TECH TALK - BOW CHINE

Alinghi’s bow features a chine (step on the surface) about one-third of the way up from the skeg.

This design seems intended to deflect water away from the hull surface when a bow wave is present. A bow wave is created when the skeg is in contact with the water, and it can propagate upwards to cover a large portion of the bow. The chine redirects the water traveling upward away from the hull surface, reducing wetted area and subsequently decreasing drag. This feature is similar to the spray rails found on some foils.

This design can be advantageous when skimming though waves, which are common in Barcelona. In addition, it can be useful during takeoff by reducing wetted area when the water level drops below the chine. The chine’s narrow width and the aft taper indicates that its aerodynamic impact is small when the bow is not in contact with the water.

On the downside, the chine will create additional drag when fully submerged.