SUPERYACHT DESIGN OPTIMISATION

Investigating carbon free energy alternatives and design solutions

Superyatchs

Cape Horn Engineering have pioneered RANSE based CFD since its very beginning and continues its research work on a daily basis. Due to our proven expertise in the America’s Cup, Volvo Ocean Racing and other high profile sporting events, we can apply this cutting edge technology to a wide variety of other marine applications including superyachts, sailing yachts and motor yachts, fully foiling and foil assisted high speed vessels, to improve performance, comfort and safety, increase energy efficiency, and to save fuel and reduce emissions.

Using CFD Technology

We use advanced visualisation techniques to understand the flow features and to share that knowledge with clients. We post-process the simulations in a way that the designers obtain load cases and internal forces and moments for dimensioning the appendages of their designs. We carry out Fluid Structure interaction for appendages and sails. We assess cavitation in the appendages of all high speed craft. We have developed foil section optimisation loops that take into account transition and cavitation. For extensive design campaigns we optimise hull and appendage shapes using modern optimisation techniques like neural networks response surface models and optimisation algorithms.

CFD technology is a huge benefit for naval architects when optimising any vessel. Historically, designers have used more traditional technology, such as towing tank tests for their final designs to make sure they meet their clients’ requirements. But the force similarities between the model at scale and the real yacht cannot be achieved in a towing tank, which makes testing complex, based on assumptions and empirical formulations.

Using our CFD technology eliminates this problem, since it models the vessel at full size, and captures the stern wake and boundary layer effects directly at full size. Other advantages of CFD compared to tank testing is that realistic moments of inertia and VCG are easily achievable in simulations as well as the decomposition of forces and moments by components like hull and appendages, and by physical origin like friction and pressure. Moreover, CFD offers a greater insight into the details of the flow through images, video animations or interactive visualisation files. Even virtual and augmented reality is starting to make an impact today. CFD also offers substantial reductions in time and costs compared to physical models.

A good design process involves investigating the hull with its appendages and propellers simultaneously, as there is no isolated engineering component without an effect on the whole system. CFD allows us to perform calculations on the system as a whole, so the design process can be steered for fuel efficiency, comfort and safety.

CFD technology can also be used for aerodynamic simulations to capture wind effects around exhaust vents in order to investigate where the smoke will travel for passenger comfort.

Advantages of CFD compared to tank testing

  • All simulations are at full scale
  • Simulations use realistic inertias and centres of gravity (something not feasible in tank testing)
  • Oblique incident waves coming from any direction can be simulated, tank testing is usually limited to head waves
  • Decomposition of individual forces and moments for the hull and each appendage
  • Precise analysis of motion velocities, accelerations and trajectories of the body
  • Flow visualisation and animation to gain insight and understanding about differences between designs
  • Simulations are 100% reproducible
  • Hull or appendage shapes can be easily changed without building new models
  • It is easy to test many design configurations i.e. to swap appendages Easily test in a variety of sailing conditions (speed, wave characteristics) to compare performance
  • Time and cost reduction
 

Areas we can help...

  • Hull and appendages performance and optimisation
  • Propulsion, propeller selection, fuel consumption, delivered power
  • Cavitation on propellers and Energy Saving Devices (ESD)
  • Energy Efficiency Design Index (EEDI)
  • Manoeuvres according to ITTC procedures
  • Appendage torque and bending moments, load cases
  • Seakeeping, added resistance, motions and accelerations
  • Slamming loads, water on deck, sloshing
  • Global ship bending moments in waves
  • Damage stability and ship launching, life boat launching
  • Roll damping, performance of fin stabilisers, trim tabs and interceptors
  • Fully foiling and foil assisted vessels
  • Cavitation on hydrofoils and 2D foil section optimisation
  • Fluid Structure Interaction (FSI) of appendages
  • Occupant safety and comfort including local wind effects and exhaust gas
  • Windage and structural wind loads on superstructures Ship Helicopter Operating Limits (SHOL)

* Engine room and cargo hold and cabin ventilation

Benefits of using CFD technology

  • Improved propulsion
  • Improved fuel efficiency – fuel savings of at least 5% are realistic
  • Reduced emissions
  • CFD investigation can reduce the safety margin to avoid over-powering your vessel
  • Improved seaworthiness
  • Improved comfort

Simulations

Najiba Self‑Propulsion Simulation

CFD simulation of the award-winning superyacht Najiba with rotating propellers, stabiliser fins, and full superstructure. Speed and shaft power determined under constant RPM.

C‑130 Yacht Performance Study

117 CFD simulations on the C‑130 superyacht by Frank Neubelt to optimize comfort vs. performance. Results fed into North Sails’ Velocity Prediction Program.

Roll Decay Testing via RANS

Dynamic roll decay simulations at full scale to calculate damping from various appendages. Roll motion tracked after release from 10° heel with zero speed.

Windy SLR60 Seakeeping

CFD-based seakeeping study for the Windy SLR60 yacht, in collaboration with Malcolm McKeon Yacht Design, to assess onboard accelerations.

Najiba Windage & Comfort Analysis

CFD analysis of side wind impact on lateral resistance and onboard comfort for superyacht Najiba. Combined aero-hydro simulation with full geometry.

CFD for Yachts & Commercial Vessels

Examples include resistance, propulsion, seakeeping, slamming, and exhaust flow simulations for both yachts and commercial ships.

Fleming 85 in Quartering Waves

4-DOF CFD simulation of the Fleming 85 in 2.5 m quartering waves. Vessel shows dynamic surging with speeds fluctuating ±7 knots from calm-water conditions.

50 m Yacht Turning Circle

6-DOF CFD manoeuvring trial following ITTC procedures. Active rudders and stabilisers used to simulate turning circle of a 50 m superyacht.

Keel Comparison for 47 m Sloop

Performance comparison of three keel options for the E‑volution and Classic 47 m cruising sloops using advanced sailing CFD analysis.