ESDP@ODC – Energy Saving Devices and Propeller at Off Design Conditions
2025 – 2028

The global shipping industry is confronted with the imperative to achieve maximum possible decarbonization. This objective must encompass not only the operational phase of vessels but also the resource-intensive shipbuilding phase. To mitigate greenhouse gas emissions during vessel operation, the implementation of Energy Saving Devices (ESDs) is becoming increasingly prevalent — including technologies such as wake equalizing ducts and, more recently, bow fins.

Efforts to achieve material-efficient designs of such ESDs are often counteracted by the safety requirements imposed by classification societies. Compliance is usually demonstrated through numerical simulations employing simplified methods and load assumptions. Actual operational loads are generally not taken into account due to the considerable computational effort and/or the complexity of the required experiments and measurement techniques. For ESDs and propellers, real operating conditions — including crash stops and extreme sea states — represent the most severe loads, yet the forces involved are not sufficiently well known. Consequently, conservatively high safety factors are applied during the design process, leading to unnecessary material and energy consumption and, in some cases, rendering hydrodynamically optimized designs unfeasible. This design stage thus suffers from a lack of detailed knowledge regarding in-service loads, as full-scale measurements remain difficult to implement. Model tests are typically performed only for design conditions, and the unsteady numerical simulation of these loads has not yet become an industry-standard practice.

Off-design conditions such as wave excitation also offer the potential to improve a ship’s energy balance by harnessing wave-induced motions to generate additional thrust through appropriately designed fin systems. A fin system that is simple and cost-effective to retrofit is probably an effective measure for reducing greenhouse gas emissions from ships. However, a validated and generic design methodology for such fin systems is currently lacking. Numerical modeling remains challenging, and experimental verification of the achieved performance gains is, to date, only partially satisfactory.

The project therefore aims to develop advanced measurement techniques for both model- and full-scale testing in order to generate robust data for more efficient propeller and ESD designs. Based on the measurement data, an experimentally validated numerical methodology for the design of a bow-fin system will be developed.