resulted in limited geometrical error with respect to scales 3D model, with the desired mechanical properties. A reduction in weight of approximately 58% with respect to original full solid model from 452 to 190 g was achieved thanks to core topology optimization. Sandblasting was adopted as finishing technique since it was able to improve surface quality while preserving fish scale geometries. The feasibility of producing the biomimetic surfaces and the weight reduction were validated with the produced full-sized component.

To tackle the significant increase in traffic congestion and pollution in urban areas, waterborne transport systems can offer a more efficient and environmentally friendly alternative, decreasing traffic congestion on roads, noise, and pollution emissions, with reduced infrastructure requirements. Developing a sustainable waterborne passenger system requires a multidisciplinary approach and a systemic view, which involves various stakeholders and knowledge. Digital transition can encourage a better management of resources and enables systems integration promoting circular economy and ecosystem models, which create interrelations among systems. The aim of this study is to identify circular practices adopted in the waterborne passenger mobility (WPM) ecosystem driven by digital technologies. A holistic perspective which considers all the system of actors and their mutual interactions has been adopted. Five case studies have been selected in Northern Europe and analyzed by applying the Smart Circular WPM Ecosystem framework, previously developed by the authors. The analysis identifies a list of Smart Circular practices resulting from the application of digital technologies during specific lifecycle stages, involving certain actors’ categories, and enabling circular principles. The case studies analysis also highlighted unexplored or under-considered fields of action which can be the base for further research.

In addition to fulfilling their primary function, the so-called “status-symbol” objects also vehicles of deeper meaning. Among them, yacht have been often seen as a tool to convey messages of different content throughout the years. The aim of this study is twofold: to show the evolution of yacht design meaning during the last decades, and to outline the future one, according to the redefinition of the concept of luxury goods, category of which yacht belong. The study results confirm that the yachting sector is starting to adopt new perspectives toward sustainability and that, to succeeded in this, the multidisciplinary of design is an essential aid, if not the only possible way to tackle the challenge to convey new messages.

The present paper reports the comparison of the ship motions and added resistance assessment using high fidelity RANSE simulations in virtual towing tank LincoSim, using 2D strip theory as implemented in ShipX v4.4.0 and 3D BEM potential flow software Hydrostar v8.2.1. All calculations are performed for a medium-sized RoPax ferry of Levante Ferries fleet, which operates daily routes in the Ionian Sea. Calculations by ShipX are performed in frequency domain (using strip-theory and direct pressure integration) and in time domain. The high-fidelity RANSE seakeeping modeling is based on the open-source CFD code OpenFOAM v12 using a standardized framework, tailored to take advantage of HPC facilities and based on a forcing zone formulation. The CFD simulations are performed for six wave periods in head and beam seas at the constant wave height of 3 m. Comparison of the obtained results shows that potential-flow methods are very efficient and reliable tools, suitable for the massive calculations in the first stages of the project. High-fidelity RANSE modeling seems to be more suited for selected cases such as analysis of roll and added resistance in beam waves.