America's Cup 34

[herm]

are you talking about the dagger boards?

[Howley]

Yeah that's just the daggerbord (keel) pulled up to reduce drag.

[El Matador]

Yeah that's just the daggerbord (keel) pulled up to reduce drag.

Interesting, didnm't know that was possible. Though, at the speeds they are attaining, I wonder if they taken into account the aerodinamic consequences.

[derby]

Interesting, didnm't know that was possible. Though, at the speeds they are attaining, I wonder if they taken into account the aerodinamic consequences.

http://www.multihullcompany.com/Article/Daggerboards_vs._Keels

PROS

A daggerboarded cat will sail consistently higher into the wind than a cat with keels. Typically between 5 to 7 degrees higher. This added speed and pointing ability represents a significant safety feature when cruising because it enables you to claw off a lee shore or to arrive at an upwind destination with far greater alacrity. Sometimes you cannot “run for cover” â€" you must “beat for cover.”

A daggerboarded cat, all things being equal, will sail at least 2 knots faster, on average, than a catamaran with keels simply because it isn't carrying the enormous fixed hydrodynamic drag (i.e. wetted surface) of two long and deep fixed keels. This added speed is a significant safety feature for long-range cruising. Not only are long passages cut shorter, reducing exposure to adverse weather, but should one encounter adverse weather it is much easier to either run from it or avoid it entirely with proper weather routing. A faster boat always increases one's options, and therefore increases safety, when cruising.

A daggerboarded cat typically draws 2 to 2.5 feet less water than a cat with keels. As such, the sailing grounds and potential anchorages available to a cat with daggerboards are considerably larger than those available to a keel cat.

In extremely severe seas daggerboards enable the skipper to adjust the balance of his catamaran by raising and lowering the boards. When sailing in large cross-seas you typically raise the leeward daggerboard entirely and lower the windward board half-way to prevent being tripped over by a breaking wave. A keel cat is stuck with the keels down, all the time â€" as such, there is no way to prevent the boat from “tripping over herself” in storm-force conditions.

[Statler]

the stuff quoted above is realy about cruising catamarans and the pros and cons of mini keels versus boards.. 

the boards on these boats are asymetrical... airplane wings sort of.  They are designed to keep the boat from slipping downwind, just like any daggerboard, but they are different each side.   This is coming to cruising boats too but as everything it's a trade off.   symetrical boards can be switched if one breaks while in the middle of the ocean.   

Much less drag in the air than in the water, which is why one is pulled up.

There has been some dissappointment among enthusiasts that the ac45s don't have curved boards... curved boards are being used to create much lift as well as resist leeway.  More lift on the leeward hull means more sail area can be kept up.   The ac45s also don't have canting rigs.  So these aren't cutting edge boats realy in terms of every go-fast tech bit already out there... but look like great training boats for the upcoming 72s.


I soooo want a ride.

[Statler]

dream boat.  Wife thinks, (and I have to honestly agree) it's a little on the hot end of the speed/crew/cruising continuum. 

SIG45 High Performance Catamaran Sailing Fast



notice they are being lazy and leaving both boards down.  (not an issue with symetrical daggers but these are asymetric.  No huge loss, but if racing would raise windward one.

That's a giant rotating mast in carbon. 

Hugo LeBreton, the guy who builds them, invited us to sail when we were in Europe last summer.  Still kicking myself for not scheduling the time in. 

gotta stop looking at sailing vids with all this snow out the window.   

[swampduc]

This is really interesting. I've actually been thinking about taking sailing lessons in New Orleans, partially because it looks incredibly fun, but also because "tacking", "going large", etc seem really mentally challenging.

[YellowDuck]

Messing with the kids

[Statler]

ORACLE Racing - 'Round Rangitoto on Anniversary Day

[Statler]

AC45 Sailing - Auckland 23 March 2011

[Kopfjager]

 

[herm]

exciting!

[Statler]

and people said the prestarts wouldn't be exciting.   This is going to be just crazy on the 72s.

Match Racing Pre-start action with ORACLE Racing and Artemis Racing

[Kopfjager]

Son of a pregnant dog.