Carnival said the ship's emergency diesel generator failed, but the cruise line disputed notions of a widespread system failure.

"The ship's power plant, propulsion and hotel systems are fully operational. Aside from some periodic interruptions to restroom and elevator service for a few hours Tuesday night, at no time have any of the ship's systems and services not been functional," Carnival said in its statement.

The company said it was flying the more than 4,000 passengers and will give them discounts. By late Saturday, most of the passengers had left St. Maarten by air.

Once all passengers leave the ship, the Dream's crew will sail back to Port Canaveral on Sunday, the company said. The ship's next voyage has been canceled.

Passenger David Howard said he thought conditions were fine aboard the Dream, but said he was frustrated with how his family and other passengers were treated and by the "lack of communication."

Howard said he and his family weren't told until 1:45 a.m. Friday they had to get off the ship by 7:30 a.m., so they had to rush to pack in the middle of the night.

A message from the captain

Dream passengers received a letter from the captain, according to a passenger who e-mailed a photo of the correspondence to CNN.

Capt. Massimo Marino told passengers they would be booked on flights to Orlando or another destination. Passengers with cars at Port Canaveral would be bused from Orlando to the facility about an hour away.

"We sincerely apologize for the disappointment this unexpected change has caused and regret we were unable to provide you with the fun and memorable cruise vacation we had in store for you," he wrote.

The letter also offers passengers a three-day refund and a half-price cruise in the future.

Crisis communication expert Tom Donahue said Carnival may be making the right operational decisions. But the frequency and effectiveness of communications to passengers -- who have no other information source -- are what influences the passengers' perspective.

Carnival Elation

Like the Carnival Legend, the Carnival Elation suffered problems with its Azipod, a crucial part for steering and propelling a vessel.

A tug boat trailing the ship as it travels on the Mississippi River is "purely a precautionary measure," the company said.

Memories of the defeated Triumph

In the most publicized case, an engine room fire last month left the Carnival Triumph crippled and adrift in the Gulf of Mexico with more than 4,200 people aboard.

That scheduled four-day cruise stretched into eight days as tugs pulled the vessel into port in Alabama. Food was scarce, passengers sweltered in the heat with no air conditioning, toilets overflowed, and human waste ran down the walls in some parts of the ship, passengers reported.

A class-action lawsuit against Carnival Corp. followed.

The Triumph is still being repaired at a shipyard in Mobile, Alabama, Carnival spokeswoman Joyce Oliva said.