What is the cheapest way to build an Argus (water) Jet Engine, using river water for a hydraulic medium?

I'm aiming to use no more than $20 building it. I'm aiming for an equivalent force generated to replace a 2 hp motor (the canoe is Ramex plastic and only rated for a 2 hp. motor). I have : old cans including several sizes of olive oil cans for a boiler, a map gas welder, some brass and the means to found this, but not the means to forge anything, some bearing silver, a very small dab of epoxy, several old shoes for leather reed valves, a Coleman stove. Some lengths of copper wire for winding around and soldering up to reinforce any home made low pressure boiler as per a Stanly Steamer.

Presently, I'm thinking the water would go into a series of cans welded or soldered together, past a leather reed valve, and thus have momentum. It would be forced in by a low pressure steam implosion as the steam cools, as in a New-comb (sic) steam engine. There would be another valve on the reverse side to form a barrier for water entering that side.

If someone has plans to a similar engine as I describe, I would appreciate this very much.

I'm considered "mentally ill", after severe brain injury in State service and made fun of nearly constantly and denied needed medical attention. I have medical records in Augusta and I'd like to politely confront the records keepers there and gain as much help in recovering lost funds as I can by proving that I'm not nuts. The engine will be used to power a boat. If I can prove this is a reliable means of transport I'll be less likely to be literally put away for being too audacious.