New MythBusters, Episode 3

Dutch Oven, never heard flatulence called that before.
Anyone care to venture the origin of that phrase, other than "I heard it down the pub one time"?.
Is this an American thing?. is it regional?.
However, busted, busted well, and thank gawd it is, because you just know some plonka will try that at home in the garden.

Water heater.
Who da heck puts a water heater that low anyway.....
Surely you have to think that many homes with water heaters have foundations, and indeed, a water heater on the ground level may be higher than the chassis of a vehicle, so good call for re-visit.

But in choice of RV's....
Here we have the Caravan, the towed-behind-a-car mobile road block, and for much of what I can remember, most of them these days are mostly Plastic, reinforced fibreglass, chipboard MDF and plastic insides, and I would guess that you could stack three or four side by side in a row and the heater is going to clear most of them.

I therefore have questions.

How MUCH power in a water-heater?.

On remembering the one with the Gas cylinder that set off like a rocket when the head was detached, and what damage that did, and on reviewing the highspeed frame by frame on my own TV of the smaller heater, I am guessing maybe a house wall, not just a shed.
So will it breeze through a breeze-block and brick double skin house wall?.

And then how many caravans/RV's as well?.

We can kind of see already that its going through the RV's. so, ramp it up, what damage will it do to any other kind of vehicle?.

The re-do on this kind of looks like it could be a lot of fun.

However, I have a suggestion.....
You already know what kind of temps and pressure your getting from steam.
Would there be a way of supercharging the system in that a high pressure "shot" of pressurised steam from another device could be used to trigger the water cannon, thus making the exact time of departure a known, instead of having to wait around for hours?.

Here's the suggestion, build a steam engine, and instead of the usual cylinders to power other things, send the shot of steam straight down the pipe to the water heater cylinder that has been filled and pre-warmed to close to the desired temp, to instantly flash over the cylinder to departure levels.

Of course a instant release system would be needed...

Or... steam cannon idea, the system used to launch cars in special effects, just attach a water heater filled with hot water to the front of one of them, "bottle rocket" style...
We already know what kind of pressure your going to get with a water heater, you can easily replicate that without having to wait for another one to fail?.

But this method could be used to fire off a series of heaters in quick succession for repeat testing of what other ideas needed testing?.

Your sort of creating a water-heater machine gun?.

And who wouldnt wanna see that go boom?.


Super-super size, have the navy got any spare cannon barrels lying about that could be used to aim a few water heaters with pin point precision and a shot of steam ?.

Now THAT I want to see.

The largest guns ever carried by a warship were the 18 (actually 18.1) inch guns on the Japanese Yamato class battleships. The largest carried on a US Navy warship were the 16 inch guns of the Iowa Class Battleships, with modern (US) ships carrying a 5 inch gun (Which has been more or less a standard fixture on US warships, at least in terms of caliber, for some 100 years)

The diameter of the smallest water tanks I can find are 20 inches.

Leaving out if MB would be interested in trying this, the only concern would be finding a location where they are not going to hit anything. They would be better served just using a water pipe, which would be wide enough to accommodate a tank.

Note; They would need to add about two inches or so to the diameter of the pipe to account for the power and water connections, which tend to be located on the side of the tank.

We have proof of concept, in that a water tank will fly....
On super-sizing, do we need to be all that exact?.
I know a few people who could weld copper into a cylinder shape, minus all the heat jacketing, and leave you a couple of ports on the base, which we know is where they are going to fail, to any size you need?.
And probably a dozen at darn site cheaper than half a dozen full water heaters..?.
This way, the base gets left in the breach, you dont need to think of having them fly off with pipe attached, you get to keep all the sensors as well, and just the top flys out.
Which if you aim "Out to sea", pretty much fire and forget. [check for shipping first?....]
Heck take the full experiment Naval.. pretty much sure if you ask the Navy nicely they will jump at the chance?.

besides which, the internal tank on a water heater is welded steel, not soldered copper.

my end analysis, though: supersizing it to naval gunnery is fun to think about, but highly unlikely to happen.

The largest naval barrel they *might* be able to get hold of would be a 5 inch gun.

The 16 inch guns that are not fitted to the four remaining Iowa Class Battleships were disposed of; And those remaining ships are museum ships they will NOT be allowed to run tests on.

Over the counter water heaters cost around $400 new in the US for a basic tank. Although I suspect MB may have been getting older second hand tanks from companies that removed them from homes when they installed a newer heater or demolished the building.
Although MB would probably be able to make a tank for themselves, the material savings would be offset by the construction time and above all safety concerns - Any tank they make would be of unknown quality. Whereas over the counter tanks, even second hand, will be a known quality in terms of failure pressures. These factors mean that the $400 baseline figure is worth it, and allows for two or three tanks for more than one test. Even if they did make their own tank they would simply not have the time to make two.

So practicality and safety dictates using an existing tank, which gives a minimum bore size of 22 inches. This is far beyond the size of any gun the US armed forces have ever had.

Simple dirt would be the most viable option; Concrete has to be poured within about an hour and a half of being put into a cement truck* and any location they could safely test firing a water-heater cannon is probably going to be outside this distance when roads and location of facilities are taken into account. You also run into problems of clean up, which would be time consuming and expensive.

With dirt they just need a digger, which due to its tracked nature would also be able to get to places no cement truck could.

Yes, the pipe is most likely going to get destroyed during testing, another reason for going with PVC which is cheaper. So embedding the pipe in something else is not about saving the pipe but making sure that when it fails it doesn't scatter sharp chunks of material over the landscape where they could pose a danger either to anyone around during testing or to people and animals afterwards.

(*This is why it is not unusual to find that major construction jobs, especially those in more remote places; or at least not well served by roads, actually have concrete production facilities on site.)