Change of speed with real wind fixed

Adjusting the sails in case of speed change #

We consider a steady current wind and a steady true wind. What happens when a dinghy accelerates and when it slows down?

• Acceleration : wind speed (vv) that increases
• Slowing down: wind speed (vv) that decreases

Close-up speed #

Downwind point of sail #

The faster you go downwind, the weaker the apparent wind.

The Speed Polar #

In order to illustrate this, here is the speed polar of a Laser solo. This curve is constructed by plotting the boat’s speed according to the angle to the true wind. These are the theoretical maximum speed values, and reaching them will depend on the trainee’s level.

The maximum speed is obtained for 105°-110° for 30 kts of wind. Overall, the fastest point of sail is the right full.

The boat does not come up any better than 30° from the wind and downwind its speed is about 60% of the true wind.