Steam jet boats

The power is in the steam that comes out of the boiler. Running it through cylinders and gearing and shafts and a propeller does not make it into any more power :: efficiency cannot be more then 100%. with a steam jet, the pipe from the boiler to the blast nozzle would have to be kept as short as practicable to avoid friction losses.

If the steam blast is turned into an air blast by a PDX-type device, what would be the % efficiency of that power conversion?

Then if the resulting air blast came out of an underwater stern vent, the blast it would push against the water as well as having a jetplane-type effect.

 

Normaly, EACH time you change the original energy amount of BTU's in and out of states of energy, or use gears or whatever, you have to lose a % of the original amount. -----------------------That is why solid fuel missile motors are so eff. One match and it is moving.