Sailing Boat Design


The design technologies in ACT are based on those developed through the America's Cup projects.

Performance design technology

The design technologies in ACT are based on the experiences in the design by CFD, tank testing, problem solutions, 2 boat testing and analysis, sail analysis and etc in the America's Cup projects in different teams.
We design sailing boats by scientific approach using CFD[*1] and VPP[*2] since yacht design needs to consider different balanced conditions at the same time. We have the longest design experience by CFD started in 1993. Also the design cannot be finalized only in science and the knowledge in design experiences and the feedback from actual sailing performance are important factors for better design.
The dynamic balance in sailing is an important and inevitable item to consider for design. The CFD and VPP are the strong tool to clarify the balance. We always continue to improve our design to fit each sailing style and design condition by looking at the actual sailing performance.

One of the CFD codes we use is the SYPPS which can cope with dynamic balance in pitch, heave and heel directions. Many tank testing results have showed its good accuracy within the error of 1%. The technology was developed for the 2000 America's Cup and dramatically reduced the design cycle time at the time. The JPN44 and 52 in IACC class were created by use of this code. Recently we have introduced the new CFD code, Fine/Marine by NUMECA, and can analyze the detail flow around a hull with appendages. The simulations by the multiple CFD codes can improve the overall accuracy.
Other CFD codes for appendages or sails are also applied to evaluate performance.
We use two simplified VPPs, ORC VPP and WinDesign, and one original VPP_SLTM. VPP_SLTM uses tank test data and CFD results and solves 4 equations inlcuding yaw moment balance which is critical to actual performance. The sail model can treat the sail trims changing the main and jib camber, twist and traveler.

Comparisons of VPP_SLTM results and sailing data(above:main trim below:heel angle)

Performance analysis technology

The sailing data and the sail shape analysis are very effective to improve the boat performance. However, it is also very difficult to do them very accurately due to data variations by unstable winds and instrument calibration problems. Then we can provide our original data analysis techniques with special software which can extract good data and effectively analyze boat performance. This technology has been improved through the America's Cup projects. The details are as follows,

1. Logging Data Analysis

The boat performance is analyzed by using logging data. This can be more effective for 2 boat testing employing telemetry system. The results can be viewed on board during testing in real time.

2. Sail Shape Analysis

The sail photos taken during sailing can be transformed into 3D shapes and the shape can be analyzed by using CFD to clarify the performance with the logging data.

3. VPP Analysis

The VPP models for each boat can be tuned with the logging data, and the VPP can predict the potential boat performance.

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