Seeking to make the European maritime industry more globally competitive and environmentally friendly, the EU has funded development of first hollow propeller blades.
In a project called RAMSSES (Realization and Demonstration of Advanced Material Solutions for Sustainable and Efficient Ships), lightweight, high-performance materials were used to develop the blades with additive manufacturing, in which 3-D objects are built by adding multiple layers of material. In an online article published on Marine Propulsion & Auxiliary Machinery, Patrice Vinot of project partner Naval Group, said in a statement, “Although additive manufacturing is increasingly present in industry, the programming and design of complex parts, such as propeller blades for ships, represents a considerable challenge.”
The AM process that the project used is wire arc additive manufacturing. It works by melting metal wire using an electric arc as the heat source. The wire is extruded into beads that stick together to create a layer of metal, according to the website, phys.org. The process is repeated layer by layer to create a 3-D part. WAAM can be used to create propellers up to 20’ (6 meters) in diameter.
The first demo blade is a one-third-scale hollow blade for a container ship propeller. It was printed in stainless steel in less than 100 hours and weighs approximately 661 pounds. Conventional propeller blades of a comparable size would weigh up to 22 tons. The project team hopes that when produced at full size, the propellers produced with WAAM would weigh more than 40 percent less than conventional ones.
RAMSSES is in the process of developing a full-sized hollow-bladed prop for container ships. The project is about halfway through its four-year term.