Another OBW Project

[Miller315]

Hello all. Been lurking for quite some time, getting great ideas and information. Some of you guys are absolutely amazing in your skills.
For me, I am a moderate hunter, fisher, camper, boater. Not crazy into any, but more than some I guess. I live in the PNW on the coast. Lots of opportunities for outdoor activities. I have a 2008 F350 diesel with Leer canopy. I currently have a Alpenlite camper and bayliner ski boat. The camper is all but sold right now. We are going back to tenting it. Love the camper, but hard to justify financially for the amount of use it gets. We have 2 kids and the camper isn't big enough for the whole family, plus friends, plus the dog. We end up taking a tent anyway. I prefer( like a lot of you) to do my own projects and build vs buy.
So here is my project, I want to put on an on board water system. Here is my thought, please give me any input, ideas, suggestions, and whether or not you think this will even work.
I want to put a 7' long 4" PVC pipe under the cab of the truck. Parallel to the step/ running board. I have looked up under there and it looks like I can strap the pipe to the cab supports. I have a 12 rv style on demand water pump( I already use it for a portable sink system when hunting). I am thinking mounting one on each side, under the cab. One will be slightly lower than the other, and both will be slightly sloped to flow water out. I am thinking running a hose to the bed and making some sort of quick connect on the side. My thought is that with 4" pipe I will be just under 1 gallon per foot. With water weighing 8.35 # per gallon I will be less than 60 per side, and less than 150 # all together. With a F350 this weight should be nothing.
I have a used rv supply store near me that has cheap supplies. I thought about getting a rv water fill connection to fill and vent as well.
Any input would be great. Thanks

 

[Ducky's Dad]

I don't have a SuperDuty, but I suspect you have a ton of space under that thing. Mine is a Dodge 2500 and I think I could siamese a pair of 4" pipes on each frame rail if I didn't already have aux batteries mounted under there. You could probably fit a 6" pipe nicely, but then it would be more susceptible to damage. I think ABS pipe is stronger than PVC (more impact resistant) and still suitable for potable water, but confirm that before you buy the pipe. If you run pipes on each frame rail, include a way to isolate the two tanks (ball valve) so that if one is damaged or springs a leak you can avoid losing the water in the other tank. I put 6" screw caps on the ends of my pipes so that I could get in there with a scrub brush when necessary. Another reason for the screw caps is to control water surge in the unbaffled tanks. Best thing for this application is plastic wiffle balls, baseball size for 4" pipe and softball size for 6" pipe. Tanker trucks and some boat tanks use a version of wiffles on steroids to control surge, but it may not be an issue on an F350 with the water down low. Big pipe joints in PVC or ABS are difficult to execute, so build a jig or have something really solid to push against and have a helper with you when you make up the joints. It takes a lot of force to twist and seat big fittings, so use a slow glue and plenty of it. You want squeeze out around the entire outer circumference of each joint. Pipe is cheap, fittings are expensive, so minimize the number of fittings in your design. If you use PVC, paint it to prolong the life of the plastic. I wouldn't worry about sloping the tanks, because the truck will seldom be level in the boonies. When I need to drain mine, I just park with one front wheel on a rock.

And now, the easy but expensive solution. Since you have a diesel with a long wheelbase, think about buying an auxiliary fuel tank and plumbing it for water. I couldn't find one for my Dodge, but I'm pretty sure they are readily available for the F350. Try Titan Tanks.

 

[Miller315]

Thanks for the response. The water won't be for drinking as much as for wash off. Cleaning salmon, or after getting a deer, or clam digging, my biggest need is for clean up.
I thought about going for bigger pipe, but like you said, bigger chance of damage. I would never have thought about the wiffle ball trick. Or the screw caps to be able to clean out. Great info for me to start considering when I start this project.

 

[98dango]

Growing up in the Pacific Northwest I would also look at a light duty shield. The gravel will fly I have broken more rock lights than I care to count just driving on the road. Any thing to deflect a rock aluminum or plastic such as a cutting board would be great and not *** alot of weight.

 

[Miller315]

Growing up in the Pacific Northwest I would also look at a light duty shield. The gravel will fly I have broken more rock lights than I care to count just driving on the road. Any thing to deflect a rock aluminum or plastic such as a cutting board would be great and not *** alot of weight.

Great point. Sticks and rocks can wreak havoc.

 

[Ducky's Dad]

There are lots of different schedules of PVC pipe available, besides just the commonly available Schd 40 and 80. If you want PVC and impact resistance, look at Class 200 pipe. As wall thickness goes up, so does weight (duh!), but it can also slightly reduce the water capacity per foot.

From http://www.diffen.com/difference/ABS_vs_PVC

Strength
ABS piping has a higher impact strength than PVC, especially at lower temperatures. However, ABS can deform under sun exposure.
Durability
ABS is highly durable with high impact strength. PVC is less durable, as it is designed to be flexible and softer than usual plastics.

ABS is cheaper than PVC, but has a narrower range of fittings. Heavier pipe may be better than a stone shield.

 

[AFBronco235]

And now, the easy but expensive solution. Since you have a diesel with a long wheelbase, think about buying an auxiliary fuel tank and plumbing it for water. I couldn't find one for my Dodge, but I'm pretty sure they are readily available for the F350. Try Titan Tanks.

You don't want to use an aux fuel tank for water simply because they're not made for it. They're not going to be scrubbed clean and kept clean during manufacturing. There'll be all kinds of contamination inside those things, mainly oil residue, welding spatter, metal shavings and who knows what else clinging to the insides of those tanks.

On a similar note though, most farm stores can get potable water tanks pretty easily. Basically the same things as a tank for a field sprayer, only black instead of clear white. Not as cheap as or complicated as what you're wanting to build, but pretty simple and easy to clean. Most come molded with transportation needs in mind. They also come ready plumbed for any kind of use you can think of. I think the smallest I've seen is 20 gal, but you'd probably want something in the 50 gal range. If you see a store that sells plastic water storage tanks for field and sprayer use, chances are they can get what you need. Just make sure you specify that you want a black potable water tank.

Your idea will work, if you want to keep your tanks hidden, but I just feel like its unnecessarily complicated. That being said, I hope you post pics of how you go about it.

 

[98dango]

417 pounds of water is alot of added weight. You also want to remember if you are in cold climate that driving you will have cold air moving at a constant 60 mile an hour wind to super chill the water.

 

[Ducky's Dad]

You don't want to use an aux fuel tank for water simply because they're not made for it. They're not going to be scrubbed clean and kept clean during manufacturing. There'll be all kinds of contamination inside those things, mainly oil residue, welding spatter, metal shavings and who knows what else clinging to the insides of those tanks.

No weld spatter or metal shavings in a Titan Tank because they are plastic, just like the factory tanks on many new trucks. Easy to flush with water and Simple Green, then more water, but OP says it's not for drinking water so not a big issue. Advantages include high capacity, internal baffling, secure mounting, and no need to fabricate. Disadvantage is high cost. OP could use a plastic fluid transfer tank in the bed of the truck, but the camper shell creates some issues with that idea. If 10-20 gallons is enough, then pipe tanks are probably the way to go. There are hundreds of pre-fab plastic tanks available, but the trick is finding one that fits your situation.

 

[Ducky's Dad]

if you are in cold climate that driving you will have cold air moving at a constant 60 mile an hour wind to super chill the water.

There won't be any superchilling, regardless of air speed, unless there is evaporative cooling involved. The tank will stabilize at whatever the ambient temperature is, even when moving. If you expect freezing temps, leave a bleeder valve open and don't completely fill the tank so that it doesn't split from expansion.

 

[98dango]

I currently live in Montana and freeze is always a concern. When I get home to Washington I plan to make a under truck tank.

 

[Miller315]

Thanks all, the discussion is great. Just to clarify, I am looking for a small/ inconspicuous water system. I still want/ need to keep the bed open for "stuff". For the most part, it would be used for quick cleaning, washing dirt and sand off kinda thing. My thought was under the truck would keep my bed open, hopefully keep people from messing with it, and give me enough to wash.
When I hunt we use tents and are usually out in the middle of no where. There never seems to be a shortage of water, so I could use a bucket or jug and refill system if needed.
As for freezing, it would be a concern during the late hunt. Usually hit up eastern wa. where it gets a little cold sometimes. I would need to keep aware if it's gonna be cold enough to freeze. Probably drain the tank(s) overnight.

 

[98dango]

I think your under tank is cool and I agree with not needing to mount them angled and what not. The truck is almost not level.

 

[Ducky's Dad]

I have had my roof-mounted tanks out in mid-20s temps overnight without a problem, but days were around 50. I just make sure there is expansion room inside the tank in case it freezes. The larger the diameter of your pipe, the less susceptible to freezing you will be.

 

[Miller315]

Ok, so is it a feasible idea to run a hose from one pipe/ tank under the drivers door to another pipe/ tank under the passenger door? I would need to get around the transfer case and / or driveline, depending on where exactly the tanks go and where the hose runs. Also the exhaust. What would be the best way to protect it from the heat?