, raw boat speed through the water is a deceptive metric. To win, you must execute a superior Velocity Made Good (VMG). Unlike simple speed, VMG measures progress directly toward the windward or leeward mark. A boat can scream at 50 knots, but if it sails too far off the wind, its VMG suffers. We focus on this performance metric because it isolates the yacht's aerodynamic and hydrodynamic capabilities from tactical errors. The data shows that even small gains in VMG median values translate into massive distance leads over a full race leg.
Deciphering Frequency Distribution Plots
Performance analysis relies on heavy filtering to extract truth from noise. We remove non-foiling periods, tacks, and jibes to analyze straight-line efficiency. The resulting frequency distribution plots reveal the boat's 'sweet spot.' A thick dashed line represents the median performance, while the surrounding clusters show how consistently a crew maintains peak speed. When you see a team's distribution 'blob' shifting up the page, they are demonstrating superior drag efficiency or better power management in that specific wind range.
Visualising AC75 Performance: What the graphs mean!
The Anatomy of a High-Performance Maneuver
Winning is often decided in the 40-second window surrounding a tack or jibe. Modern analysis centers on how a boat carries speed into the eye of the wind.
might show higher entry speed but struggle with the 'build' on the new tack. We look for 'meters lost' during these maneuvers to decide if a tactical shift is worth the physical cost of the turn.
Tactical Implications of Leeway and Wind Angles
Beyond speed, we monitor leeway—the sideways drift of the yacht. Teams like
use foil flaps and cant angles to minimize this, sometimes achieving 'negative leeway' where the boat effectively crabs to windward. Understanding these nuances allows coaches to determine if a team is sailing in a gust or simply out-designing the competition through superior lift-to-drag ratios.
