Just thinking about how to list the constricting parameters makes my head swim. First you have limited space, because your drainage system must continually go downwards and you must arrange it around or between the grid of the trailer frame. In an Airstream, the back end tapers upwards to give it that pretty little twinkie rear, but that also limits your space. The rear of the trailer is also the most vulnerable, as the uneven "roads" you will travel, and bump your butt along, pose a threat to breaking the lowest part of your system - the drain valve.
Second, you are limited to using the only RV exit valve manufactured under the sun, which fits on a 3" pipe. Factor in two p-traps (under your sink and bathtub) that are 1-1/2" pipe diameter and then remember that you can only go up one size in pipe at a time - and that you have to have lengths of pipe between the pipe-adapters - and you run out of space quickly.
The photo below shows how snug some of the spaces can be. That flexible pipe is the only option that will make that curve. If it fails, so does my entire drainage system. The big black valve is the toilet drain, and it's a separate system. If I have to do this all over again, I'll have some re-thinking to do, as this configuration is more a construct of what I COULD do compared to what I wanted to do. It leaves much to be desired, but a working system isn't one of those desires, cuz this works!
That white flex-hose runs parallel to the black water tank and makes another curve through a hole cut into the trailer frame. I taped and zip-tied it to the frame to keep it from rubbing against anything as it travels the road.
Going through the hole cut by the previous owner, the flex hose ends in the first of many combo-adapters in line (shown below). This combo set is designed to funnel into the 3" exit pipe. What you see here (sort of flashed-out) is a flex hose clamped onto a 1" pipe that goes into a 1" bushing that couples with a 1-1/2" pipe that goes into a 1-1/2"x2" pipe-adapter that connects to a 2" right angle connector that feeds into another length of 2" pipe that is held in place by some stainless steel tape that is screwed into the bottom of the plywood subfloor.
Was that hard to read? It was hard to figure out. And even harder to do, given the space. I took this photo by sticking the camera up into the hole and pressing the button. Was happy to see a good picture. Wish I had as good a view when I was actually working on the project.
The connectors continue (below) as you recognize the 2" pipe held in place with the stainless steel tape connecting into a 3"x3"x2" T-fitting (hidden from view). One end of the T-fitting leads to the exit valve you see in the foreground. This is where I will connect the portable 10-gallon grey water tote-tank (on wheels!). The white pipe in the background is the 1-1/2" pipe from the bathroom sink. Oh yes, we had to do crazy-combo-connector-crap at least three more times.
But I'll spare you the whining and the photos from crazy-connector-combo-crap. Here's a close-up of the stainless steel tape. Whoever made this stuff was brilliant. Simply brilliant! They saved this project for me. Do you see the holes in the aluminum below the pipes? That where my arms went through while I worked from my back underneath Bessie.
Lots of leftover parts. The original design was more grandiose and elaborate. After two botched plans, I was simply satisfied with a functional system. I'm very thankful Home Depot will let me return the extra parts. The little hammerhead shark piece is made from 11 separate pieces/adapters. It is unique to Bessie.
One end of the hammerhead is seen below attached to the flexible white pipe. Whoever made this flex pipe is brilliant. Simply BRILLIANT!
Oooo, all the parts are connected and cemented. Time to seal'er up.
Other side is good too...
And now she's road worthy! Still must figure out a clever way to access the drain valves in an easy fashion, but that can wait until the weather is more agreeable, and other projects have some attention paid. I will cover this gap with a piece of aluminum prior to the first road trip. Can't risk damage to the black water tank or my precious length of flex hose!
Oh, if you could see the look on my face in this picture. Brie came home from work, took one look at me and said, "You look like you are covered in shit from head to toe."
Oh yeah? Guess how I feel?
Exhausted. I spent two full days working on this - in the mud, rain, and cold. I went to the hardware store three times to finish the project and ended up with well over $100 in extra parts from plans, and second plans, that didn't pan out. I'm so over planning and re-planning this project. But there is good news. It's over!
Guess what folks? Bessie's grey water system is street-legal. I'm coming to wash dishes at a curb near you.
