From: Charleston, WV
I am a mercant ship Chief Engineer who has worked on cruise vessels in the past (not Carnival).
The Triumph had two engine rooms, but they are not completely segregated as far as systems are concerned. Most cruise ships are this way, each engine room has 2-3 diesel generators, and nearly all ancillary systems required for the operation of the engines (water, air). The usual crossover is the fuel system, which is segregated between the two engine rooms, but all of the fuel handling equipment (centrifuges, heaters, pumps) are usually in one compartment (different from the engine rooms). A cruise ship "engine room" or engineering spaces, usually runs the length of the ship, and can be in as many as 12 separate watertight compartments.
The diesel generators generate electricity for the entire ship: lights, a/c, water, galleys, and propulsion as most cruise ships are diesel-electric propulsion. The Triumph had a leak on a fuel return line from one engine in the aft engine room. This sprayed hot (280*F) and high pressure (225psi) fuel around which must have contacted a hot surface and flashed.
I would have thought that the engineers could have isolated the fuel to the aft engine room, and restarted the forward generators to power the ship. If the propulsion motors are in the aft engine room, then propulsion was probably not possible, but hotel services could have been restored. It all depends on the design of the electrical system. The Carnival Splendor last year, also had two engine rooms, but the fire in one damaged the wiring from the other, so the redundency was out.
The previous problem the Triumph had was a problem with an alternator (the generator attached to the diesel), so one thing really did not have anything to do with the other.
The emergency generator is designed by international (IMO) regulations to provide power sufficient to safely disembark all passengers and crew. This means primarily: lights, steering, some ventilation, fire pumps, bilge pumps, and the like. The emergency power buss is 480v, while the main buss is 10,000v, so there is usually no way to feed back from the emergency to the main power to get things like toilets working.
On a lighter note, for those intending on cruising, you do not need to stand up when flushing a vacuum toilet, any more than you do on an airline toilet (see Mythbusters). While we have found nearly everything imaginable (and many not imaginable) down at the vacuum pumps (underwear, dinner napkins, towels, clothing, rings, etc), it will not suck you onto the bowl.
Cruise ships are equipped with advanced waste water treatment systems that cost millions. The effluent is tested by independent labs every couple of weeks, and is essentially clean, fresh water (I won't go along with the sales brochures and drink it however!). My ship processed 700-900 metric tons of waste water (black water from toilets, gray water from sinks, showers, galley water and laundry water) every day, in port or at sea. (That's about 200,000 gallons/day)
On the Triumph, guests were asked to do #1 in the showers, as the gray water system from them could be stored in sewage tanks, and this flows by gravity. #2 was done in biohazard waste bags, and deposited in the passageway, where crewmembers were standing by to take it for storage/disposal. Most of the "mess" was caused by guests not following instructions and continuing to fill non-flushing toilets with their deposits.
Some accounts say that there was power for movies in the lounges, running cold water, power to charge cell phones, and cooked meals. I've seen photos of hamburger dinners. Again, some claim that there was cooked food, but that after a long wait in line, there was only onions and buns left. I've heard that this was caused by the first in line piling up several burgers regardless of limits.
I've even heard of a passenger who saw several others sitting in deck chairs, with their cell phones on charge, and talking to the media about how horrible the conditions were. It just reinforces my opinion of the human race, that we are all out for ourselves, and will resort to the worst possible behavior in order to keep from being inconvenienced.
In response to Paladin: The fuel is hot and pressurized. The pipes are insulated and anti-spray tape is applied at every joint to minimize spray onto hot surfaces. Hot surfaces are insulated. These things happen, on cruise ships, merchant ships, and Navy ships (though the Navy no longer uses heavy oil, kerosene sprayed on a gas turbine results in the same problem). Could Carnival's maintenance have been better? Won't know until the investigation is over. Ship design is constantly evolving, and new regulations are constantly being generated to make things better.
Thank you for shining some knowledge on this topic 21pzr, I was really starting to wonder just how close to the truth the media had gotten with this story. I had my suspicions that it was being embellished a bit and it seems that my suspicions were well founded.