Scamp Greywater Tank Mounting

[Peter L]

A few months ago I sought some advice here on retrofitting a shower into a toilet-only 13" Scamp. Thanks to all your help the project is nearly finished and I'm very happy with the results. (I'll do a picture-post over the holidays to show y'all!)

That was phase A of the project. Phase B is to install the factory-ordered gray tank. For those not familiar - the tank has a 26 gal capacity and goes under the floorboard at the very rear of the trailer (under the dinette).
Plumbing : 26 Gallon Grey Water Tank
(For anyone looking for similar tanks - this appears to be the manufacturer Replacement RV Parts & Fender Skirts - AC Shrouds & more - IconDirect.com)

My initial inclination is to drill holes around the flange and simply attach it to the dinette floorboard using wood screws. However, it's not lost on me that a worst-case fully loaded 26 gal tank would weigh over 200lb. Double that for acceleration riding over a pothole, and add a safety factor or two - now we're talking some serious vertical loading.

Which brings me to my question - Could I bother anyone to take a peek under their gray-tank equipped Scamp and see how the tank is attached to the trailer?

Things I'm curious about:
- If it IS just wood screws - how many and what size approximately?
- Any bolts that go through the floor? If so, how are the bolt heads concealed inside the trailer, if at all?
- Any steel bands/brackets that attach directly to the frame?
- Is the tank mounted flush against the plywood? Any visible padding?

Now, I'm not suggesting I plan to travel any significant distance with 26 gallons of graywater in the tank (or that it's even safe to do so - given what that much rear-end weight would do to the tongue weight) - but I hope to set things up so that if I had to go a little out of the way to find a dump station, I wouldn't risk finding my gray tank unceremoniously deposited on the highway!

Thanks!

[Eddie Longest]

Peter
I Installed a grey water tank in a S-13 last June. Scamp, I think uses pan head #10 X 3/4 screws installed about 6-8" apart around the flange no bolts through floor. They install two straps between the angle iron floor support behind the tank to the rear of the drop floor steel support.
First thing is check the tank bay for screws that may be sticking through the floor. Either remove and replace with shorter screws or grind them off. I made a template out of cardboard to figure where to drill the drain input and vent line. I predrilled the screw holes in the flange and used #12 x 3/4 stainless screws. I used hex head screws with a top hat head. (PK or duct screws) I installed my screws about 4" apart.
For strapping I used wide steel band straps for lumber. I got mine off of some rail road ties.
The big issue on a S-13 is the drain pipe clearance in relation to the road. I would not be too concerned about fall and even if you have leave a little water in the tank. Once it glued together it is what it is. I blocked and strapped the drain pipe to the frame behind the tire and to the floor behind the dump valve near the outlet. I ended up replacing the axle with a 0 degree axle to get a 2.5" lift.
Send me a P.M. if you have questions.
Eddie

[peterh]

We're adding a gray tank to our Surfside, which wasn't designed for a gray tank. It's installed in much the same way our Scamp's gray is installed, just a little smaller (21 gallons). Part of the planning process included moving one frame crossmember and adding a second one so the tank could be supported front and back.

The tank is supported by steel hardware/plumber's tape. On the Scamp, the front end of the straps are screwed into the step-down frame member, and the back strap is screwed into the "L" shaped frame cross member just behind the tank, similar to what we did front and back here.

Our tank is held in place by three straps.


Scamp uses self-tapping sheet metal screws. I chose to use small, #10 carriage bolts, which required I not only drill the holes for the bolts, but square the holes off with a file. After cutting the holes, I dabbed them with Rustoleum frame paint, then pounded the bolts in.


With the straps secured on the far side, I pulled the plumber's tape so it would snugly fit the tank, put a nut and serrated washer on, then cut the bolt shorter so it wouldn't run into the step-down floor area.


Scamp also puts some packing material between the tank and tape, which might have been a darn good idea. I don't think our tank has enough wiggle-room for it to become a problem, but I'll check our install after a few thousand miles to look for signs the tape is cutting into the tank.

[Peter L]

Thanks Eddie and PeterH.

Based on your input, looks like my best bet is to go with with a ring of #12 self tapping slotted hex sheet metal screws around the tank flange, with a couple of pipe hanger straps for secondary support.

The numbers in this chart (see table 3)
http://www.grabberman.eu/Media/TechnicalData/452.pdf
give me a good degree of confidence that expected vertical forces of a fully loaded tank can be borne safely.

I've got a follow up question - could anyone with a shower-equipped Scamp describe for me path that the plumbing takes to get from the front of the trailer where the bathroom drain is to the gray tank at the back? I understand that the drain pump is mounted upside down directly under the shower. To go from the pump to the gray tank - I'm thinking of a flexible rubber hose that goes back up inside the trailer, through underside of the sink/counter assembly to the dinette area where the greywater inlet is. The alternative is to plumb under the trailer the entire way (exposing the hose to road grime and debris) - I want to avoid this if possible.

[Eddie Longest]

Peter
The pump and filter mount below the shower pan floor and they use an additional piece of plumbing strap to hold the pump to the floor. Scamp uses EMT (conduit clamps) to hold the drain hose to the floor and to the frame. The drain hose is routed from the pump to the outside of the drivers side frame rail. The hose is held to the frame rail with three or four clamps. There is a double stack piece of frame tube near the axle. The hose goes through this tube and comes out behind the axle. The hose then snakes to under rear bay of the center dinette floor. The hose is then attached to the floor bottom and makes a U turn and enters the rear of the tank. If you have a shower tank there will be a drain fitting in the rear of the tank.
I used self tapping steel (non stainless) screws to attach the clamps to the frame. The same head as holding the tank. ( The stainless screws will snap off. Also pre-drill the holes.)
Scamp places a piece of metal in front of the pump which drops down from the upper floor for a little protection. I think Floyd welded up a little cage to protect the pump.
I highly recommend the lumber strapping to hold the tank, also paint your straps to prevent rust.
Eddie
Re read thread
I would not worry about road grime on the outside of the hose. The inside of the hose gets much more nasty than the outside will ever get. Also good info. on screws in plywood.