Chris White Designs
5 Smith's Way
Chris White Designs
5 Smith's Way
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 "
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Notes on this specification:
The Atlantic 47 MastFoil (tm) (patent pending) Catamaran can be tailored to meet the requirements of the owner.
Hulls, decks, bulkheads and pilothouse are constructed from vacuum bagged Epoxy-Vinylester resin and high performance glass fiber laminate cored with PVC foam.
All exterior surfaces are spray painted with Alexseal (TM) linear polyurethane coating.
Interior joinerwork and floorboards are foam cored panels to provide rigidity at low weight.
Propulsion and Steering
Twin Nannidiesel/Kubota N4-30 (30 HP) diesel saildrive engines
Instrument panels with tachometer and engine warning lights and alarms.
Primary and secondary fuel filters.
Dual “ZF Micro Commander” electronic single lever engine controls mounted at both the cockpit helm station and pilothouse inside helm.
Flex-O-Fold Bronze geared folding propellers
Rudder blades are fiberglass composite, high performance hydrofoil section with solid rudder stocks turning in low friction bushings.
Mast and Booms
Double tapered carbon fiber masts, each fitted with lightweight carbon fiber composite MastFoils.
Masts are deck stepped, Dynex-Dux Dyneema shrouds
Masthead running lights, masthead VHF, wind instruments installed
MastFoil rotation controls, jib sheets and reefing controls are all led to cockpit.
Carbon fiber composite Jib Booms for self tacking
Both self tacking jibs equipped with Harken Unit 2E electric reefing/furler.
Composite forward crossbeam and compression beam.
Fusion moulded sails by Quantum Sails. UV cover on foot and leech with padded furling luff, Antal clew block
Type 316 1x19 SS wire rope headstay inside furler.
13mm Dynex Dux (ultra low stretch Dyneema) shrouds
Dyneema halyards and control lines. Low stretch Dacron sheets and vangs.
Harken "Radial" self tailing winches:
Two, Harken #46 Electric Radial winch for jib outhaul/sheet
Two, Harken #46 Radial winch for vangs and gennaker
One, Harken # 40 Radial winch for halyards
Two, Anderson line drivers, MastFoil control
Harken ball bearing blocks are standard equipment.
Spinlock rope clutches
Fins with adjustable flap
Two cored glass fiber fins moulded to hull bottoms, each with a trailing edge adjustable flap.
Electric actuator flap controls with angle indicators.
Each hull has a collision bulkhead separating the hull forepeak from the accommodation space.
In event of collision damage to the forward part of the hull water will not flood the hull past the collision bulkhead.
In addition, in the event of capsize the collision bulkhead is designed to keep the hull forepeak dry allowing a safe habitation place for the crew.
The starboard hull incorporates an "escape hatch" on the inboard hull side adjacent to the collision bulkhead which allows easy access into the boat should capsize occur.
(4) Solar Panels, 140 watt output each
12-volt circuit breaker panel with voltage and amp meters.
House battery bank, 600amps hour deep cycle gel-battery ( Ultracell UCG200 x 3 ).
Victron battery monitor
Separate engine start batteries
LED interior lights
Resolux full spectrum fluorescent lights in galley, work areas and engine rooms
LED red night lighting within the pilotho