I am getting pretty tired of crawling around under the 1984 westy to put 
a bucket under the sink drain when camping.  I am thinking of putting 
some kind of waste water tank under the van to catch this water.  I found 
some fresh water tanks at a local marine store that look like the same 
material that the westy fresh water tanks are made of (kind of like real 
thick plastic milk carton material).  I was thinking of getting a 10-12 
gallon size tank and mounting it between the two main beams the run front 
to back under the van.  Then I would run a hose from the sink drain to 
the tank and put a drain valve in the tank, along with a small air vent.  
Has anyone tried anything like this?  Have any better ideas?? Will the 
open air vent be a problem i.e. sucking exhaust into the van?