New Zealanders Bill Buckley and Charles St. Clair-Brown believe they have created the fastest and most innovative monohull in the world. Just as pedigrees count for a lot in the horse business, the 24-carat lineage of the new 100-foot carbon-fiber canting-keeled sloop is certainly impressive. Designed by Greg Elliott and Clay Oliver, both alumni of the team that created the current holder of the transatlantic record, Mari Cha IV, the silver-hulled yacht that was lowered into Auckland waters in mid-February looks as though it may be able to deliver the goods and give Mari Cha a run in this spring’s transatlantic race.
The hull has a relatively narrow waterline beam and flairs quite dramatically outward as it moves toward the sheerline. Below the waterline the hull is not unlike a very large surf ski. While the narrow keel and bulb don’t appear to be radical departures from the norm, there is one major innovation. The lower part of the fin can retract into the upper part, reducing draft as well as drag. Forward of the keel is a retractable canard with a trim tab.
“We thought hard about what would be the best length for the yacht,” says co-owner St.Clair-Brown, “and we concluded that an overall length of 100 feet would be ideal. It allows us to compete for line honors in all super-maxi regattas as well as the Sydney Hobart Race, which is an important event for us. The only rules we have brought to the table with this project have been speed and safety.”
Add to those very sophisticated engineering, particularly with regard to the retractable canting keel, the construction, and the onboard systems. Canting keels are nothing new, and neither is the concept behind them. Shifting ballast to windward keeps the yacht more upright. And since it is sailing with minimum wetted surface, it can, with maximum sail power, achieve maximum potential speed. That means planing across the oceans even in the most turbulent conditions.
Because the keel has been engineered to cant to 50 degrees—most of the units out there go only to 40—the projected maximum heel angle for the yacht is calculated to be 15 degrees or less (as opposed to 20 degrees for a yacht with a noncanting keel). “If you fix the righting moment,” says Elliott, “you fix the degree of heel, and this puts the science of sailing into a completely new mode.”
To prevent a massive failure of the canting system, the yacht has been fitted with a backup system consisting of two hydraulic pumps that are driven by belts off the main engine. Each pump is capable of running all the hydraulics on board. Two rams, built with a safety margin of four, power the keel’s canting mechanism. The canting mechanism can also be operated manually.
But the magic here is the keel’s ability to be retracted into itself to reduce draft and drag. While most retracting and lifting keels are fixed—they run up through a housing that often extends to the top of the interior space—Buckley and his engineers have come up with something different. The heart of the design is a cast hollow fin with a retracting mechanism housed inside it. The lower section of the fin can be extended or retracted into the housing simply by pushing a button in the cockpit. This can be done even when the keel is in a canted position.
In addition, the canard forward of the keel is also retractable and has a trim tab on the trailing edge. “Although you could rotate the canard to create the necessary lift to windward,” says Elliott, “you’re still dealing with a symmetrical foil. When you add a trim tab, you create an asymmetrical foil, and that produces far more lift.”
During a shakedown sail in light air on Auckland’s Hauraki Gulf under full main and a #3 headsail, I was impressed that the yacht could do over 5 knots in only 3 knots of breeze. When the wind rose to 5 knots, we were closing in on an honest 10 knots. It took only about 10 seconds to shift the keel all the way from one side to the other. In other runs off Auckland, the yacht has been clocked at over 25 knots in 20 knots of breeze.
The flush deck forward of the long, narrow cockpit is clear of all impediments, including cleats, to avoid fouled lines. All running rigging passes under the deck through tunnels and exits into the forward end of the cockpit, where the lines are secured by jam cleats. Fouled lines in the tunnels are easily cleared via hatches in the overhead of the main saloon. The yacht’s aft end is nearly all cockpit, with dual helm stations located in the middle of the cockpit, not unlike an America’s Cup Class yacht. Although the crew will communicate via headsets, having the action take place around the helmsman does shorten his reaction time. A low coachroof allows a clean view of the entire forward deck along with unrestricted visibility around the entire yacht.
Two large Harken carbon-fiber winches control the headsails, and a third winch farther forward in the cockpit handles the mainsheet. Headsails are raised and clamped into a locking mechanism at the head, and then the tack is pulled down and is tensioned with a hydraulic arm controlled from the cockpit.
The 128-foot double-spreader wing mast is deck-mounted on a bearing, and the mast’s rotation is controlled by sheets that lead to the cockpit; the section can be oriented to an angle of 60 degrees on either tack. The section design permits a lower-aspect-ratio rig with a very efficient full-roach mainsail. The rotating mast also allows headsails to be sheeted to narrow angles. All standing rigging is lightweight PBO fiber.
Things below are pretty Spartan, and nothing has been overlooked when it comes to saving weight. Most of the aft section of the interior is open; 18 carbon-fiber pipeberths accommodate the racing crew, and one communal locker aft holds their gear. There is enough space in the engine room to maneuver around the six-cylinder diesel. Fuel can be transferred between tanks to help trim when racing.
Directly ahead of the engine room, the nav station has a chart table and surrounding paneling made of carbon. Navigation and wind data are fed to two waterproof wireless computers mounted near the helm station in the cockpit. A 6-Kw generator and watermaker are located in a separate compartment aft of the nav station. To further reduce weight, the generator can be unplugged and taken ashore. The focus on weight reduction is also reflected in the finish, or lack of it, below. The only surfaces that have been painted—in high-gloss off-white—are in the main saloon, where orange suede cushions line the settees along the sides of the saloon. A cabinet on centerline in the saloon houses a refrigerator, freezer, and drink container. All other areas have been left bare, in the natural black carbon finish, and three sleek windows in the low coachroof help make the saloon light and airy. All the joinery is in carbon. Even the kitchen sink and the toilet bowl are carbon with a clear-coat finish. A 4-foot-square piece of flooring just 1/2 pinch thick was so light I could pick it up with two fingers.
The owner’s cabin is forward of the main saloon; it too is furnished with carbon-fiber pipeberths. The housing for the retracting canard is farther forward, and doors on either side of the housing can be folded back flush against the housing to allow sails to be moved forward or aft. A large sliding hatch forward provides plenty of room to get sails on or off the foredeck in a hurry.
The transatlantic race crew includes George Hendy, a Whitbread veteran and shore manager for the last British America’s Cup challenger, and veteran navigator Mike Quilter. But if this experienced crew is going to be able to give the well-traveled Mari Cha any kind of competition, they’ll have to learn in a relatively short amount oftime how the yacht handles over a full range of conditions. One sign that they’re serious about going fast over turbulent water is that Olympic boardsailing gold medalist Bruce Kendall will also be on board. He will, no doubt, be concentrating on the wind and waves coming from astern and figuring out how to catch the next wave and fly with it.
David Woodley covers the New Zealand waterfront for SAIL.
Designer: Greg Elliott and Clay Oliver, Elliott Marine, Box 34-576, Birkenhead, Auckland, New Zealand; 011-649-480-9792; www.elliott-marine.com
Construction: Hull, deck, mast, boom, and all interior floors and joinery are carbon fiber with carbon reinforcing beams running longitudinally down each side of the hull’s interior to increase strength.
Builder: Cookson Boat Builders, 59 Hillside Road, Glenfield, Auckland, New Zealand; 011-649-444-9515; www.cooksonboats.com
Sail area (100% foretriangle)
4,558 sq ft
240-hp Steyer diesel
Sail area-displ. ratio