Rob,

    I think you have seen this already:

http://www.onesails.com/wingsails.php

My question is would the round section mast be easier/cheaper to build than the normal D section like you have been doing?  Notice the diameter is the same all the way up, could you make this by going over a pvc pipe mandrel or such?  I think it would be hard to keep the carbon in line though.  Maybe an open mold would be better?

Thanks,

Jerry Barth