My MK IV A cat had a first genration of the system you saw on the Marstrom. The downhaul line ran through a carbon tube and exited behind the rear beam to pop-up cleat. A buungee raised the rudder when the line was released. Later versions that the Marstroms have been using run the carbon tube to just behind the daggerboard trunk and exit through a turning block to the opposite side. So you can raise or lower the rudder from the high side.