Ports of Call on the Commodore 64. One of the first video games I ever played. Set up a shipping company, buy a ship, buy low and sell high and get better ships. Occasionally you have to take control of the ship (incredibly rudimentary, but it was 1986, give them a break) to dock or leave port, avoid a collision or avoid reefs, but for whatever reason I keep coming back to it.
https://store.steampowered.com/app/1085260/Ports_of_Call_Classic/