The "generator" everyone talks about also probably powers ship's service hydraulics, which should run the bow thruster and the "power steering" for the rudder. It would make sense to have a midsize diesel engine run all this stuff at a constant RPM while the big engine turns the prop.
I bet UPS/ battery only powers the most spartan stuff-- radio, navigation lights, radar. It's not turning the ship.
I'm disappointed the little engine was run on junk fuel while still in US waters but hey, profits, right?
I was just thinking what happens if the generator fails and then the backup fails. It sounds like it lost propulsion in addition to steering and just drifted. I was under the impression that it needed electricity to operate the engine. I get that older diesels operated differently, but not modern, computer controlled diesels.
If the APU fails in modern airliners, they still have batteries to power the control systems until that can come back online.