Importance of True Wind

The importance of true wind in winning

The importance of true wind cannot be understated. True Wind is the sailboat’s fuel supply. Of all the functions that an instrument system produces, true wind is the most important for performance, tactics and strategy during racing.

Wind direction

is the magnetic bearing of the true wind. It lets you to keep tabs on where the wind is coming from regardless of the boat’s heading. Knowing wind direction allows you to take advantage of:

• Wind shifts
  • Tacking onto the favored board when the wind shifts is worth something like 100 seconds/mile for a 5° shift. However, tacking incurs a penalty (a boatlength or two to weather), so the potential gain must be balanced against the cost. Is the shift big enough and will it last long enough to pay off? See Break-even Tacking for more detail on this subject.
  • When the cost of tacking will not pay off, or if the tactical situation precludes it, wallying on the same tack gains to a lesser extent, and moves lateral position so when the wind shifts back, you lose less to those ahead and gain more on those behind.
  • See Sailing in the Real World for more on these subjects.
• Trend
  • The longer term wind direction provides a clue about which side of the course to go for on the next leg. OS5 provides a readout of wind trend so you can decide if it’s trending enough to change your strategy.
• Wind shear
  • Wind shear is always present, and when recognized, calms the savage breast, provides insight into sail trimming and possible future wind shifts. One of the first hurdles new instrument owners have is understanding and then using this natural phenomenon.
• Laylines & Next Leg Apparent
  • Not knowing how many minutes to the layline, or whether you’ve overstood has lost an awful lot of races, but not as many as having to short tack amongst your enemies. OS5 provides a complete and accurate Layline solution.
  • Having true wind, next leg rhumbline and a polar lets you calculate what sails to get ready, and where to put the pole (see SailPlan™ crossover chart).

For a narrative on how to use Wind Direction to get more performance out of your boat, read the Ockam U page and the various scenarios described on the real world sailing page.

True wind speed

is the ‘tachometer’ of the boat’s engine. True wind speed is one of the components in the solution of the wind triangle.

• True wind speed is a primary input for polars and targets.
• Sails are best characterized in true wind speed terms, so knowing it helps in sail selection.
• True wind along with wind direction, polars and the bearing of the next leg lets you predict next-leg apparent wind and prepare properly for sail changes after rounding.