At Royal Caribbean Cruises, Michael Bayley, executive vice president international, said he sees growth opportunities everywhere. At the same time, he cautioned that numbers can be a bit misleading, when Europe claims a growth rate of 10 percent on 5 million passengers, and North America 5 percent on 11 million passengers.

All commercial ships face the same risks, but to varying degrees, according to Commander Wilford R. Reams at the U.S. Coast Guard Cruise Ship National Center of Expertise in Fort Lauderdale. These include fire, flooding, piracy, security and the environment.

In addition, cruise ships are subject to some unique risks, such as crowd control and crisis management issues, based on the large number of people onboard, Reams said. However, STCW (standards for training certification and watch-keeping) provides a basis for safety and people management, he added, noting that cruise ships have staff dedicated to crisis management, including a safety officer.

While rating ships on an intricate point system, luxury is ultimately in the eye of the beholder, according to Douglas Ward, author of Berlitz Complete Guide to Cruises and Cruise Ships 2011.

Not so fast, according to Ron Kurtz, president of the American Affluence Research Center, who defines true luxury products by per diems, which should be $500 and higher.

Newbuildings continue to evolve, even after they are contracted, as evidenced by the fifth Solstice-class ship, the Celebrity Reflection, which is switching to the latest generation of ABB pods and a different manufacturer for its main engines.

“The pods are next evolution and more robust,” said Greg Purdy, vice president of marine operations at Celebrity Cruises. He added that the pods on the other Solstice-class ships “are fine, but the new version allows some components, including roller bearings, to be changed with the ship in the water.”

That charge, however, is vehemently denied by cruise lines. “Our main dining rooms are the heart of our dining operation, and we would never do anything to undermine that,” said Scott Steenrod, associate vice president of food and beverage operations for Celebrity Cruises.