Wayne.B wrote:
On Tue, 19 Dec 2006 14:21:17 GMT, "Roger Long"
wrote:

Still, it's a big, messy, and dangerous job. I'd focus on that instead of
the results.

That's very true and an important point. I know people who have tried
similar mods and been very disappointed.

The whole wing keel concept was really applicable only to the old
style 12 meter Americas Cup boats because of a design quirk in the
rating rule.

This is nonsense. It may be true that the particular design used in
the 12's wouldn't be appropriate for a cruiser, but the basic concept
is valid and quite useful. Simply put, the water that flows under the
tip of the keel reduces the effectiveness of the bottom foot or so of
the keel. The wing keel prevents this flow and keeps the last foot of
the keel effective. This permits reducing the draft by roughly a foot
in many cases. In addition, the ballasted wings are essentially a
bulb. It should be noted that the primary purpose is to reduce draft;
the deep keel will normally be more effective overall.

The quirk in the 12 meter rule was a draft limit of about 8.8 feet
(16% of WL plus .5 meter) so the wing allowed Lexcen to get better
upwind performance out of that draft. The story gets a bit more
complicated, but that's the most important part.

As others have pointed out, the best bet for a cruising
boat is something called a scheel keel, or possibly a bulb.

The Scheel Keel is certainly a neat design - it has the same design
goals as listed above for the wing keel, but it has less drag (or is
it more lift?).



http://www.cs.brown.edu/people/jfh/p...AQ/node16.html

This is a pretty simplistic view of the topic.