I suppose the plumbing is different on the Ariel and Commander.
Here is the area underneath the "galley." The galley is just a cabinet with a sink. I pulled that off the boat for refinishing.
A molded fiberglass tube leads out of the boat. On top of that is a short length of black hose (the one I can't get off).
The green hose leads from the water tank to the sink water pump.