There are no direct trains between Hamburg and Copenhagen and vice versa from 23 March to 04 June 2018 – so unfortunately the eccentric train on a ship won’t happen!
Recap of my trip on the 09.25 Hanoi to Hai Phong Train LP3, a 2 hours 35 mins ride - costing £4. It was raining cats and dogs in Hai Phong, as you can see!