The Dotan system has been around for years...but never seems to catch on. I believe there are heavy compared to most stock setups.

By co-incidence, I just sailed on a boat yesterday using the Dotan setup...they were put on the first production run Weta 14' trimarans. While everything seemed fine on this boat...the latest boats have an upgraded rudder setup that looks identical to the Australian High Performance Catamaran system I once fitted on my old Tornado...can be seen on the Capricorn F18.