All the components of Hydraflex hydraulic steering systems are made specifically for
the marine environment, using materials and working processes which offer long life and
safety for the most extreme conditions. 
  How the system works
  
  Under normal operating conditions, a turn of the steering wheel will send the oil from the
  helm unit into one of the two connecting hydraulic lines. The oil will be pumped into one
  of the chambers of the cylinder and either extend or retract the cylinder rod, depending
  on the steering wheel rotation. The fluid going out from the other chamber of the cylinder
  is returned to the helm unit via the other hydraulic line.
  There are only two basic components for all the Hydraflex hydraulic steering 
  systems. These are the helm unit and the cylinder, connected by nylon or 
  copper tubing. The helm unit consists of both a hydraulic pump section and a 
  valve assembly. The valve
  assembly prevents outgoing fluid from returning along the same line, isolates each
  steering station, locks the rudder and eliminates rudder  feedback  to the
  helm. The cylinders are double acting and may be balanced or unbalanced ( the rod extends
  through only one end of the cylinder ).