The new falcon

"Maltese Falcon"

Occasionally someone comes up with a design for a yacht which pushes the yachting envelope.

I used to work for Tom Perkins on the Herreshoff Schooner named Mariette of 1915.  Tom is a Venture Capitalist in San Francisco, and for the last two or so years, has been concentrating on his latest sailing project, “Maltese Falcon” designed by Ken Freivokh and Gerry Dijkstra.

Based on a 35 year old German rig design called a Dynarig, wind tunnel and computer tests show the yacht will be capable of reaching 15 – 18 knots upwind, with an apparent wind angle of 25 – 28 degrees!  That’s about the norm for a modern sloop, but a square-rigged – 3 masted clipper ship?

So nice to see someone is thinking outside of the box.

Comments

[Brooks Moses]

That is an interesting design, indeed!

What's the advantage of using a square rig in this case, rather than the usual arrangements? Anything other than "it looks cool"? (Or is it a matter of scaling, that the usual arrangements don't work for something this large?)

[david]

Certainly scalability is an issue here. The number of crew required will definitely be reduced. An Americas Cup boat has 17 crew, the Falcon will exceed that, but not by much. And the usual arrangements do work, Mirabella V is almost as big, but with a conventional sloop rig.

[Richard Tomlinson]

Prandtl theory has a lot to do with the design of the sail form. Prandtl, a German physicist, demonstrated that elliptical wing forms optimised lift/drag ratio in incompressible flow (hence the wingshape on the famous WWII Spitfire). If you think of the sails of a boat as a large vertical wing, you will understand why the dynarig offers some serious aerodynamic advantages over other rig shapes.

[Brooks Moses]

Ah, indeed, of course! And those sail shapes also look like they're influenced by another result from wing theory, too -- that a long narrow wing has less drag than a short wide wing.

[Richard Tomlinson]

Strictly speaking, a wing with a high aspect ratio has a high lift/drag ratio. But you're correct that you can draw a lot of conclusions about how a boat will sail by applying wing theory to the sail-plan. A boat with a high aspect ratio rig will go upwind well because of its high lift/drag ratio, but will also require a more skilled helmsman, whereas a squat low-aspect ratio rig will not go upwind so well, but will be more forgiving to a lazy helmsman (hence their use on cruising boats).

You can also draw similar conclusions about a boat by looking at the underwater lines. If you think of the keel as an underwater wing, you can deduce how well the boat will go upwind, and how easy or difficult it will be to helm efficiently.

When you combine both a very high aspect ratio rig with a very high aspect ratio underwater fin (as on say an America's Cup boat) things start to get very interesting for the helmsman as he has to keep two wings at a point of maximum lift/drag, which (because of their high aspect ratio) is also very close to their stall point. This is why America's Cup boats have two steering wheels - one controls the rudder and hence the angle of attack of the rig, and the other wheel controls a trim-tab on the back of the underwater fin to optimise lift/drag without stalling it.

[brian eiland]

I've followed this DynaRig development for a long time, particularly since the Falcon project began.

Result? My latest Dynarig motorsailing catamaran:

[Sailing Greece]

Great design