The effectiveness of any alternative propulsion system lies in its ability to convert naturally-generated energy into thrust. In the ocean, one of those energy sources is waves.

To harness this power, Dr Liang Yang, Lecturer in Marine Renewable Energy Systems at the Centre for Energy Engineering, Cranfield University, looked to an uncommon propulsion system: flapping hydrofoils.

The idea of using flapping-based propulsion, which draws its inspiration from the natural world, is not new.

“We have engineered propellers, which are very efficient, but animals generate thrust by flapping a tail, a wing, for example,” explains Yang.

Flapping-based propulsion systems can be found on uncrewed surface vessels, such as wave gliders. These hydrofoils move passively with the motion of waves, generating propulsion. Yang says it wasn’t clear whether this ‘wave-devouring propulsion’ could be applied to larger vessels.

There are many aspects to consider. “We needed to understand the theory so we could design all the elements of the system, so we spent a long time investigating the physics behind this type of system,” says Yang.

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Read the full article Propelling change in shipping decarbonisation at The Marine Professional.