Here, I have a video of it in action. The pumps just won't work. I save a save file at that starting position where they'll show the little animation, but for whatever reason as soon as the ship moves it'll never work again.

https://www.youtube.com/watch?v=G14cpK-j6F0&feature=youtu.be

hey, i am sorry for the frustration this caused you.
i just checked, and could reproduce the issue, but it went away as soon as i set up an automated route from the oil platform to the unloading station.
i think its possible to "park" at the right spot manually and get it to work, (the behaviour with normal fluid trains is very similar) but due to the bad maneuverability of the ship its incredibly difficult to hit this "spot".