A little on the tech

The simulator integrates the equations of motion in real time or faster, driven by hydrodynamic and aerodynamic forces computed at each time step. Wave orbital velocities are evaluated at the instantaneous position of every foil, so seakeeping loads are physically accurate rather than pre-tabulated. Control inputs flow through a virtual actuator framework that mirrors real hardware (elevator, rudders, ailerons, canards, flaps, and thrust-vector control), making the simulator a direct testbed for flight control algorithms.

Methodology

The simulator is structured as a MATLAB class-based plant model coupled to a Simulink integration loop. At each time step, the Boat object computes net forces and moments in the body frame by iterating over all attached Foil, Hull, Propulsor, and Aerodynamics objects. Each Foil evaluates its angle of attack from the local inflow, which combines the rigid-body velocity (linear plus rotational) with the wave orbital velocity at the foil's current world-frame position. Lift and drag are read from tabulated 360-degree polars, corrected for finite span. The Hull object contributes buoyancy (based on draught computed from the instantaneous waterplane intersection of the imported STL geometry) and viscous resistance. The net force and moment vector is passed to Simulink, which integrates the 6-DOF Newton-Euler equations and returns updated position, velocity, and attitude for the next step. Virtual actuators map logical control demands (e.g. elevator command) to deflections of the relevant physical foils, including sign-reversal conventions, so that the same control law operates correctly across different vehicle geometries.

Key Capabilities

• Full 6-DOF dynamics: Surge, sway, heave, roll, pitch, and yaw are all resolved. Inertia tensor, CG position, and mass are configurable per vessel.

• Multi-component irregular sea state: Directional, multi-frequency wave fields (JONSWAP or user-defined spectra) with independent heading, amplitude, and phase for each component. Wave forces are computed at the actual submerged foil positions.

• Object-oriented vessel definition: Hull, foils, propulsors, aerodynamics, and sensors are assembled from modular class instances. Switching from an e-foiler to an AC75 racing yacht or a naval patrol craft is a matter of swapping the definition file.

• Virtual actuator framework: Physical foils are mapped to logical controls (elevator, aileron, rudder, TVC) via a sign-convention-aware coupling layer. The same control law runs unchanged across different vehicle configurations.

• GPS-referenced route following: Waypoints are specified in  latitude/longitude. The simulator tracks position and heading along a defined course, enabling mission-level analysis.

• Sonar and altimeter sensor models: Virtual sonar transducers at configurable hull positions provide altitude-above-water readings including wave-surface effects, directly equivalent to the sensors used in real flight controllers.

• 3D real-time visualisation: The vessel and its foil system are rendered in a 3D scene from imported STL hull geometry, with lighting, wave surface, and force vectors. Video export is built in.

• Hardware-in-the-loop ready: The Simulink model architecture is compatible with HIL setups, allowing physical flight controllers to be plugged in and tested against the simulated plant.

• Validated vehicle library: Pre-built configurations include  e-foilers , Sailboats, foiling monohull, a foiling RIB, etc.  

Typical Usecases

• Flight controller development and gain tuning before sea trials.

• Seakeeping assessment: quantifying motions and structural loads in irregular waves.

• Control law validation across the full flight envelope including take-off and touchdown.

• Sensor placement studies: comparing altimeter positions for ride-height control.

• Mission planning and energy analysis along GPS-defined routes.

• Training simulators for autonomous or remotely operated foiling vessels.