Session: 06-04-02 Marine Engineering and Technology - II

Submission Number: 179760

Quantifying the Impact of Ice Class Requirements on Emissions in Open Water Conditions 

Ice class requirements are essential for ensuring the safety and operability of ships in ice-covered waters. However, these requirements often compromise open-water energy efficiency, creating challenges for vessels aiming to comply with increasingly stringent environmental regulations such as the Energy Efficiency Design Index (EEDI). Despite the importance of this trade-off, its impact remains insufficiently quantified.

This study presents a semi-empirical assessment of the performance penalties associated with ice-class design features under open-water conditions, within the framework of the Finnish-Swedish Ice Class Rules (FSICR). Firstly, the effect of additional lightweight due to structural reinforcements is evaluated under two scenarios: one where displacement is held constant, and another where deadweight is maintained. In both cases, adjustments to hull geometry are necessary to compensate for the change in lightweight, which in turn affects resistance, power demand, and the attained EEDI. The impact was found to be more significant in the constant displacement scenario. Secondly, the influence of bow geometry is analyzed. Bulbous bows offer superior open-water performance by reducing wave-making resistance, but are less suitable for ice due to increased crushing loads. In contrast, ice-strengthened bows enhance ice performance but lead to higher open-water resistance. Thirdly, the impact of ice-class propeller requirements is assessed. Thicker blades, mandated for ice strength, reduce the scope for hydrodynamic optimization, leading to lower propulsive efficiency in open water. Finally, the implications of minimum engine power requirements for ice navigation are examined. These requirements often necessitate higher installed power, increasing fuel consumption, and reducing part-load efficiency in open-water operations.

Presenting Author: Shayan Rabizade Aalto University

Presenting Author Biography: Shayan Rabizade is a doctoral student from Iran specializing in marine technology. He earned his master’s degree with honors from Aalto University, where he focused on ship–ice interaction. He has continued his research at the postgraduate level within the same research group at Aalto University. His primary research interest lies in the hydromechanics of ship–ice interaction, which he investigates using both numerical modeling and experimental techniques.

Authors:

Shayan Rabizade Aalto University
Tommi Mikkola Aalto University
Mikko Suominen Aalto University