Help me stat a steam thrower weapon

[Green-Neck]

Hello fine folks,

My GM is going to run a post apocolyptic game and I'm trying to give my character an intersting weapon. The campaign is semi cinematic and set in nearish future australia.

I'm imagining a weapon that looks much like a ww2 flame thower, except it uses solid fuels like wood and coal to heat water to superheat steam.

I'm thinking of a 30 pound backpack with wand
A brazier that preheats a water tank, then fills a one quart steel tank that heats to about 250 C/480 f, thats about 40bar/600 psi.

The tank would have a temperature solinoid and thermo-electric-generator powered fan to moderate the fire.

My attempt at stating it so far:

Steam Projector,
0-1 yards, 4d cutting pi-
2-5 yards, 4d burn 1x1 cone.
6-8 yards, 2d burn 2x2 cone.

30 lbs, 10 shots, fire 1 per 3 rounds.
Reload 10 litres/quarts water, 2lbs/1kg coal or wood.
Bayonet, for inevitable complications between steam charges.
skill: liquid projector (steam), spear.


I'd welcome any thaughts on semi-realism and more refined stats.

Thanks.

[whswhs]

You're going to need a lot of insulation to carry around a tank whose contents are that hot. With a flamethrower that doesn't arise, because the heat isn't there until you use the weapon and the fuel starts burning.

[Green-Neck]

Thanks Bill.

Hopefully this post apocalyse senario has large ruined building with firedoors.
Such doors can contain high temp (1000 deg c) glass wool insulation, or some other source.

[Green-Neck]

The main reason for the steam weapon, I should point out, is a lack of high quality liquid fuels in the scenario.

[Anthony]

I am going to assume this is intended to be a cinematic weapon, because it's realistically nonsense -- any steam tank that isn't going to simply blow up and kill the operator won't produce a jet strong enough to be useful as a weapon at all. In which case, just invent numbers that sound cool.

[Green-Neck]

Well yes it probably does require some hand wavium, but pressure tanks to the specification above are common in our society, and pressure release valves should prevent an explosion.

I'll leave you with this quote:

In 1988, there was a steam line failure at the Mohave station in Nevada, USA. The hot reheater P11 pipe failed , at 31 bar,g and 593 C temp ( design temp was only 540 C, and it was overheated for 1 yr prior to failure). It failed outside of the plant cafeteria, and killed 11 operators who were eating lunch in the cafeteria.

[Anaraxes]

I notice that your quote is for a source about two and a half times as hot as your proposed weapon.

[Green-Neck]

Originally Posted by Anaraxes

I notice that your quote is for a source about two and a half times as hot as your proposed weapon.

Well, yes, but it gives a the general idea about how dangerous steam can be.

I suspect the most unrealistic part is heating the steam up enough to create the effect described, certainly not in a 2 second recharge.

Using the nozzle of a water jet cutter would help keep the high pressure steam in a very fine cone.

[Anthony]

Originally Posted by Green-Neck

Well yes it probably does require some hand wavium, but pressure tanks to the specification above are common in our society.

Oh, I missed that you gave a pressure and temperature. Figure damage of 1 point burning with a range of a couple inches (a bit more if you don't mind it blowing you backwards like a rocket).

[Rolando]

i think the idea seems cool for a steampunk setting, post-apocalyptic or otherwise, but for a post-apocalyptic setting after the modern world I think it looks too out of place.

The big issue I have is heating water to such dangerous levels in a backpack only with coal or other simple fuels (no petrol or high power batteries).

If you, on the other hand use fire and powdered combustibles (powdered coal, flour, sawdust, any of those mixed with powdered magnesium, or similar) you can do some impressive fireballs and still be somewhat plausible, but most importantly (for me at least) it looks more "right" for a modern post-apocalyptic setting.

As for the damage, call it a 2d burn within 3 yards and 1d burn at up to 7 yards, also add some area of effect and you are done.

the contraption will consist of backpack with the dust and an air compressor blowing air into a tube and the flammable dust gets poured by pressure difference through a hose, as the dust is blown it is ignited by a spark at the end of the tube/wand.

If you still want something similar to a steam weapon it is may be better as a high pressure hot water weapon. A water pump like those to clean pavement with very hot water and with a lot more pressure, it can cut and burn, maybe 1d burn but hot water stay hot for a while over the target making it very dangerous for exposed skin, and very distracting.