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On Dec 3, 11:56 am, "Charles Momsen" wrote:
Why doesn't a keel achieve maximum efficiency with a leeway angle of 0
degrees?


Who says it doesn't?

I would say that a keel which makes ZERO leeway is highly efficient...
super-efficient.... preternaturally efficient!


~A leeway angle of zero degrees means the flow comes head on at the keel.
Since keels are symettric, the net lift is zero and the drag is a quantity
greater than zero. L/D = 0 in that case.

What is a typical angle for maximum efficiency?


Depends on the typical aspect ratio and typical foil section.

Many boats make 3~5 degrees leeway when hard on the wind.

~Correct


Does a catamaran have maximum efficiency at 0 degrees?


No of course not.

~Rethink the question with the new information about leeway angle.

Why?

Because it's a catamaran, not an iceboat.

~~Iceboats and catamarans work on very similar principles in this example.

~

Fresh Breezes- Doug King