Comment by dataviz1000

The YouTube channel SmarterEveryDay was invited to film on an Ohio class nuclear submarine training in the Arctic. [0] You can see how many of the system are mechanical and not electronic in the demonstration especially the ballast controls. Most if not all boats and ships can control the throttle mechanically so if the boat loses its electronics such as a wave smashing the windshield in, it is still possible to control the rudder and throttles. I was very surprised at the lack if mechanical controls on the recreational submarine.

[0] https://www.youtube.com/watch?v=XFJnWp1tAdU