The boost effect

The essentials

In the routing table, an asterisk after the name of a sail, for example “Code 0*”, announces the boost effect.

With automatic sails, VR does not change sail as soon as the new one becomes faster: it waits until the boat exceeds the reference speed by 1.4% (the overlap factor, 1.4% by default, a value supplied with the boat’s polar). Between the moment the reference speed is reached and the moment this factor is exceeded, the boat still sails with the old sail, but at the speed of the new one. This is a temporary gain: the boost effect.

What to do if you see the asterisk:

• change the wind angle (TWA) of the order slightly to leave this zone; for example, if the table shows “TWA 110° Code 0*”, set the order to 108°;
• if several consecutive sails carry the asterisk, it may be better to turn the automatic sails off temporarily in VR, to avoid a series of sail changes caused by small wind variations.

Going further

How it works. Between two sails, there is a wind speed (TWS) from which the new sail is faster than the old one. At that threshold, the boat reaches a reference speed. The sail change only happens when the speed exceeds this reference multiplied by 1.014 (the default value). During the interval, the boat benefits from the boost.

Why automatic sails are advantageous. The boost effect exists only with automatic sails; with manual sails, there is no boost. In some cases, turning the automatic sails off remains preferable (see above).

In the application. The routing table writes the sail name in italics, with the asterisk, when the routing detects this effect on the row. See also Reading an order row for the stretches where the order editor asks you to turn the automatic sails off.