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In the present paper an experimental and numerical analysis of an unconventional CLT propeller is carried out. Two different numerical approaches, a potential panel method and an RANSE solver, are employed. Cavitation tunnel experiments are carried out in order to measure, as usual, thrust, torque, and cavity extension for different propeller working points. Moreover, LDV measurements are performed to have a deep insight into the complex wake behind the propeller and to analyze the dynamics of generated tip vortexes. The numerical/experimental analysis and comparison of results highlight the peculiarities of this kind of propellers, the possibility to increase efficiency and reduce cavitation risk, in order to exploit the design approaches already well proven for conventional propellers also in the case of these unconventional geometries.

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Strong restrictions on emissions of engines for marine propulsion (particularly SOx, NOx) will probably be adopted in the near future. In this paper, by using specifically developed simulation techniques, a COGAS plant solution is proposed in substitution of the originally adopted prime mover (a two stroke low speed diesel engine), for the propulsion of a large container ship, whose characteristics and performance are known. Starting from the performance and cycle characteristics of an existing gas turbine, the COGAS steam cycle characteristics and related components are defined through an original design procedure. The combined cycle is compared with a Diesel engine, not only with regard to the plant performance and efficiency at design and high load off-design conditions, in both steady state and dynamic situations, but also for what concerns: engines dimensions and weights, engine room layout, overall propulsion plant weight, ship hull loading capacity, economic considerations.

Additive manufacturing (AM), or three dimensional printing, is a modern way to build objects with possibly a high degree of accuracy and favorable cost/benefit ratio. This approach is widely used by many manufacturing industries and a certain interest for this innovative production technology is also growing in the ship design and production field. To this regard, the experimental activity at the model scale is often necessary for the ship performance assessment in the design phase. In the article, preliminary results of a propeller model for the cavitation tunnel, built with additive technology, are presented, showing the strengths and weaknesses of the printed model. Moreover, as an introductive overview, different AM technologies are briefly described, with the aim to point out potential applicability to ships.