Revolutionary? Yes, we think so.
The new Atlantic 47 Catamaran design continues to build on the Atlantic Cat series' innovative history with an exciting and entirely new sailing rig. The design goal was to develop the easiest to handle and safest sailplan possible for short handed cruising without sacrificing performance. That goal has been met.
The Chris White Designs MastFoil (TM) (patent pending) is a unique combination of modern rigid airfoil technology with proven soft sails. The basic concept is not new and you can see examples of rigid wings and soft sails in the current America's Cup catamarans.
However the MastFoil has some critical differences. The main difference is that the MastFoil is a small part of the overall sailplan and can rotate 360 degrees around the load bearing mast which allows it to be feathered on any point of sail and in any wind velocity. Left alone, the foil will continuously feather itself if the control is set in that mode.
Another important difference is that the foil does not carry any of the mast compression loads. This enables the foil to be lightweight, structurally simple and rotate easily around the mast.
Why eliminate the mainsail?
Most sailors agree that the mainsail, particularly the large roached, full battened mainsail combined with the aft-led-shroud, no-backstay configuration that is used in most catamarans today, is by far the most troublesome sail to hoist, reef/unreef, furl and cover. In addition, mainsails create significant safety liabilities because they cannot be easily or quickly reefed or furled when sailing downwind. In violent squalls this feature has caused more than a few capsizes. The conventional catamaran mainsail can also be somewhat risky to gybe in a blow.
For all the trouble associated with the mainsail, what do you get? Per unit of sail area, the mainsail is the least efficient sail on the boat. Sailing upwind, the mast, at the aerodynamically critical leading edge of the mainsail, robs a great deal of its power. Sailing downwind, the shrouds prevent easing the sheet enough to unstall the sail. Also the large roach area of the sail contributes to significant weather helm which slows the boat and can make steering more difficult.
At the other extreme in sail handling is the modern roller furling jib. You don't need to hoist and drop the sail every time you use it. It reefs easily on any point of sail. It furls completely in seconds. Couple these attributes with a rugged self tacking set up and there is not an easier to handle or more efficient soft sail.
In the quest for simplified handling and improved safety, let's just do the obvious. Get rid of the mainsail. And in its place substitute more jib area combined with a super efficient MastFoil.
Atlantic 47 MastFoil Advantages:
The soft sails can be reefed and furled on any point of sail and in any wind velocity. Anyone can safely handle this rig. By incorporating a Harken Rewind winch, all sails can be reefed or furled by a crewman from inside the pilothouse.
Simple and quick self tacking.
Super safe and effortless gybing.
The MastFoils add considerable drive to the sailplan despite their modest size. In stronger winds the MastFoils alone will provide enough power to sail in any direction.
The MastFoils are excellent storm sails. They create powerful drive, but minimal heeling forces because of their size and aspect ratio. The MastFoils are quiet, never flog, have very low "sheet" loads, and they can be trimmed for efficient operation with any wind direction.
The MastFoils can be easily feathered into the wind on any point of sail which makes them nearly "invisible" to the wind.
Less aerodynamic windage (drag) than a conventional mast equals less strain on the anchor which reduces the risk of dragging. The MastFoil rig will reduce the wind drag at anchor by approximately a 20%.
The dramatically simplified mast and rigging improves reliability. A MastFoil mast has less than one quarter of the number of load bearing parts of a conventional mast. Fewer parts means fewer parts to fail and consequently less risk of mast failure.
Extraordinary down wind performance. The MastFoil never stalls. In combination with soft sails, including any type of gennaker or spinnaker, the A47 is an extremely fast and easy to control flyer.
Great upwind performance. Tests indicate the MastFoil will be at least equal to a standard catamaran rig sailing upwind.
No anchor bridle required.
Anyone who has owned a ketch knows how well behaved they are at anchor with a partial mizzen sheeted flat amidships. The A47 will do essentially the same with the aft MastFoil locked on center and the forward MastFoil allowed to rotate.
All together the MastFoil rig offers an incredible combination of desirable features. We think it is the shape of things to come.
MastFoil (tm) (Patent Pending) Christopher R. White 2011