Carnival Splendor, left drifting without power off Mexico in 2010, was built to a modification of the Concordia design.
A CARNIVAL cruise ship built to a modification of the Costa Concordia design suffered major power failure off Mexico in 2010, leaving experts asking whether that earlier incident might have parallels to Friday's casualty off the coast of Italy.
At this stage, with little hard information on the technical side of the Costa Concordia casualty in the public domain, any comparisons are by nature tentative.
However, it is known that passengers reported a power blackout and what sounded like an explosion on board. Others said that they were initially told over the public address system that an electrical fault had developed.
The Costa Concordia is powered by six diesel-electric engines and some marine engineers believe that the idea of a power surge interfering with the generators, prompting the back-up to fail as well, deserves to be considered. Loss of power would entail loss of navigational control, which might explain why the vessel went on to hit a rock.
Attention has thus turned to events on board Carnival Splendor in November of the year before last, when that ship was left drifting without power following a fire in an aft engine room.
Air conditioning, hot water and mobile phone and internet connections were all down. Food supplies were maintained by having US Navy helicopters airdrop spam, croissants and pop tarts.
None of the 3,299 passengers and 1,167 crew members were particularly the worse for wear after Carnival Splendor was towed back to California by tugs.
The 114,147 gt Costa Concordia and the slightly smaller Carnival Splendor, at 112,000 gt, are not technically speaking sister ships. However, both were built at Fincantieri's Sestri yard, in 2006 and 2008 respectively, with Carnival Splendor constructed as a one-off modification of the Concordia class.
One source who acts as an expert witness in marine engineering, but who asked not to be named, said that based on his knowledge of cruiseship engine room configurations, the possibility of a common design fault could form one line of investigation.
Specifically, there is the matter of whether propulsion power and accommodation power should be entirely separate, as they are on older cruise ships.
Cruiseships are equipped with sizeable power plant, he said. Both Costa Concordia and Carnival Splendor have diesel-electric propulsion with four generators, with two larger ones on the outboard and two slightly smaller on the inboard. These engines drive alternators that are linked up to two synchronous motors that in turn drive two propeller shafts.
"There is a very considerable electrical load there. They have transformer systems and they have systems that smooth out the peaks and troughs of the currents. And of course, any of that equipment could go wrong at any time," the expert witness pointed out.
"There are back-up systems. But how quickly do they act, and what are the consequences? Without knowing more about Costa Concordia, it is difficult to speculate."