Understanding Wing Technology

Yep, Refreshingly to see the advantages.

 

Hybrid Wingsail,..
....used by Randy Smyth on Sizzors, and now on 53 cat

It would be interesting to hear some comments from previous posters to this subject thread, about this newer 'reefable wingsail',...

Several of my observations,...

Quotes from this article in Professional Boatbuilder
Professional BoatBuilder - 170 - Dec-Jan 2018 https://pbbackissues.advanced-pub.com/?issueID=170&pageID=58

 

I don't see the difference between the "hybrid wingsail" and the classical wingmast & sail combination. This publication of the Amateur Yacht Research Society from 1966 describes the wingmasts on Lady Helmsman and Gamecock C-Class catamarans, as shown in this figure.

The two new wrinkles that I see in the hybrid wingsail are the light-weight built-up construction and routing of the stays to the top of the mast so it can rotate through 360 deg, neither of which are aerodynamic in nature.

This paper describes the aerodynamic features of the wingmast/sail combination.

Large wingmasts have also been used on ocean racers, but each time the skippers come back saying "Never again!" because of the area of the mast that cannot be reefed. However, those wingmasts did not have the ability to rotate through 360 deg to allow them to be feathered with the apparent wind from any direction.

When I was landsailing, the best of the wingmast/sail combinations were competitive with the best of the rigid wingsail rigs. That may be because high lift is not important for a landyacht. The wingmasts have not been competitive with the wingsails in the C-Class catamarans since the 1970's.

 

@Tom Speer
The difference with this hybrid wingsail is that it can be REEFED.


And of course it can also fully feather by rotating the 'fixed foil section' a full 360 degrees.

The rotation axis is also very important to adjust the balance force developed by the rig. Quoted by Randy in that ProBoat article, "this wing has only a fraction of the sheet load. That's why I was able to trim it so quickly in those gusts."......"the wing exerts about 40% less load at the mainsheet. ....the old rig needed a seven-part purchase, this one only a 4-part purchase"