Gardner,

  The two would definitely need to be independent; otherwise, instead of a graceful foil generating lift and directing airflow onto the said, the mast would just be a big slab out there creating turbulence.

  However, as with standard rotating masts, you can find a relatively happy medium that will work for many wind angles.  With a noticeable part of the wing aft of the center of rotation, and with the sail itself pulling on the wing's trailing edge, the mast will automatically want to rotate into a reasonable angle. 

  If you limit the rotation with a rotation limiter, you'll be set for just about everything except a tight beat and a run.   And even in those cases, you'll still probably be more efficient than a standard D-section aluminum stayed mast.  If your rotation limiter were adjustable, you'd have even more chances for optimization.  I pretty much leave mine set on tight-medium and adjust it only if I refuse to let someone else out-tack me downwind.

  Of course, if you did want to race, and eek out every possible eighth-knot from the boat, you'd need a set of blocks to fine-tune the mast angle relative to the boom on all points.  But that's a lot of work.

  However, now you need to strong sets of bearings: one for the mast to rotate freely from the boat, one for the vang-less boom to rotate freely from the mast.  That's more complexity, more expense.

---

  If you're serious about keeping expenses down, another option is the swing-wing soft wing sail described by Kim and Rudolph.  One mast, no boom, no rotating bearings anywhere, no sail track.  I know you're plans haven't revolved around this rig, but I thought I'd mention it again since you've been focused on cost lately.  Unless you're going with a schooner rig (where I'm not sure the swing wing would work), it would be hard to beat in terms of price.

        - Mike

 
 
Gardner Pomper wrote:

 

I am under the impression that with a wingmast, you need to rotate the
boom independently of the mast, so that the wing is at a steeper angle
to the wind than the sail. Am I correct in this?

If so, that seems like you could no longer have the boom fixed to the
mast and use the mainsheet to adjust the angle of attack. Wouldn't you
need extra lines to trim the wing seperately from the sail, especially
in light air? If so, that seems like a major disadvantage for a
cruising boat.

Thanks for any help clearing up my confusion.

- Gardner