a) what idea is this? you cant give out an idea in 7 words. no picture? no nothing. giving us some insight of how/what it is would help people *maybe* respond here. saying an idea without pics or a definition wont get you anywhere.
Since water can be evaporated and then then condensed it is possible and considering science is evolving, its possible, but might be very expensive and inconsistant, it also may be time consuming and unpredictable. Pretty Origional idea none the less.... I pick A (1st one)
my dad told me once about a ride he rode that involved a log ride type boat and a hi pressure water thing , it was a loop, but the pressure would buid up a little more each time untill it went upside down. sounds dangerous,
Ahhh^. Cannot beat a bit of sheer sense can you[lol].
Back on topic : Your original idea was too small that nobody could see the scientific part of it. You only stated it was a 'water launch', and nothing else. Maybe we should stick to Hydraulics, LSM's, LIM's, Flyweels, Weight Drops and everything else, as unfortunately your idea doesnt seem concept and simple enough, could you link us too it or update this topic with 'large' pictures. Would be very helpfull.
um.. water launch = hydraulic. i'd like to see it.. as far as water vs steel.. the plunger shaft can be stainless, and the actual pump body can be anything you like with a stainless sleeve.. some sort of nylon rubber plastic stuff for the actual seals, and i think you could do it. yeah.. go for it..
the idea wouldn't serve much purpose in terms of finding a new, more efficient way to launch a coaster. the only way you'd make it work is to take the idea of a compressed air launch and replace it with liquid, which Intamin has already done with their hydraulic launch system. If you thought of a design from the view of an engineer, there might be a possibility plain old water could be used. However, you'd also have to think about the problem that steel and water don't get along very well. the thing would rust unless you had some kinda sealent to apply to the track to keep it from rusting which wouldn't wear off.
Why not just stick with Intamin's idea? Obviously it's working. And basically anything oxide based will not work with a metal ... redox reactions and rusting anyone? (btw water is the oxide of hydrogen, hint, hint). You could infact place a layer in between the water and metal, but this would eventually wear off and need to be replaced.