Still room for improvement of propulsive efficiency of ships

There is significant room for improvement of propulsive efficiency of ships with new propulsor and hull form innovations to help reduce fuel consumption and add to the decarbonization efforts of the shipping industry, Finland-based research institute VTT said.

Illustration; Image by Offshore Energy

Propulsive efficiency translates to the amount of power delivered to the propeller that can be used for propelling a ship. At the moment it stands around 70 percent.

This kind of improvement is not dependent on fuel types, according to VTT, which claims that the discussion around decarbonizing shipping has been largely focused on future fuel types such as ammonia and hydrogen.

“However, innovations and improvements in propulsion technology and hull form should not be forgotten. By developing efficient propulsion concepts, the fuel consumption can be reduced regardless of the used fuel type,” VTT said.

The institute is currently engaged in a project on developing new methods to model underwater noise, a major environmental issue in the shipping industry, and propeller cavitation phenomena. By better understanding the sources of the underwater noise, it can be mitigated more effectively.

“The main goal of the research project is to significantly increase the propulsive efficiency of ships by developing new propulsion concepts. An increase in propulsive efficiency leads directly to lower fuel consumption and lower emissions. Concurrently we are looking for solutions to lower the underwater radiated noise of ships,” says research scientist Ilkka Perälä who is leading the project at VTT.

VTT has received € 1.2 million ($1.208 million) funding from Business Finland for UltraPropulsor Co-Innovation project. The project develops future solutions for zero-emission shipping. The total budget of the co-innovation project is € 4.5 million including the industry partner budgets. VTT contributes to the project with strong hydrodynamics expertise and materials science to minimize ship energy consumption and enable the development of novel low emission solutions and concepts.

Industrial partners in the project are ABB, Foreship, ATA Gears and Composite Solutions and Innovations.

The main topics of the research project include hydrodynamic research to demonstrate the feasibility of novel solutions by numerical modelling and experiments, and material research to develop methods for strength assessment of propeller blades.

Material research aims to techno-economic optimization of the future propeller materials. Life cycle cost assessment, manufacturability, and material properties, especially fatigue strength, and corrosion resistance in operational conditions constitute key criteria. Furthermore, novel methodology for the defect-tolerant design of the propeller material will be developed.