Arrangement to vary the drag on a sailboat, has two half-keels with ballast, both of which can be moved just like the wings of a butterfly by a strap mounted on their rotation drum

摘要

The device consists of two half keels (1,2) having ballast, which can be lifted from the navigation position to the horizontal position, by opening like the wings of a butterfly, under the hull of the boat by means of a strap (8) which is placed around the keels rotation axis (6) and driven by another axis (13) engaged with a motor drum (14). The selection of the drums together or separately in one direction or other, offers the possibility to reduce the drag on the water or again to move the ballast (3,4) under the boat. The position of the ballast in the position D allows it to rest on the dry dock without any support.