A fin stabilizer is for the roll-stabilizing of a watercraft in motion, at anchor, or at zero speed, including a shaft on which a stabilizing fin is disposed. The shaft is drivable by a drive unit for changing at least one angle of attack of the stabilizing fin in the water. A cross-sectional geometry of the stabilizing fin is changeable by at least one actuator, and the stabilizing fin forms a closed surface geometry. Due to the hydraulically effective cross-sectional geometry of the stabilizing fin, which cross-sectional geometry is largely changeable by at least one actuator, a significantly increased energy efficiency of the fin stabilizer results with a simultaneously improved stabilizing effect of the fin stabilizer, in particular with respect to suppressing rolling movements of the watercraft.

A device for simultaneously and progressively varying the camber and the angle of attack of a hydrodynamic and aerodynamic profile of a wing, the latter being able to adopt multiple positions including a position at rest, the said profile at rest being in a plane, the device having a wing with a profile having a leading edge at the front and a trailing edge at the rear, a seat arranged in the upper part of the profile of the wing connected at one of its ends to the front upper part of the profile by a first pivot, and at its other end to a lever by a connection point, a lever connected to the rear upper part of the profile by a second pivot, and that at rest, a seat and at least one lever are aligned or substantially aligned along the same axis and are included in the same plane as the profile.