Planning my cargo trailer conversion, black water questions

[rival1]

Hello all I’m in the planning stage of the conversion of a 20x8 cargo trailer. I think I have a floor plan figured out my only hang up at this point is exactly how to plumb it, mostly the best way to do a black water system for the toilet. I want the system to be as close to an rv or boat system in terms of usage which is why I don’t want a ports potty or composting toilet. Anyway just wondering what people on here have done some of the videos on YouTube show cutting the floor and having the tank below the trailer which seems fairly straightforward other ideas are to raise the floor around the tank and mount the toilet up a bit. Anyways just looking for ideas so I can wrap my head around this a bit easier. Thanks in advance Steve

[hankaye]

rival1, Howdy;

Welcome to the forum. There are a bunch of folks that have done several different methods
both raised floor and underneath. There is the enhanced Google search box up top to help
you get started while waiting for others to chime in. Please be sure to take and post pix of
your project. That's how the learning gets shared.

hank

[road-dawg]

Amount of clearance underneath will be a major factor in how you proceed.

[aggie79]

Here are links to a couple of older posts on black tank installation:

The link within this post shows a raised platform toilet installation: http://www.tnttt.com/viewtopic.php?p=1139128#p1139128

This link shows a flush toilet installation: http://www.tnttt.com/viewtopic.php?p=1139144#p1139144

This is another discussion with links: http://www.tnttt.com/viewtopic.php?f=54&t=63238

[travist]

Clearance is definitely a factor.

I did an under mount system, which can be seen here: viewtopic.php?f=42&t=71478

For the toilet you really want you black tank to be as close to right below your toilet as possible unless you want a pump and macerator type thing, which is in my mind just another thing to maintain.

Also don't forget to consider front to back weight balance. you want 60% in front of the axle and 40% behind (which you probably already know), but don't forget to factor full tanks into your thinking, which depending on size can add several hundred pounds.

[Grummy]

In addition to the above,... How Much ? How many gallons of black space do you really need or want ? It's all a bit of a guessing game that depends on how often you can dump, how the continuously changing weights affect tongue weight as well as what your options are to compensate when necessary. And then, yes, how much clearance you have underfloor. Most regular old cargo trailers do not have much compared to modern travel trailers all up there in the wind.

Then your drain has to be located such that it is lower yet, and you do not need to tear that off in a driveway approach at a fast food place, or anywhere for that matter.

I went porta-potti this time because a 5gal unit can last more days than I thought with just two people who have other options during the day, but really only prefer to have it at night for the convenience factor. Easy to deal with over the black tank in my situation.

I've often thought that if I had to do a true black tank again, I would keep it's size on the small to moderate side, then find a way to carry and store a portable tank for dumping without having to move, or just for the emergency additional space. But I would not want to have to SEE that tank either, so It would need it's own storage spot.