The competitive sailboat racing industry is constantly looking for innovative methods of increasing boat speed. A ballasted keel accounts for roughly 80% of the total weight of a maxi-class racing yacht. A mechanism that replaces a portion of the ballasted keel at a reduced weight could have substantial effects on the performance of the boat. With this in mind SEM Technology designed and built a Bidirectional Dynamic Hydrofoil (BDH). This device used hydrofoil technology to provide lateral lift and a righting moment when the yacht is in motion. The scope of this project was limited to proving that the conceptual technology of the BDH was viable and did not include analysis of the interactions between the BDH and the sailboat. The Bidirectional Dynamic Hydrofoil project successfully provided lift in two directions and proved the viability of this technology.
Pictured on the right is a drawing of the inner core of the BDH structure. A cam shaft actuated three ribs in order to change the shape of the BDH and the direction of lift. These ribs provided the correct hydrofoil shape and a reinforced-silicon sheath wrapped over them to create a smooth surface. Pictured below is the team standing behind the BDH (with a black sheath on it) attached to the ‘qualitative test rig’. Right to left: Gaelen Krause, Ross Coleman, Nick Daniel and Jeff Crawford.
