The holding tanks on the bus are very important. I need a fresh water and a grey water tank. I am installing a tankless water heater, so my showers will only be limited by my own will to conserve, and the capacity of the bus holding tanks. Water tank capacity will also dictate the length of time that I can boondock. If I’m off the grid, water is severely limited. Water is likely to be the first thing that I will run out of while out on the road. So, to extend my ability to stay off the grid for as long as possible, I needed a high water-holding capacity. Therefore, I had two tanks custom-sized to fill the spaces where they will be mounted as efficiently as possible, for maximum storage. Both hold 75 gallons.

As I stated in the beginning of this project, I don’t know how to weld. It’s not that I can’t get stuff welded if I need it. I totally can because I have friends with skills. However, when I am thinking about how to solve problems, I usually want to figure out how to do it myself. So, due to my lack of welding skills, this is how I mounted my tanks.

I’ve already had a bunch of haters tell me that they don’t trust my system, or that I did it wrong, or that I’m stupid. So, if that’s how you feel about this, save your hate for my future video titled, “Shit! My tanks fell off my bus!” In the mean time, This seems to be an extremely solid option. I did pull-ups and subjected my supports to various kinds of abuse to feel them out. But, to better understand my reasoning for this design, let’s do some quick math. Disclaimer: I am not an engineer, but I think I play one on the internet. Take this assessment with a grain of salt. I’m sure than any engineer would look at this logic and laugh in my face….but I don’t know enough to know why. Anyway, each strut is held up by 6 bolts, and there are 5 struts per tank. That’s 30 bolts holding each tank to the steel floor of the bus. The bolts are designed for holding pieces of metal together, and are 3/8 inch in diameter. So, the 35 bolts are not going to lose the struts. Here’s a link to some technical specs of superstrut. If I’m reading that right, the pullout strength of the 1/2 inch rod and nuts that I used is 2000 lbs. Each strut supports two of these; one for each side of the tank. So, in theory, if two rods were splitting an equal load, that load could top out at 4000 lbs. There are a total of 10 rods hanging on 5 struts, holding up 5 supports, and the weight of the tank. Non-reversing nuts and washers are used to lock everything in place and keep the bolts and nuts from backing out or getting loose. 1 gallon of water weighs 8.35lbs. My 75 gallon tanks will weigh 626.25lbs when topped off, plus the weight of the tanks…which I estimate is around 35lbs, but I’m pretty strong, so… let’s just say 675lbs to be safe. As I use water, that weight will be split between my tanks, but there will be times when one tank or the other is nearly full to the brim while I am in motion. Even so, the roughly 675lbs of water and tank is split between 5 individual struts, so each strut only needs to hold 135lbs, give or take. Water will slosh around, so let’s just say 200lbs per strut. I weigh about 200lbs. One strut could carry my full weight while I tried to bounce around and rip it off the bus, without any problems. It didn’t budge. It made me feel bad about myself and buy a gym membership. So, will this system hold my tanks? I am confident that it will.

Compared to other systems I’ve seen people use with success, I am quite confident! I’ve seen people online using ratchet straps from harbor freight to cradle their tanks under the bus by essentially strapping them to the under-frame. I’ve seen people tie it up under there with a couple chains. I’ve seen people build boxes out of untreated OSB and 2x4s and bolt them to the frame. My system doesn’t compromise the frame, or even touch it, and it distributes the load between 5 supports and 30 points of contact to the steel floor of the bus. But I didn’t weld it! Let me eat my words of confidence when the system fails.

P.S. I know my math is wrong in the video. This post’s math is better.