Technically it's in beta, however, it's been playable for several years. It's a tiny dev team, who produce a patch or two a year, to add new features (and the occasional bug!). The most recent patch added the engine and e-motor which are both operable.
I've written a post with some suggestions for getting started:
https://www.subsim.com/radioroom/sho...d.php?t=256619
Start with helm, as this can be learned quickly, and being in the control room means that over time you'll pick up a lot of the ins and outs of other positions.
It is a great deal of fun, but, it's essentially at it's best when the boat is multi-crewed, perhaps with another boat or three, and everyone's teamwork results in high tonnages for all. It takes a while to get to develop all the necessary skills! Expect games to last 2-3 hours. Don't judge the game by playing solo or with "bots". Above all, this is a team-game, and many of us play so many times a week with a group of friends.