Originally Posted by green_rd
Both the Splendor and Liberty engine room fires left the ships nearly powerless. I know next to nothing about ship engine rooms or power systems so my comments/questions are purely out of ignorance.
I have always assumed that modern cruise ships would have port and starboard engine rooms separated by a firewall each with separate fire suppression systems. I know with even the most redundant systems there must be a cross over point that can be a single point of failure. Nevertheless, you would think the remaining engine would be sufficient to provide basic hotel services.
I can answer some of your questions.
Most of the ships built by Fincantieri do not have port and starboard engine rooms - but they do have forward and aft engine rooms. That is, one is just forward of the other. There is a watertight and fireproof steel bulkhead between the two engine rooms.
Since the ships are diesel-electric, each engine room has it's own electrical switchboard.
These two switchboards feed into a main electrical station that powers the ship. In theory, if one engine room is rendered inoperable, the other one can still provide power and propulsion.
But in the past few years, when engine room fires have taken one engine room out of service, collateral damage has been done to the main electrical station. Even though one engine room is still operable, the electric power it creates cannot be sent through the damaged system to the rest of the ship.