@Sherri_Ingrey @djsumdog @AlphaKiloPapa @LCCMV @softbear @polarisera depending on how much true redundancy there is in the ship's electrical, the same fault that took out primary power could just do the same thing to backup power. there's always going to be some place where primary and backup power meet, and if it's some switchgear right next to the two generators, that leaves a whole ship worth of single points of failure.
in port or out at sea where the ship spends most of its time, not a big deal, send maintenance go to find and repair the fault, reset some breakers or change some fuses, and carry on. i'm gonna guess that they didn't spend a lot of extra money on making electrical systems perfectly redundant all the way to the rudder hydraulics or the bow thruster or whatever the hell else a giant ship needs to not boop a bridge.