How It Works
The sail system designed by naval architect Dick Koopmans is a free standing rig on a rotating mast.
Zoom Forward on the boom there is a rolling jib. The aim of the system was to provide a simple rig that could be easily managed by one person that has high efficiency between performance and costs. To windward this is not the best acting rig, but it is easy to repair and maintain.
It will also give relatively low forces on the existing boat. Between 60 degrees from the wind to downwind the rig is very efficient..