Prediction methods for sailing yachts in the early design phase

Recent sailing yacht projects have highlighted the importance of getting involved in the design process as early as possible. And given the ever-shrinking amount of time available for design development, it is vital to be as efficient as possible. Here we describe some of the studies that can be done in an early phase, including tools available to conduct those studies.

Over the years design challenges for just about any sailing yacht has remained the same:

• Wide versus narrow;
• The volume distribution and profile outline over the length of the vessel;
• Proper distribution of the side force over the length to get the right yaw balance and loading of the appendages and hull, at various heel and trim conditions;
• Various other shape variations, such as bow and stern sections;
• Design rule restrictions.

Then there are those custom challenges. A particular one is how to efficiently generate side force on very large draught restricted designs. This is a challenge because, when the allowed draught reduces, the lift production of the hull becomes less efficient due to a lower aspect ratio. At the same time, these very large yachts also typicallyhave strict requirements for comfort suchthat the alignment and positioning of appendages becomes important to avoid trailing vortices passing through the propeller disc as much as possible.

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