You all probably know the typical vehicle simulation game: pay 20 bucks, get three different cars/trains/tracks/airports/planes/…, and for anything more you have to pay another 10 bucks a piece. The games are pure rip offs meant to extract as much money as possible at minimum value provided to the customer.
But then there are games that are sold as one single complete product and are of high quality. Such as Derail Valley or Beamng Drive. Those are products I really value and that manage to impress over and over again. They are continuously in development and feature a detailed simulation, open world, various game modes, detailed difficulty settings and more. This makes them playable forever and ever without getting boring.
I never played a ship simulation before. Does something in the same spirit exist for ships? Doesn’t matter if small boats or big cruise or transport ships.


There’s a few games in development around the edges of this type of thing - though I think nothing as polished currently.
Perhaps worth looking at: Following Seas
Sailwind
Salt
Seafarer The Ship Sim
Sail the Seas
I’ve played Sailwind and Following Seas quite a bit, but not the other three (they’re on my wishlist at the moment) - I can’t guarantee any of these are good, or do what you’re after - but maybe a starting point for looking.
You might find them more like “Euro Truck Simulator on a boat” than “Derail Valley/Beam NG on a boat”.