Ok so you get another container with a dummy load to enable a simple connect disconnect at the loading dock, fine that would work, apart from what you would do when the next load arrives, do you just manufacture dummy loads and take them back to the start, how do these get back to the other side where they are needed, and why don’t we use the same method to move the initial cargo?

If you just have a tank for the water, you could just fill it before unloading.