The design of a dynamic positioning (DP) system is a challenging task with several technical fields involved in the problem solution. Numerical simulation is a powerful tool to aid the designer during the system development and to speed up the design process. This paper presents the simulation methodology adopted to design and test the DP system for a vessel with a standard propulsion configuration. Simulation results and sea trial measurements are compared to illustrate the reliability of the proposed simulation platform.

Waste Heat Recovery (WHR) marine systems represent a valid solution for the ship energy efficiency improvement, especially in Liquefied Natural Gas (LNG) propulsion applications. Compared to traditional diesel fuel oil, a better thermal power can be recovered from the exhaust gas produced by a LNG-fueled engine. Therefore, steam surplus production may be used to feed a turbogenerator in order to increase the ship electric energy availability without additional fuel consumption. However, a correct design procedure of the WHR steam plant is fundamental for proper feasibility analysis, and from this point of view, numerical simulation techniques can be a very powerful tool. In this work, the WHR steam plant modeling is presented paying attention to the simulation approach developed for the steam turbine and its governor dynamics. Starting from a nonlinear system representing the whole dynamic behavior, the turbogenerator model is linearized to carry out a proper synthesis analysis of the controller, in order to comply with specific performance requirements of the power grid. For the considered case study, simulation results confirm the validity of the developed approach, aimed to test the correct design of the whole system in proper working dynamic conditions.

Autonomous ships represent one of the new frontiers of technological innovation in marine engineering, which demand the development of innovative control systems to guarantee efficient and safe navigation of vessels. A convenient control system should be able to command the several actuators installed on board in different conditions—for instance, during oceanic navigation, harbor approach, narrow channels, and crowed areas. Such tasks are accomplished by different switching controllers for high and low speed motion, which have to be orchestrated to ensure an effective maneuvering. An approach to the design of hierarchies of controllers for maneuvering and navigation of ships equipped with a standard propulsion configuration in both blue and narrow water is proposed. Different levels of control, from global to local, are defined and integrated to steer the vessel in such a way to increase the maneuvering capability in various scenarios.

The importance of mathematical and numerical simulation in marine engineering is growing together with the complexity of the designed systems. In general, simulation a makes it possible to improve the engineering design, reducing working time and costs of production as well. In this respect, the implementation of a simulation model for cycloidal propellers is presented. Cycloidal thrusters are being increasingly used in marine applications. Their best performance concerns low-speed applications, due to their ability to steer thrust in any direction. The proposed simulator is able to assess the performance of cycloidal propellers in terms of the generated thrust and torque, without resorting to consuming and demanding computational tools, such as CFD methods. This feature makes the presented model particularly suitable for the simulation in the time domain of the maneuverability of surface units, equipped with cycloidal propellers. In this regard, after embodying the implemented model in an already existing simulation platform for maneuverability, we show the most significant outputs concerning some simulated maneuvers, performed at cruise speed.