Performance analysis and yacht design optimisation CFD for MOTOR YACHTS & SAILING YACHTS
Cape Horn Engineering has pioneered RANSE based CFD since its very beginning and continues its research work on a daily basis. Thanks to our proven expertise in the America’s Cup, Volvo Ocean Racing, and other high profile sporting events, we apply this yacht design optimisation CFD technology to sailing yachts and motor yachts, fully foiling and foil assisted high speed vessels, to improve performance, comfort, and safety, increase energy efficiency, and reduce emissions.
What is yacht design optimisation CFD?
Yacht design optimisation CFD is the use of high fidelity Computational Fluid Dynamics simulation to improve the speed, seakeeping, comfort, and safety of a yacht before it is built or refitted. For sailing yachts this means coupled hydrodynamic and aerodynamic analysis of the hull, appendages, and sails across a matrix of heel, yaw, and rudder angles. For motor yachts it means full scale resistance, self propulsion, seakeeping, and manoeuvring, with cavitation and Fluid Structure Interaction (FSI) where appendage loads and comfort at speed really matter.
Cape Horn Engineering is a UK based specialist yacht design optimisation CFD consultancy. We apply full scale RANS CFD to sailing superyachts, motor yachts, performance cruisers, and fully foiling and foil assisted high speed craft, helping yacht designers, naval architects, shipyards, and sailmakers make evidence based decisions on hull shape, appendage configuration, rigs, and sails.
Key considerations
- Who we serve: yacht designers, naval architects, shipyards, sailmakers, and owners of sailing and motor yachts, performance cruisers, and foiling craft.
- What we deliver: full scale RANS CFD for hull and appendage optimisation, sail aerodynamics and VPP inputs, resistance and self propulsion, cavitation and FSI, seakeeping, and 6 DOF manoeuvring per ITTC procedures.
- Proof points: 117 simulation VPP campaign for the Frank Neubelt C-140 sailing superyacht with North Sails Design Services, performance assessment for a Werner Yacht Design 25m motor yacht, coupled hydro and aerodynamic analysis of the award winning Najiba (Philippe Briand, Vitruvius Yachts), Windy SLR60 seakeeping with Malcolm McKeon Yacht Design, Fleming 85 4 DOF surging in waves, and keel configuration selection for the E-volution Classic 47m cruising sloop.
- Tools: Simcenter STAR-CCM+ on in house and cloud HPC infrastructure.
- Extra service: the AeroSim Portal online sail design service for sailmakers, naval architects, and yacht designers.
Using CFD Technology
Cape Horn Engineering’s yacht design optimisation CFD toolkit covers the full range of flow behaviours a yacht designer or naval architect needs to resolve, from the free surface around the hull to the pressure field on the sails.
- Free surface and viscous flow modelled simultaneously, at full scale.
- Full scale resistance, self propulsion, and delivered power for motor yachts.
- Coupled hydrodynamic and aerodynamic analysis for sailing yachts, feeding Velocity Prediction Programs (VPPs) with force and moment data across heel, yaw, and rudder angles.
- Fluid Structure Interaction (FSI) for appendages, foils, and sails.
- Cavitation analysis on propellers, hydrofoils, and high speed appendages.
- Foil section optimisation loops that account for transition and cavitation.
- Automated shape optimisation of hulls and appendages using neural network response surface models and optimisation algorithms.
- Seakeeping and 6 DOF manoeuvring, including motions, accelerations, added resistance, and ITTC compliant manoeuvre trials.
- Advanced flow visualisation and post processing, delivering load cases, internal forces, and moments that designers can feed directly into appendage and rig dimensioning.
We share these outputs with clients through images, video animations, and interactive visualisation files, and we use virtual and augmented reality where they add value. Simulations run on our High Performance Computing (HPC) cluster using Simcenter STAR-CCM+ from Siemens Digital Industries.
Why full scale CFD changes the yacht design process
Historically, yacht designers and naval architects have relied on towing tank tests to validate their final designs. However, the force similarities between a scaled physical model and the real yacht cannot be achieved in a towing tank, which makes those tests complex and reliant on assumptions and empirical formulations.
Our yacht design optimisation CFD workflow models the vessel at full size, capturing the stern wake and boundary layer effects directly at full scale, with realistic moments of inertia and centre of gravity. Forces and moments can be decomposed by component (hull, rudder, keel, fins, foils, propellers) and by physical origin (friction and pressure). Because no engineering component is ever isolated from its effect on the whole system, we run the hull, appendages, propellers, and rig simultaneously, so the design process can be steered holistically for speed, comfort, and safety.
The same full scale yacht design optimisation CFD framework also supports aerodynamic simulations around the superstructure and sails, capturing wind effects around exhaust vents, deck comfort zones, and sail interaction with the rig. Compared to physical models, this workflow delivers substantial reductions in project time and cost.
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 vessel motions, velocities, accelerations
- 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 where 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, 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
Case Studies
See our case studies on Ship Optimisation
Simulations
Seakeeping accelerations for the Windy SLR60 with Malcolm McKeon Yacht Design
Self-propulsion CFD simulation for the award-winning superyacht Najiba, with rotating propellers at a constant RPMto calculate the vessel speed and shaft power. The yacht is modeled in detail, with all appendages including roll sabiliser fins included.
Examples of CFD simulations carried out for motor yachts and commercial ships. Resistance, propulsion, seakeeping, slamming, exhaust gas on deck.
Demonstration for a 4 Degrees-of-Freedom simulation, with freedom for the yacht to move naturally though the waves. The open-water propulsion is based on the yacht propeller. The propeller torque and RPM is kept onstant, and thrust and delivered power are variable.
Turning circle manoeuvre of a 50m superyacht following the ITTC recommended procedure for full scale manoeuvre trials. 6 DOF simulation with active rudders and fin stabilisers.
Cape Horn Engineering were proudly commissioned for their technical expertise to evaluate the sailing performance for 3 candidate keel configurations on the E-volution and Classic 47 metre cruising sloop.
Our Sail Design Service
Our online CFD computations are for sail makers, naval architects and yacht designers.
State of the art aerodynamic technology and high fidelity simulations to optimise your sail design and increase sailing performance.
We will analyse and evaluate the performance of your sails (and the boat), from a single sail design to multiple geometries, weather conditions and racecourse conditions. Accurate results of the best possible sail geometry plus an efficient visualisation of the sail loads will be available in just a matter of hours.
