After determining a propeller open-water curve with CFD (Computational Fluid Dynamics) or another calculation method, a further analysis – especially a Propulsion Analysis – required to reliably predict the propulsion performance for a specific ship. We have developed specialized analysis software solutions that enable seamless integration into the ship design process, relying exclusively on open-source software.

From the Drift Curve to the Propulsion Analysis

The Propeller free-running curve (also called the open-water curve) describes the hydrodynamic behavior of a propeller under defined conditions—without the influence of the ship's hull. It provides fundamental performance metrics such as the thrust coefficient (K_T), torque coefficient (K_Q) and propeller efficiency $(\eta)$ as a function of the advance coefficient $(J)$.

This curve forms the basis for all further analyses, but by itself is not sufficient to represent the actual Propulsion power in real ship operation to be determined. Only a complete propulsion analysis – taking into account hull resistance, wake, suction, and mechanical losses – can provide a reliable performance prediction.

Drive analysis: Methodology and calculation steps

A complete Ship propulsion analysis typically includes the following steps:

• Resistance prediction: Determination of the total resistance of the ship at a given speed, e.g., by CFD simulation or based on recognized approximation methods (ITTC methods, Holtrop-Mennen).
• Propeller-Hull Interaction Consideration of discharge coefficient (w), suction coefficient (t), and relative rotational efficiency (η)_R).
• Operating point determination Determination of the operating point of the propeller and engine in interaction (Self-Propulsion Point).
• Performance Forecast Calculation of required shaft power, including gearbox and bearing losses.
• Sea-going and fouling surcharges: Addition of practice-relevant surcharges for operation under real conditions (Sea Margin, Fouling Allowance).

Our open-source-based software solutions

We have customized Analysis software solutions developed, based exclusively on open-source technologies – transparent, flexible, and cost-efficient. Our tools are designed to integrate seamlessly into existing design processes, whether in the early conceptual stage or during the detailed design phase.

The advantages of our open-source approach:

• Transparency and traceability: All calculation steps are openly viewable and scientifically verifiable.
• Independence from commercial licensing models: No hidden costs, no vendor lock-in.
• Interoperability Easy integration with common CFD packages (e.g., OpenFOAM) and other design tools.
• Customizability Full customization to project-specific requirements and ship types.
• Community and Further Development: Benefit from an active open-source community and continuous improvements.

Areas of application and ship types

Our analysis methods are suitable for a wide range of vessel types and application areas, including:

• Merchant ships (container ships, tankers, bulk carriers)
• Workboats and offshore supply vessels
• Ferries and passenger ships
• Research and Special Vehicles
• Sports boats and yachts

Conclusion: Efficient performance prediction in modern ship design

The combination of precise CFD-based propeller analysis and a structured drive analysis forms today's State of the art in hydrodynamic ship design. With our open-source software solutions, we offer naval architects and design offices a powerful, transparent, and cost-effective tool – from the free-running curve to the final performance prediction.

Contact us to learn more about our analysis methods and software solutions, or view our case studies and reference projects.