A new floating dry dock, commissioned by Western Australia’s land
  and infrastructure developer LandCorp, is to become operational at the
  Australian Marine Complex (AMC) at Henderson, 23 kilometres south of 
Perth, in late 2009 and is expected to inject billions into the state’s economy.
 Built by WA shipbuilder, Strategic Marine, the floating dock features the
  latest technology including a newly developed digital memory to give it a
  fully automated capability.  
Strategic Marine’s Marketing Manager Jamie Anderson said the 99m 
  long floating dock utilises a ballast system where ballast compartments 
  throughout the dock are filled with water, or ballast, causing it to sink 15.7m
  below the water level.  
“The vessel can then be gently guided onto the dock and the ballast 
  removed to lift the vessel out of the water. Unlike some other dry dock 
  facilities, the ballast system is fully automated,” Jamie said.
  Fantech’s WA branch Systemaire, supplied 12, 560mm adjustable pitch 
  axial flow fans to pump air into the pontoons. The increasing air pressure 
  evacuates the water from the ballast tanks and the increased buoyancy
  causes the dock to rise.