No injuries were reported among the 2,543 passengers or 1,269 crew aboard, said Cunard Line President Carol Marlow. She said she hopes the ship can return to sea by Wednesday.

The ship will undergo further inspection to find out the cause of the problem in one of the ship's four motors. Marlow said it is possible the ship "hit a submerged object," but that is something the inspection in port will have to determine.

Cause investigated
The ship returned to port Tuesday night with the aid of a tug. Marlow said she the ship will undergo an underwater inspection in port and be repaired.

"We will carry out that investigation and see what needs to be done with that motor," she said Tuesday. "We fully hope that we will be leaving port again sometime tomorrow."

The cruise was on its first few days of a 38-day cruise that began in New York on Sunday and is to eventually go around the southern tip of South America, moving into the Pacific Ocean and up to Long Beach, California, where the original Queen Mary is docked.

The cheapest room for the 38 days is $8,399; the top suite runs $80,000.

The motor problem was reported shortly after the ship left Port Everglades at 1 p.m., when the ship was about four miles out to sea, Marlow said.

Coast Guard spokesman Mike Judge said Queen Mary 2's crew called the Coast Guard to report unusual noises and vibrations from the engine room, and said the ship may have struck a submerged object.

Marlow said crews determined the ship should return to port. One of four propulsion motors experienced some kind of problem.

"That can potentially affect the speed of the vessel," she said.

The ship can still travel with three motors if necessary, she said, but that could slow its long voyage and affect its itinerary. With four motors, the ship can travel up to 30 knots, or roughly 34 mph.

The Queen Mary 2 -- dubbed the QM2 for short -- is the biggest passenger vessel in the world, stretching 1,132 feet in length and weighing more than 150,000 tons.

The ship features a planetarium, 22 elevators and the world's largest floating library. Its whistle can be heard up to 10 miles away, and its power plant produces enough electricity to light a city of 200,000 people. It can hold up to 2,620 passengers.

At 1,132 feet in length, it is 148 feet longer than the Eiffel Tower is tall (984 feet) and 113 feet longer than the original Queen Mary, which remains a huge tourist attraction in Long Beach.