Abstract: An apparatus for stabilizing a vessel to drastically reduce the rolling and/or pitching of floating vessels, platforms, or the like. At least one stabilizer is suspended by a bridle secured from a vessel so as to be submerged in the water. The stabilizer is formed having a pair of hingedly connected wing members, so-called with regard to their shape which is formed by a sequence of longitudinal sections associated by dimension and angle to provide a differential convexity over their breadth. This wing shape actuates rapid configural changes in the stabilizer so that the wing members assume an open span resisting bridle tension, or a folded swiftly sinking phase when the bridle is not tensioned. The wing shape is adjustable in camber and aspect ratio to retain optimal efficiency at any scale.