It is becoming a familiar tale: When the cruise ship was towed into port, the endless hours for passengers of sleeping on deck and going without electricity or toilets were finally over.
"It was really hell," said Bernice Spreckman, 77, of Yonkers, N.Y. "I used my life jacket, which was flashing with a little light on it, to find a bathroom, it was so dark."
Spreckman was not among the 4,200 people aboard the Carnival Triumph who this month endured five days of sewage-soaked carpets and ketchup sandwiches. Her trial at sea came in 2010, on another ship run by Carnival Cruises, called the Splendor, which carried 4,500 passengers.
On both boats, fires broke out below decks, destroying the electrical systems and leaving them helpless. A preliminary Coast Guard inquiry into the Splendor found glaring deficiencies in its firefighting operations, including manuals that called for crew members to "pull" valves that were designed to turn.
But more than two years after the episode, the final report about what happened on the Splendor has yet to appear, a reflection of what critics say is a pattern of international regulatory roulette that governs cruise ship safety.
While the Splendor was based in the United States, the ship was legally registered in Panama, meaning the Panamanian Maritime Authority had the right to lead the investigation. But after the 2010 fire, Panamanian regulators chose to have the Coast Guard take over the inquiry. Then, officials in both countries apparently spent months trading drafts of their reports.
One official in Panama said the authority had completed its review of the Splendor report in October 2012. But a Coast Guard spokeswoman, Lisa Novak, said it still had not "finalized" the report. In case of the Carnival Triumph, the regulatory scene will shift to the Bahamas, where that ship was registered.
In a recent letter to Coast Guard officials, Sen. Jay Rockefeller, D-W.Va., said that cruise ships seemed to have two separate lives. Only during days near port are they closely monitored.
"Once they are beyond three nautical miles from shore, the world is theirs," said the letter from Rockefeller, who has headed recent inquiries into cruise ship safety.
Cruise industry officials point out that seaborne vacations are extremely safe and that some 20 million people go on cruises annually, with few problems. The most glaring exception to that record occurred last year when a vessel operated by a subsidiary of Carnival, the Costa Concordia, ran aground off the coast of Italy, resulting in 32 deaths.
In case of the Triumph, the Coast Guard has said that the ship's safety equipment failed to contain the blaze. And both the Triumph and the Splendor returned from their aborted voyages without serious injuries to passengers or crew.
But those successes also underscore what most travelers do not realize when they book cruises: Nearly all ships lack backup systems to help them return to port should power fail because it would have cost operators more money to install them.
The results are repeated episodes involving dead ships, with all the discomforts and potential dangers such situations can bring. In another case, in late 2012, the Costa Allegra cruise ship, a sister ship of the Concordia, lost power after a fire in the generator room and it had to be towed under guard from its location in the Indian Ocean.
In many ways, passengers aboard boats like the Triumph and Splendor were lucky because the ships were disabled in calm weather, rather than during storms, far out at sea or in pirate-infested waters, experts said.
"Anything that knocks a ship dead in the water is serious," said Mark Gaouette, a safety expert and former Navy officer.
Meanwhile, overall safety troubles may increase, experts say, as operators introduce a new generation of megaships. Massive new vessels like the Oasis of the Seas, operated by Royal Caribbean, can carry up to 5,400 passengers and 2,160 crew members. That is one-third more than the number of people on vessels like the Splendor.
Experts say that evacuating any vessel is a dangerous, last-ditch procedure. And the prospect of doing so on a ship like the Oasis of the Seas is daunting. It carries enough lifeboats for 6,500 people; or 1,000 seats fewer than its maximum capacity. A spokeswoman for Royal Caribbean, Cynthia Martinez, said that, if necessary, crew members would have to slide down emergency escape chutes into life rafts.
It was more than a decade ago, just as operators were building a generation of ships like the Triumph and Splendor, that maritime experts began calling on them to improve vessel safety.
In 2000, for example, a U.N. agency involved with ship safety, the International Maritime Organization, began developing such recommendations. One required operators to equip cruise ships with backup engines and generators that would take over when a vessel's main engines were knocked out by a fire or another cause.
There are many reasons for having such redundancies, experts said. Along with the loss of electricity and refrigeration, a vessel without power can pitch violently in strong waves. Also, a powerless boat might have to be evacuated if more serious problems develop, a last-ditch solution that experts say should be avoided if at all possible.
"A boat is the best life raft," said Gaouette, the safety expert, citing a well-used adage.
Under a rule from the U.N. agency in 2006, any cruise ship built after July 2010 is required to have such a system. But during the past decade, as ship operators raced to build bigger boats to supply a growing consumer demand, they chose not to voluntarily add backup systems to new vessels.
Larrie D. Ferreiro, a naval architect and historian at Catholic University in Washington, D.C., said that the choice for cruise operators was simple: A boat is just so big and a company can either put more equipment or more people on it.
"The more passenger cabins you can fit into that envelope the more revenue you can get," Ferreiro said.
Today, only about 10 cruise ships have such equipment, said John Hicks, the vice president for passenger ships for the North American division of Lloyd's Register, a consulting firm. The Royal Caribbean spokeswoman, Martinez, said that the Oasis of the Seas and a companion vessel, the Allure of the Seas, have such backup systems.
For passengers on most other cruise ships, however, the possibility of getting stuck on the water perhaps for days may be an inevitable part of buying a ticket.
Spreckman, the passenger on the Splendor, said she and her friends who were also on that boat were stunned when they heard about the Triumph. It was as if Carnival had not learned anything, she said.
"All my friends called me, 'Did you see that?'" said Spreckman, who is a Weschester Country legislator. "I cannot believe they did not learn the lesson. It happened before and it happened again."
By BARRY MEIER and JOHN SCHWARTZ
The New York Times