LOS ANGELES - A luxury cruise liner that limped into San Diego after a fire knocked out its power was lucky in many ways - no one was killed or even seriously hurt, a nearby Navy vessel came quickly with supplies and the mishap occurred in tranquil waters.

Yet the drawn-out tale of the stricken ship shows just how quickly things can go wrong on a giant floating city carrying thousands of people, and it's prompting a closer look at whether ocean liners are properly equipped to deal with the litany of problems that could strike: rogue waves, norovirus outbreaks and mechanical problems that disable ships in treacherous weather.

"If you want a completely predictable vacation don't go on the sea," said Carolyn Spencer Brown, editor of the industry trade publication Cruisecritic.com and a veteran of more than 200 cruises. "Ships are bigger and have better stabilizers than ever before, but they are still on the sea and the sea is nature and nature is unpredictable.'"

If the Splendor had been crossing the North Atlantic in the winter - instead of about 40 miles off the coast of Mexico in calm waters - things could have been far worse, said veteran maritime attorney Charles Lipcon of Miami.

"The weather in the North Atlantic, and off the coast of South Africa, can be awful," he said. "They usually try to stay close to port, so if something does go wrong they can avoid that. But sometimes they have no choice."

Another stroke of luck for the Carnival cruise: Navy aircraft carrier USS Ronald Reagan happened to be in the area conducting training exercises, and its 6,000 sailors quickly came to the rescue with deliveries of food and other supplies.

Tugboats weren't far off, and they hauled the 952-foot cruise liner about 200 miles into a San Diego dock on Thursday, bringing weary passengers to shore and ending the three-day ordeal.

Passengers disparaged the food and complained about backed-up toilets, yet praised crew members for calmly getting everyone to life boats that turned out not to be necessary. The blaze was extinguished quickly, and no one was hurt.

But onboard fires have long been a significant concern of investigators, said former National Transportation Safety Board member Kitty Higgins, and it's unusual for a fire to shut down an entire engine room and take out every backup electrical system on board.

"A fire can be quickly contained so that it won't require a ship to return to port," she said. "That raises a lot of concerns."

Four years ago, the Star Princess oceanliner caught fire on a windy night in the Atlantic Ocean as it headed toward Jamaica. One person was killed, 11 injured and 150 cabins damaged before the crew could douse the flames, which were believed to be caused by a cigarette.

As investigators try to determine what happened aboard the Splendor, Higgins said they likely will look at the ship's equipment and also the crew's response. Cruise ships have extensive contingency plans and drills that must pass muster with the Coast Guard, said Eric Ruff, executive vice president of the Cruise Lines International Association. The Splendor had conducted a fire drill - overseen by the Coast Guard - just a day before the engine blew, ship officials said.

The National Transportation Safety Board said the probe into the fire's cause would be conducted by Panama, where the ship is registered. Panama agreed to let the U.S. Coast Guard join the investigation because most of the passengers were U.S. citizens, and two NTSB experts will assist, the NTSB said.

Ships like ocean liners are governed by the laws of the country where they are registered in and under whose flag they sail.

In order to raise revenue, Lipcon said, some small countries such as Panama and Liberia are known to exempt ship employees from labor regulations governing the number of consecutive days they are required to work and the number of hours they are given off between shifts. Lipcon said this has sometimes resulted in crew members so tired they pose a serious threat to the safety of passengers.

"We found a study in Australia that indicated a tired worker, someone who worked shifts of more than 10 hours, reacted the same as a person does when driving while intoxicated," he said. "That means you could have a ship run by a bunch of people who are the equivalent of people who drive when intoxicated."

He also said such countries are reluctant to conduct strenuous investigations when something does go wrong on a ship because that could result in the operator being required to make costly improvements.

"I think you'll find that Panama will just overlook the whole thing," he said of the Splendor mishap. "Otherwise they might have to spend money, and that would hurt Panama's flag of convenience business."