poor-man's grey tank

[Chuck]

what do you think of this? my '73 has no factory grey tank....you can only use a blue-boy if there's a dump station close by. (i.e. at a campground! no good for boon-docking, as you'd never be able to lift the thing up when its time to leave). I was wondering if I might be able to carry a blue-boy on my spare tire carrier, which is mounted under the front end of the trailer, just behind the a-frame. I've never used the thing, and I don't have a spare tire...don't really need one w/ a double axle trailer. I've never even taken a close look at this mechanism. Thismorning, I stuck my head under there and took a look, and the belly skin has been removed around this entire section of frame...I assume to accomodate a tire. the bracket doesn't extend that far below the level of the belly, and I guess the space between the frame members is needed for this. The the bottom of the plywood floor is covered with what looks like the same material that is used for the interior skin, so its not exposed to the elements.

So, there's a big space there....9" tall from the top of the frame to the spare tire rack. there's about 3 feet from front to back; I didn't measure the total width available, but the brackets on the spare tire rack are about 24" apart. why can't I mount a tank right there? I was tninking of trying it w/ a blue-boy..if it works out, I could remove the spare tire rack, and permanently install a bigger grey tank...so what if it hangs down below the skin-level a little bit? I could run a piece of pex tubing (lightweight, flexible) to the rear of the trailer, attached to the belly using pipe hangers, (either riveted or screwed to the skin), and just connect it to the "tail pipe" via the 3/4 garden hose connection on the sewer pipe cap. water will find its way to the tank, because the highest point in the tank will be lower than the lowest drain in the trailer. I could put a ball-valve right there to keep it from draining back when hooking up to a sewer connection...and even attach a siphon pump to drain the tank.
this would be easier than removing the belly pan, re-routing all sorts of internal plumbing....and I'm under the impression that there isn't alot of space back there between the frame members...the axles are close by, too.

crazy idea?

[thenewkid64]

Chuck,

It would work. I would not tow it for many miles with the tank full, as it will effect the tounge weight and will cause handling issues.

With that said, try these on for size. If you tap into the gray line above the connection to the main drain and ran the pipe thru the inner cabinets, etc and put it thru the floor under the kitchen cabinet you would almost be on top of the tank. You could also tie into the gey vent stack this way.

Or you could relocate the kitchen sink drain line to the floor T it off and run the new end to the tank, this makes that line a 2 way street. Both of these solutions would assume you have the sewer cap in place to hold the water back at the lowest point.

Benifits: One is that the pipe would be heated, saving the freeze up issues. The second is that the tank could be equipped with a "normal" dump valve and be emptied rapidly. Third you can always still use a full hook up site and have the water go into the campground drain. The best of all, no exter moving parts to remember to open or close to make it work. Sewer cap on and you are using the internal tank. Offf and it drains.

Drawbacks. Having to use a bigger bucket when removing the sewer cap to catch the stored grey water. But you do that now anyway, right?

[Chuck]

Well..don't know if that would work, as my shower is right on the floor. pipe would have to run underneath the floor for the length of the trailer, if I'm following you correctly. Now, if I were going to go to the trouble of dropping the belly pan, etc, etc....I suppose I could just put the tank in the back. But I'm under the impression that there isn't alot of room back there in between the frame rails, and where the axles come in to play. I also don't see how the tank could use the same pipe to both fill and drain, because it would have to enter up high or on top of the tank.

I was just thinking...if a tank were to go in the front, half the work is already done.

the blue-boy I have already has a dump-valve on the side, so if I could make it fit...I could use that to drain, as well, although, I was thinking that it might be possible to use siphon action to empty it, too. I'm not planning on any winter camping in this thing, so freezing isn't a big worry. I just want something for the occasional summer dry-camping outing....like the rally coming up: no hookups, no dump station....no grey water dumping. old trailer = "metal tent", w/o an integral grey tank.
Of course, my first stop after leaving would be the nearest dump station. But I wonder how much that would actually affect the stability of the trailer while towing....I'd be starting off w/ a full fresh tank, which is right behind the proposed grey tank. some of that water will wind up in the black tank, waaaay in the back; the rest, in the grey. It wouldn't be any more weight than if I were to sit on the couch while under way. which, I know is illegal, but would it really be that detrimental? knowwhatImean?

oops; the pic didn't come through right. connect a hose from the bottom of the poop-chute to the pex tubing....

[thenewkid64]

Chuck,

What I was suggesting would require you to have the pipe running above the floor. But even in your drawing the water will need to reach almost the same level (floor) to enter the tank. I was trying to save the extra work of opening up the pan with the suggestion of lowering the sink drain pipe from the kitchen. It runs in a downhill slope towards the rear of the coach. Once lowered it would act as the pipe to run into the tank. This assumes that the poop chute cap is on and it has filled with some water too. All you are doing is creating a place for the water to "back up" to other than the shower.

I envision that when showering in either setup you will be standing in a bit of water while it works it's way thru the system.

[Chuck]

but if the pipe was above the floor, you couldn't connect it to the shower, because the shower is ON the floor (not raised up like newer models) . A guy I know did something (I think) like what you're describing, but only for the sink in the kitchen. so he has to use a blue tank for the shower. I don't know how he drains the grey tank, now that I think of it.

I could also do like in my drawing, but connect the pex to the blue tank's dump valve via a bayonet cap w/ the threaded hose fitting, just like what goes on the back poop-chute. It would be entering the tank at the bottom, but should still push the water up into the tank, since the top of the tank is still lower than the lowest drain. (I have one of those big 4-wheeler blue-boys that has a standard 3" dump valve on the side). I could dump quickly from the front, or slowly from the rear....or just not use it at all if a full hookup is available.

I do envision a slow-draining shower, in any case....that's ok, as long as it drains!

[uwe]

Chuck,

I think your idea is a good one, although the shower drain will give you hurdles to jump. Literally.
Take an afternoon, remove the belly skin from under the rear bumper forwad, to the proximity of the rear axle. It's just a few million rivets.
You will see where there is room for a permanent grey tank, and how the plumbing can be ran quite easily. The dump tube will have to be modified. You run the 3in down to near the rear wheel, and then connect the 1.5 to it, so it would drain into the same hose when on hookups.
You might be able to fit 2 10gal tanks down there, and conect them with 1.5in hose, which would give you 20gal of grey, enough for a weekend with no hookups.
If you want, I'll crawl underneath and take some pics for you. PM your e-mail if you're interested to see how they fitted mine.
I am thinking if you're going to spend time and effort and money, why not do it for real.

[Chuck]

yeah, I'd love to see the pics of yours, if you have them.

My thought was to do this with a minimum of effort, time, and money....I already spent 150 bucks on this fancy blue-boy. might as well use it....if I can attach it to the trailer. my proposal will cost about 10 bucks worth of pex tubing and a couple of fittings. not too tough to take. But yeah, it would be nice to have it done "right", too.

[uwe]

Chuck,

You can still use the blue boy, chances are that the 15 or 20 gal tank you can fit under the floor would fill quickly, and for a longer stay, the blue boy would still be needed, i guess.
I will take some pics for you and send them tomorrow.

[Chuck]

Thanks for those pics, Uwe. I have a much better idea of a real permanent solution would work now.

Here's a pic of the space I'm talking about, in case anyone is wondering. Its hard to get a good image of this area, as its dark, and you can't get the camera very far away. But here you can see that the belly skin has been removed in this section, and the frame member is exposed. It is about 4" tall. hanging from that is the alluminum spare tire rack, hinged at the bottom. what you can't see here is how the forward end of this curves up and connects to the a-frame, just behind the propane bottles, and is held in place by a pin. from the horizontal arms of the rack to the bottom of the floor is about 9" high. Those "wings" or pins that stick up from the sides are there to keep a tire from sliding off the rack. a small blue-boy will fit in there, no problem, but my big one probably won't without some modification. Wouldn't be difficult to cobble up something that'll hold the larger tank in place, I don't think. I could use the existing hangars, and keep it hinged, so that if nothing else, it could be used just as a carrying rack/storage for the auxiliary tank.

[Chuck]

So I had my boss play around w/ his 3-d cadd program that we've been trying out. gave him the frame dimensions, and the tank dimensions, to see if the thing would fit. You can't really see it from this angle, but there is a bit of slop-space in there.