Bart wrote:

What is the purpose of this rig?

It is not a rotating mast!

http://www.yachtworld.com/core/listi...photo_name=rig

http://www.yachtworld.com/core/listi...d=65591&ur l=

Good grief! The environmentalists will be complaining that it's a
hazard to migrating birds, what a cluster-****. Bet it's a whole heap
o'fun tuning that mess.

Cheers
Marty