OK I actually conducted a few experiments with wing masts.

Quite a few.

I have a very nice 16 metre Marstrom carbon wingmast to play with on a boat that easily hits 20+ knots . 

Try sticking some audio cassette tape near the leading edges of both windward and leeward sides. 

Its almost impossible to get them streaming all the way up.

Don;t take my word for it try it. You really cannot get it all to trim. 

It still trims better than a non wing mast (and when you trim the mast correctly the acceleration is quite impressive) but there is still more there to be had.

As for Rutan well …. I used to know an aero guy who did (and is still doing) some interesting stuff at Edwards. He is also a sailor. 

We had this same discussion over 15 years ago. Some of the stuff he pointed out is just appearing … including the sail foot on the A class someone recently referenced here.

You can start the wing high, but you lose the “deck seal” which provides a very effective end plate … but only so long as it extends as far back as that A cat. 

I was surprised it has taken so long for someone to do this. 

Guess not everyone has a nice NASA supercomputer to play with :-)

Oh and if you gave Mr Rutan this problem you would get an answer to this problem. Probably an amazing one. I’m with Ron on this one.

The answer is still out there.

Cheers

Gary