How NavCad and Orca3D Marine CFD Work Together to Improve Vessel Design


Author: Larry Leibman 
 
In marine hydrodynamic design and analysis, accurately representing the principal forces involved in the problem have a significant impact on the predicted performance. Whether you're designing a workboat, patrol craft, or recreational vessel, understanding how your design will perform in real-world conditions is essential. That’s why we’re excited to highlight a recent case study from our partner HydroComp, “Enhancing Marine CFD Simulation Fidelity with NavCad”, which demonstrates the power of combining HydroComp’s NavCad® with Orca3D Marine CFD. 

Together, these tools help naval architects and marine engineers make more informed decisions, reduce guesswork, and deliver higher-performing vessels. 

 

A Real-World Example: Offshore Planing Craft 

The HydroComp study focuses on a 12.7-meter (roughly 42-foot) twin-screw offshore planing craft designed for 30-knot operation. Initially, the team used established semi-empirical methods within NavCad to estimate critical performance factors such as resistance, trim, and propeller lift. These estimates created a solid baseline to configure a high-fidelity Orca3D Marine CFD simulation, resulting in greater simulation accuracy and deeper insight into local flow effects.  

Figure 1) Orca3D model twin-screw offshore planing craft 

Why Combine NavCad and Orca3D Marine CFD? 

NavCad uses proven empirical methods and historical data to estimate how a vessel will perform hydrodynamically. These fast, reliable estimates help validate your design before transitioning into higher fidelity, albeit more computationally expensive, fluid flow CFD simulations. On the other hand, Orca3D Marine CFD provides high-resolution insight into water and air flow, trim, resistance, and hull-propulsor interactions, revealing important nuances you won’t get from empirical methods alone. When used together, they offer a hybrid modeling workflow that’s greater than the sum of its parts. 

  • NavCad provides fast resistance and propulsion benchmarks, including estimates for vertical lift from the propellers. 

  • Orca3D Marine CFD takes those values further, allowing for detailed analysis and flow visualization at model or full scale. 

Key Insights from the Study 

One of the most impactful findings came from modeling vertical lift and thrust-line forces produced by the propellers. These forces, often left out of traditional performance prediction models, were shown to significantly affect trim and resistance, especially at medium speeds where the vessel transitions to planing mode.

The team used propeller open water curves (J/Kt/Kq) generated in NavCad (and corrected for shaft angle and rise of run) in Orca3D Marine CFD to run a full self-propulsion simulation using an actuator disk model. To reflect the propeller vertical lift forces in CFD, these forces were obtained from NavCad and added as force vectors in Orca3D Marine CFD. The result? A much more realistic and accurate simulation of the boat’s running trim and behavior under power. 

Figure 2) Impact of Propeller Force Modeling on CFD Resistance Predictions 

The Bottom Line: Better Simulations, Better Boats 

When you combine NavCad’s fast, trusted parametric analysis with Orca3D Marine CFD’s detailed, physics-based simulations, you unlock a more complete and accurate way to evaluate vessel performance.

This integrated approach allows engineers and naval architects to: 

  • Validate early design concepts more confidently 

  • Reduce errors and reruns in CFD by setting realistic benchmarks 

  • Simulate vessel behavior more accurately under real-world conditions 

  • Optimize performance through smarter propulsion modeling 

Try Orca3D Marine CFD Today 

Orca3D Marine CFD is built specifically for marine professionals. It’s easy to learn, powerful, and affordable—ideal for anyone designing vessels of all types and sizes. Download a free trial and see how it can improve your simulation workflow.  

For more case studies, product news, and tips from the field, follow Orca3D on LinkedIn. 

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