Originally Posted by Seaworthy Lass
I thought the advantage of the winged keel in that series of races was that it allowed greater sail area or waterline length while still complying with the formula for the 12m rule
. Nothing to do with the depth
of the water
they were racing
If the winged keel gave no advantage, then it must have been Aussie John Bertrand's superior skill over Dennis Conner
As I understand it the wing improved hydrodynamic properties slightly and increased the boat's stiffness slightly by lowering the center of gravity of the ballast without increasing draft (which would have changed the rating).
The net result was a 1/10 to 1/4 percent improvement in boat speed depending on exact conditions at any given moment. At the highest levels of racing this is an advantage worth the cost and there are no ancillary penalties.
Beyond the highest levels of racing differences in crew skill and sailing effort vastly overwhelm the effects of the wings.
Also wing keels have suffered in their implementation on production boats. The biggest problem has been using them on shoal draft models. While the lower center of gravity of a wing keel might be able to compensate for 2-4" of less draft, more typically shoal draft boats are 8-18" shallower.
Early production versions were also rather cookie cutter
. Once a manufacturer had determined a shape for their wings, that was the shape that was used on all their boats scaling it up and down to suit. In reality for most craft wings need to be designed for that particular vessel, the interaction between the wings and the fin and even the hull
is very complex. In the '80's and early '90's the theoretical and computational facilities just weren't weren't available to optimize wings to the actual hull
it was being attached to, remember the Intel 486 was introduced in 1989, it ran at 16MHz and cost $3-4K. The alternatives were renting
mainframe time or using a modeler and tank time to physically test different versions.
Also once a manufacturer had settled on a shape for use on all their boats, it could be trademarked so other manufacturer's were required to develop their own shapes.
More recently the trend in racing boats for very deep, high aspect keels with bulbs on the bottom has made it easier to put relatively cookie cutter
wings on them. Being very deep there is a lot less interaction between the wing and hull and the fins for such keels have become very similar. Also the theoretical understanding of what is going on is much better and there are vastly better computational resources available so it is much easier to use a boilerplate fin, bulb and wings and tweak the details slightly to optimize for each particular boat.
For cruising boats this is not the case more conventional fins still need to be used so cookie cutter wings are a lot harder to use. But my understanding is that bulbs provide some of the effects of a wing but are sturdier in a grounding and don't catch lines and weeds as much so there might be a little movement in this direction currently. We'll see over the next 5-10yr.