In steam trains it is often injected to the chimney to increase draft, forcing more air through the firebox, improving combustion. This of course uses up a mass

In steam trains it is often injected to the chimney to increase draft, forcing more air through the firebox, improving combustion. This of course uses up a massive amount of water. For this reason most steam engines in ships and elsewhere generally did have condensers & reused the steam as feedwater, as you describe.