The Advantages of Winged Keels

by : Leaftech

In 1983, the Australian team manning the boat Australia II shocked the sailing world by taking the year's competition for America's cup. Up until that year, the world's most prestigious yacht regatta had returned year after year to the United States. So what was it that gave the Aussies the advantage that year? Most experts point to the innovation of the winged keel the Australian yacht had been equipped with. In fact, this theory has proved so strong that today many sailing boat owners are interested in using the wing type keel for their own vessels. Let's take a look at the advantages that the winged keel added to the Australian team's boat, and what it can add to yours.

The horizontal foil

The part of the keel that is referred to as the wing is actual a horizontal foil adapted to fit a traditional shoal keel. There are several advantages to this adaptation, and they include:

A decrease of draft without decreasing efficiency. Traditional shoal keels make it harder to steer a boat properly, but with the wing effect this type of keel is much easier to manoeuvre.
The aspect ratio is doubled. Aspect ratio refers to the ability of the keel to resist pressure from the water, dividing in a flowing manner along the sides of the boat. The higher the number, the greater the glide.
Additional downward lift is provided, and this makes the boat much more stable (it sits more comfortably in the water).

The greatest advantage of the winged keel is when one is sailing upwind. The greater stability and the side force produced by the horizontal foil allow a racing boat an advantage in conditions that are not ideal to the sail force.

Of course, the advantages of the winged keel are only obvious under the right conditions, and they may not be for every vessel. Lighter, non-racing craft, for example, may find that the advantages this type of keel represents do not transfer under ideal racing situations.

Nevertheless, if you are into long voyage sailing in deep water a winged keel is virtually guaranteed to give you an advantage in terms of both speed and stability. That's what won the Australians the Cup more than two decades ago, and it remains the strong selling point of winged keels to this day.