thumb|right|250px|Winged keel of [[Australia II]]
The winged keel is a sailboat keel layout first fitted on the 12-metre class yacht Australia II, 1983 America's Cup winner.
Design
This layout was adopted by Ben Lexcen, designer of Australia II. Although Ben Lexcen "had tried the winged keel idea before", there is conjecture that it was computed and designed by Dutch aerodynamicist Peter van Oossanen at the Wageningen towing tank (Netherlands Ship Model Bassin).
Wings
The lateral wings of Australia II are of moderate aspect ratio, forming a nearly horizontal foil, the "wing", at the bottom to provide additional effective span, in the same way as the winglets on an aircraft.
</references>