The 400 has a great storage space in the aft bilge compartment, but you must be careful where to store items, so not to interfere with the rudder function. The rudder position indicators are also very fragile. All this stuff is very open to damage or jamming if something should slide into the wrong place.
My solution was to build a box from "Starboard" plastic lumber, to cover the mechanisms, and provide a shelf with fiddles to store tool boxes or other stuff on. The bottom section of the box is three sided to allow the wires and hoses to run out the back side, while the top has a higher fiddle to keep objects from falling behind the box. Two latches hold the cover securely while allowing quick easy access if required. Be sure to provide a cutout on the starboard side for the steering ram piston.
Now I can store loose items without fear of jamming the rudder or damaging the rudder position sensors.