This tacking proa was built by Mark Thomas Hansen in Mission Beach, Queensland Australia. Mark has kindly given permission for me to share these photos. I think the photos are fairly self explanatory. Anyone tempted to contact Mark can put his name into facebook. More information can be found on Mark's blog, Motumarksworld.blogspot.com.au LINK
There are also three youtube videos of this boat sailing, just put Mark's name in and do a search
A bit more information
Boat weighs approx 600kg
Boat takes approximately 90 minutes to setup (a fraction long, possibly due to stay support bars on starboard side)
Boat tacks very, very well
Boat points from 140 to 285 degrees, assume this means can point to within 70 degrees of the wind