Chris White, Mast Foil video of first boat sailing

Noticed this over on SA link posted up by phillysailor.

http://chriswhitedesigns.smugmug.com/ATLANTIC-CATAMARANS/A47MastFoil/26303240_FNw3st#!i=2211578097&k=BTDDfL4

 

so, how does one reef something like that?

Actually not sure I would call the sail a foil, it looks like a fairly conventional sail, it is just not attached at the leading edge to the mast. So it has to two large jibs. though the rigging is very unconventional to make that work.

 

The main is a foil

As I understand it, the foil is a wing with adjustable camber trailing edge. It encompasses the mast, rotates freely around it when not restrained by sailing trim. This hugely reduces stress upon the mast within, and decreases windage when the wing is allowed to rotate when compared with a traditional mast with gobs of exposed running and standing rigging. By dialing in camber and angle of attack you effectively "furl" the mainsail, or at least control power settings with lightly loaded control lines.

The two jibs have booms and roller furling, allowing greater flexibility of sail plans/sail area with the flog-prone jibs constrained at the clew. Again, reducing/minimizing flogging reduces stress on the mast and should increase reliability of gear.

If the design brief is "performance cruising catamaran" then all this is to the good. The goal is not "performance catamaran" and so ultimate speed is not the desired objective. This unique design allows one or two sailors to get a multihull up to a faster-than-average speed safely and reliably; well I guess "reliability" is the goal yet to be determined.

Notice that the daggerboards are also removed in this design. Although CW acknowledges the performance loss, the argument is that this decision reduces complexity of design and cost, there are fewer big holes in the hull, the result is more durable/less devastating in case of impact and the performance loss is manageable when combined with trim tabs on the mini-keels.

Together, you can see using this design to safely travel with 200 mile+ days regularly, and dousing the jibs at night to back off the pressure. See a squall? Furling the jibs and reducing camber is easy compared with throwing in a reef. The website speaks of being able to do all this even from within the pilothouse. Not sure how that works, but it would make a happy and safe crew!

Obviously, I'm really impressed!

There is a previous discussion on the design -- check out Response #9 for in-depth analysis of the rotating wing.
http://www.boatdesign.net/forums/boat-design/mastfoil-opinions-40487.html