Skin discoloration can be due to changes in melanin. Melanin is a skin pigment that gives color to the skin. Changes in melanin can also cause skin to be patchy. Treatment for skin discoloration includes using topical treatments.
Winglets increase an aircraft's operating efficiency by reducing what is called induced drag at the tips of the wings. An aircraft's wing is shaped to generate negative pressure on the upper surface and positive pressure on the lower surface as the aircraft moves forward.
The lateral wings of a winged keel are usually of moderate aspect ratio, that uses a nearly horizontal foil, the  wing , at the bottom to provide additional span. Note that, contrary to classic configuration, the keel is upside down under the hull (the root chord is smaller than the tip (bottom) chord.inged keels are generally found on high performance sailboats, if they are not prohibited by class rules. They are only of benefit for yachts sailing upwind where stability and the ability to produce side force are important and if the draft is limited by the class rule.