OzOne wrote:
Doug, IIRC, The biggest advantage Benny achieved with his wing was as
a 'cheater'.

Oh, I dunno... Dennis Conner and the New York YC certainly
thought it was cheating. Everybody else thought it was cool.

AmCup yachts rating formula took draft and keel weight into
consideration and Benny worked out that he could place the extra
weight in a wing arrangement on a shorter keel and gan measurement
advantages in other areas including sailplan.

There is also a limit on draft in the 12-Meter rule. One of
the 'problems' with the wing is that it is deeper when
heeled, and Australia 2 was protested on those grounds.


When heeled, the wing still gave the depth required for good 'grip'
uphill while giving reduced draft downhill.
Of cousre there were the other advantages, but a lot of work was
required to reduce drag from the possibility of generating an extra
tip vortex on the keel.

As I understand it, the way the tip vortex reduction works
is that the two tips generate counteracting vortices. There
is more turbulent flow, but less loss of differential
pressure from leeward (high pressure) to windward (low
pressure) and less energy transferred into the water. "Less
energy transfer" is a fancy way of saying less drag.


I know there are a couple of excellent studies online, but I just
can't recall them this evening.


Here's a pretty good one, although this begins far beyond
where mass-produced wing keels leave off.

Back to the original:
The international committee in charge of approving the
measurement & rating of 12-Meters had the power to stop
Australia 2 before letting her enter a single race... the
question of how to measure the girth at hull stations,
whether to include the wings in the draft, etc etc...
complex issue, but they decided to let it be decided on the
water.

The funny thing is that Dennis Conner was cheating too, he
had an illegal mast and had Liberty measured in two
different configurations, so effectively she was two
different boats. He whined & bitched about being cheated out
of the Cup, but the truth is he sailed an awesome series and
almost won anyway. If they had been smart, the Race
Committee could have enforced their own draft rule by
putting at least part of the course in water that was deep
enough for Liberty's conventional keel but not quite for
Australia 2's wings (which were very large, something like
18' span IIRC).

BTW I never did understand the name change with Bob Miller.
He was definitely an outstanding genius and a great sailor.

Fresh Breezes- Doug King