I love ferry boats! I like the really big ones. When we went to Nova Scotia, we took a ferry from New Brunswick across the Bay of Fundy (Gulf of Maine). It was so big there were semi trucks on it in the parking area, along with a slew of cars and passenger trucks. I think it took us almost 2 hours to go across the bay? We saw pilot whales from up top. Oh that was such a great trip!
Edited to add that I like trains, too. Love them. I want to take a train trip across Canada someday, one of my sisters and I were looking into it before the pandemic struck.
Ferries are heavily used in Japan. I sometimes watch a YouTube channel that some guy does about travelling on them (and trains). He often does overnight ferries, in everything from pod rooms to first class suites.
They make most of their money from truck trailers.
Here is an episode...
CD