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Gomboc: yacht design and simulation tool

by Giuliano Luzzatto

Dan Bernasconi, the mind behind America’s Cup Team Emirates New Zealand’s AC75 and AC40 yacht design, also plays a pivotal role in developing Gomboc, the software that drives the design process


Gomboc stands as an innovative yacht design and simulation tool crafted by SumToZero, conceived by Dan Bernasconi with the contribution of his colleagues [see box]. Bernasconi, Jean-Claude Monnin and Mark de Gid chose the name SumToZero for the company “because when a yacht is in equilibrium, all the forces sum to zero.”

[From left] Mark de Gids, Lucie Léon and Dan Bernasconi

Technical details

Gomboc is as an advanced yacht design and simulation tool, propelled by a robust physics engine that models masses, forces, accelerations, and reference frames. Tailored components enable precise modeling of appendages, hulls, sails, wind, and waves.

The software boasts an open interface, accommodating detailed system modeling, from a simple mass-spring setup to intricate yachts with hydraulic and electronic controls.

Gomboc’s real-time models operate interactively, akin to driving or flight simulators, with seamless integration of steering wheels and other input devices for enhanced control and realism. Graphics can be rendered on monitors or within VR headsets, providing a dynamic and immersive experience.

The software also offers interactive and optimization modes, employing Gomboc’s optimization engines to iterate on design parameters for optimal performance under defined constraints.

Gomboc demo model of a power catamaran

GUI: foil design interface

A standout feature is Gomboc’s appendage foil design interface, facilitated by an intuitive GUI.

This tool allows the development and instant analysis of appendage shapes through a coupled hydrodynamic and structural solver, providing insights into lift, drag, cavitation margin, stress, deflection, and twist. Designs can be exported as 3D surfaces, streamlining the construction process.

Emirates Team New Zealand has successfully employed Gomboc in designing and building foils and rudders over the past decade.

ETNZ design team used Gomboc for the AC40 boat

Modeling environment

The software’s flexibility extends to its modeling environment, structured around interconnected blocks similar to MATLAB Simulink. This approach allows users to create custom blocks or leverage pre-built ones, enhancing the versatility of yacht design.

Beyond its GUI, Gomboc is scriptable, featuring an extensive API for code-based interactions. This not only adds depth to the user experience but also facilitates large-scale optimizations and parallel computations. The onboarding process is user-friendly, accommodating missing data through effective workarounds.

The team behind Gomboc
With a background encompassing 6 years in Formula1 and 17 years in the America’s Cup, Dan Bernasconi currently leads Team New Zealand’s design team.

SumToZero originated through collaborative efforts with Jean-Claude Monnin and Mark de Gids during their tenure at the Swiss America’s Cup Team Alinghi in 2007, at the times of 32nd America’s Cup. Together, they transformed Gomboc into a sophisticated dynamic simulation tool.

  • Dan Bernasconi‘s journey, from a PhD in sail modeling for Alinghi to designing foils for the 2010 campaign, paved the way for Gomboc’s evolution into Emirates Team New Zealand’s VPP tool during the era of AC72 foiling catamarans.
  • Jean-Claude Monnin is a pioneer in simulators for the America’s Cup, and joined Dan at Emirates Team New Zealand, contributing to the transformation of Gomboc into a full dynamic simulation.
  • Mark de Gids, with a focus on sailing data management at Alinghi, played a crucial role in integrating the appendage GUI (graphical user interface) into Gomboc and enhancing data viewing tools during Emirates Team New Zealand’s AC50 Bermuda campaign.
  • Davy Moyon, joining the SumToZero team during Emirates Team New Zealand’s AC36 campaign, brought expertise in sailing simulation and a strong mathematical background in physical modeling.
  • Recognizing the need for support, Lucie Léon joined SumToZero in 2019 as the first employee. Her responsibilities include technical support, developing yacht models, and collaborating with Dan on a new sail model to reduce reliance on external aero data.

With Dan, Jean-Claude, Mark, and Davy all contributing their expertise, SumToZero is dedicated to supporting its growing community of Gomboc customers and advancing the capabilities of this state-of-the-art tool in the America’s Cup and beyond.


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