bearflag
Inventor/Fabricator
- Joined
- May 10, 2010
- Posts
- 227
- Reaction score
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- Location
- Thousand Oaks, California
The Chris White Designs MastFoil™ (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 large 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 sail plan 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 if the control is set in that mode. Without this critical ability to feather on any heading, a rigid airfoil would typically not be suitable for use on a cruising boat. 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™.
...
However the MastFoil has some critical differences. The main difference is that the MastFoil is a small part of the overall sail plan 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 if the control is set in that mode. Without this critical ability to feather on any heading, a rigid airfoil would typically not be suitable for use on a cruising boat. 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™.
...
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