Persistent world, yes please,
I'm flying through these DOS submarine sims and will eventually find my way back to Dangerous Waters. Then I'll seek DW mods to see if I can get that illusive old-school single-player immersion I'm looking for.
BTW, kudos to Cold Waters with the 1984 campaign (including President Reagan's resolve). 1984+ is the time-frame I do all of my simming and I will look into this sim one day with a newer PC.