C-Class Catamaran - The Cogito Project
Steve Clark and Duncan MacLane sailing Cogito in 2004.
Posted on Thursday, January 10th. Look for next posting on Wednesday, January 23rd.
In March of 2004 I was fortunate enough to start working for Steve Clark in preparation for the International C-Class Catamaran Championship. The event was scheduled for the following September. I wrote a posting several weeks ago where I described my first sail on a Tornado as feeling like I was on a spaceship. I had that feeling again the first time I sailed on a C-Class, except that, the feeling of sailing on a spaceship did not really go away the more time I spent on the boat. Modern C-Class cats, such as
Length – 25 feet
Beam – 14 feet
Sail Area – 300 square feet
Crew – 2
Trapeze – 2
Lars Guck and I racing Patient Lady VI.
For a quick comparison, a C-Class is 5 feet longer than a Tornado and 4 feet wider. A Tornado has only 34 square feet more upwind sail area, and the boats are raced with about the same sized crew. Note that there is NO minimum C-Class weight. Cogito weighs in at about 375 pounds; this is only 35 heavier pounds than the Tornado class minimum.
The result is an unbelievable sailing machine. A C-Class can fly a hull in just about 4 knots, which is unheard of. But more amazing than that is the boat’s ability to sail through lulls. The boat is so light, and its sail plan and blades are so efficient that once Cogito is flying a hull, it can sail through patches of almost no wind at all.
Steve and Duncan demonstrating the speed of the C-Class in extremely light air.
However, the first thing I noticed when I got on board was not how light the boat was, but how the sail did not luff. It made these loud, creaking noises in stead. As you probably know, modern C-Class cats have a hard sail, also known as a wing sail. Cogito’s wing has three distinct ‘elements’ which rotate on a series of hinges in a manner similar to that in which the aft flaps of an airplane wing move. The manipulation of these elements allows the sailors to induce shape into the wing, or, trim the sails. When the boat is stopped, rather than hearing a sail luff, one hears creaking, and an occasional bang, as each of the elements swings back and forth. I can try and explain further about how a C-Class wing is trimmed, but I think I would be unsuccessful. Almost every C-Class wing is different, and my explanation would be useless without several drawings which I do not have (I can try and draw for you myself, but you would probably just laugh at me).
The upwind VMG of the C-Class is almost unmatchable, it sails higher and faster than almost anything you have ever seen. But more surprising is how smooth and quiet the ride is. The boat is almost noiseless, just one narrow hull knifing through the water, with two crew, 14 feet away from that point, flying high above the water.
Lars and I, sailing Patient Lady VI with experimental lifting foils
Brief History of the C-Class
The first C-Class race took place in 1961. In 1962, Van Alan Clark (Steve’s father), had an entry in the competition. That year the victor was Hellcat I, sporting an innovative idea – cross beams. Previously, most catamarans had a solid deck connecting the hulls. Hellcat’s cross beams allowed for a much lighter platform, and brought home the C-Class crown as a result.
It is unfortunate that C-Class events have not received more attention over the years, as the sailing and design talent involved in the projects is usually top-notch. Prior to designing the Olympic Tornado, Reg White designed several C-Class Cats. Van Alan Clark, whose contributions to the sport both on and off the water are too numerous to mention here, built the World’s first boat with a canting keel, the Red Herring. The 6 person team Steve put together to build Cogito included David Hubbard and Duncan MacLane. Both David and Duncan were on the design team for the catamaran which defended the
Of course, the C-Class is now most widely known because of the wing sails which all boats use. The first wing sail appeared at a C-Class championship in 1974 on Miss Nylex, and it was made of spruce and balsa. Miss Nylex won the title that year, but was defeated by a soft sail boat (Aquarius V) the following year, mostly because Aquarius V was lighter. However, the future was clear, and C-Class engineers have been trying to find ways to make both their wings, and platforms lighter and more efficient ever since.
Most C-Class participants have been either American, British, or Australian, but challenges have also come from
Steve and Duncan, sailing upwind in Cogito.
After Cogito won the C-Class title handily in 1996, there were no challenges until 2004. Cogito won handily again, with Patient Lady VI finishing second, an Australian entry finishing 3rd, and a British entry finishing 4th. Just after the 2004 regatta, a Canadian named Fred Eaton purchased Patient Lady VI to use as a model for his own project. Fred built Alpha and raced against
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I’ve been playing around with canted sails and like the advantages. What is the thinking about this in the C class?
How do these cats do against a Tornado off the wind when the T has the asym up?
Comment by John — August 5, 2008 @ 6:22 pm
Stan, you and your group are the best in the world
Thanks and best regards from Garda lake
Katia
Comment by Katia — September 7, 2008 @ 9:41 am
Good post. The easy part is to set up a blog, the hard part is to make it interesting so people will visit it…Well done!
Comment by plaisir du luxe — October 26, 2009 @ 4:31 am
It would have been great if Lee Griswold could have seen BMW Oracle obliterate Alinghi this weekend. Lee was one of the pioneers that conceived of the wing sail back in the ’70s during the heyday of the Little America’s Cup. He was a great guy and a fine engineer. He loved C Class cats, or any cat for that matter, and although he passed over 20 years ago, and even though the America’s Cup is won by a tri, somehow I think he’s smiling!
Comment by Jim Kendrick — February 12, 2010 @ 8:42 pm
thank you for informaiton about cogito.
can i ask what material was used ?
i mean carbon used here was woven or knitted?
could you pleas email me?
Comment by JOO — March 9, 2010 @ 3:47 am
wow Duncan Mc was my sailing instructor at Roton Pt. Tony DiM was Commadore. Grew up watching PL1 through PL4; competition with RED ROO, YANKEE FLYER , MISS NYLEX , SYMATAR, even got to sail BULLROAR D class . These guys where my mentors as their inspiration helped me become a junior and senior national champ in aqua-cat competition back then, and some success in tornado.Nice to see it still alive in legacy .Thanks for post ….. many memories
Comment by Mark Hansen — March 25, 2010 @ 7:54 pm
An excellent but too short discussion!
Steve Clark gave a long slide show at Bokeelia Florida last weekend at the A-class Regatta, attended also by Oliver and Lars Guck sailing borrowed boats (they both did well).
I missed the polars for PL and Cogito in teh slide show, but have seen them for Fred Eaton’s winning boat and OffYerRocker, the foil boat: these latter figures were published in May 2009 CYRS.
Are polars available for Cogito (and the new C-boat soon ready to splash?) Not to be OCS (over early), but inquiring minds want to know!
Comment by DAve Carlson — March 30, 2010 @ 10:55 am
Aloha Steve Clark,Fred Easton, Stan and other “C” flight-instructors, Yes, indeed- Let us contiue to promote the beauty and “power-grace” of these delightfull “platforms” 25′x 14′x 300 sq. ft. Maybe we could suggest a future C-Class configuration with a Bi-Plane “Free-Standing” rig- (2) x 150 sq. Ft. Already Ben Hall (c/o Hall Spars fame) with his “Solid-Wing-Sail” on his A-Class Cat has done most of the “homework”- Could we beat the Miss Nylex’s, Cogito’s, Alph’s to the weather-mark; can we most efficiently and effortlessly maintain the Faster-than-the-Wind Glide and sail/foil down with deeper tacking-angles by way of the developed Apparent-Wind. The other possible Concept would be 300 sq. ft. Kite-Foil configuration. Keep-up the Good-News, Imua Ka Kou/ Ganbarre Nei iruka-san.
Comment by J.J. Iruka Saitoh-Car'ee — April 12, 2010 @ 7:24 am