“Supporto alla realizzazione di progetti complessi di attività e di ricerca e sviluppo per le imprese aggregate ai poli di ricerca ed innovazione”

European Regional Development Fund

Goals of the project

Among the goals of the project are:

  1. the study, the design development and the experimental validation of an innovative thruster for boats and mega yachts;
  2. the application of innovative technologies, based on addictive manufacturing, in order to realize propeller models andreal-size blades.

Contents of the Project

The project includes:

  1. Definition of the configuration and the FEM dimensioning of the mechanical constraint, in the case of a single-stage built-up propeller with conventional optimised shape
  2. Designing and hydrodynamic verification of multistage propellers, with different shape of the blades, optimised for every stage
  3. Metallic 3D printing of blade models for experimental testings (Dmax 250 mm)
  4. Metallic 3D printing of at least one pala al vero to be mounted on the Benedetti Mediterraneo watercraft (D-propeller 1400 mm, weight of the blade 45 kg)

Built-Up Blades

The project focuses on the study of a thruster with built-up blades. This solution brings many advantages if compared to a traditional propeller:

  1. Handling of minor weights
  2. Repairing / substitution only for the damaged part
  3. Shorter production times, thanks to smaller dimentions
  4. It allows us to use innovative technologies for the production of blades (metallic print and CNC machines)

Over the course of the project, we considered two different solutions of blades, but we finally opted for the Built-up propellers (BUP): the hub of the propellers presents a flanged coupling with the shaft line and with the blades (via bolts). In this case it is not possible to modify the pitch.

Multistage Propellers

The projects includes the hydrodynamic study through numeric fluid dynamic analysis. It also includes experimental verification tests for the realization of propellers with multistage blades, potentially more efficient than the traditiona propellers.

Metallic 3D Printing

Finally, the project also includes the study, among different 3D printing technologies, of those which are the most suitable to realize propeller models for experimental tests and for real-size blades.

For these propeller models, we are going to realize DMLS (Direct Metal Laser Sintering) prototypes and Polijet prototypes (this is a plastic material covered in nickel). Both these technologies potentially offer the necessary dimensional precision. For the real-size blades we are going to use the WAAM technology (Wire Arc Additive Manufacturing).

Here you can see a metallic propeller designed by Detra and realized with “Kinetic Fusion” additive technology  by Titomic, and presented at “Pacific 2019 International Maritime Exposition” in Sidney.