This is a boat that moves by functioning as a train. It is connected via framed glass panes that are nearly invisible. You could extend the number of glass panes to hide the bogey even further under the river or ocean floor.
This was a collaboration with Stam1o: https://www.youtube.com/@Stam1o
World download available on my Patreon: https://www.patreon.com/posts/day-11-world-30-130915581