Passenger Ferguson said crew members tried to make the situation bearable.
"They did their best to keep our spirits up," she said.
Joseph and Cecilia Alvarez of San Antonio said they were on the lowest deck near the back of the ship when the fire broke out and they smelled smoke coming from the vents. She said there was confusion that night about whether to evacuate cabins, with firefighters running through the halls.
He said some passengers passed the time by forming a Bible study group that drew about 45 people.
"It was awesome," he said. "It lifted up our souls and gave us hope that we would get back."
While the passengers are headed home, Triumph will head to a Mobile shipyard for assessment, Thornton said.
Earlier Thursday — four days after the 893-foot ship was crippled in the middle of the Gulf— the passengers and crew suffered another setback with towline issues that brought the vessel to a dead stop for about an hour just as it was getting close to port.
As the vessel drew within cellphone range Thursday, passengers vented their anger.
Renee Shanar of Houston was on board with her husband, whom she said has heart trouble. They were told they would be among the first to disembark, she said.
"I don't believe them; they've been lying to us from the beginning," Shanar said.
Disgusted by the foul air and heat on the lower decks, many passengers hauled mattresses and bed sheets onto the top deck and slept there, even staying put in a soaking rain. As the ship approached the coast, a slew of Carnival workers removed the bedding and took it downstairs.
In a text message, Kalin Hill, of Houston, described deplorable conditions over the past few days.
"The lower floors had it the worst, the floors 'squish' when you walk and lots of the lower rooms have flooding from above floors," Hill wrote. "Half the bachelorette party was on two; the smell down there literally chokes you and hurts your eyes."
She said "there's poop and urine all along the floor. The floor is flooded with sewer water ... and we had to poop in bags."
The company disputed the accounts of passengers who described the ship as filthy, saying employees were doing everything to ensure people were comfortable.
Some travel agents said cruise prices and bookings have not been affected by the disabled Carnival ship, but others in the industry say it's too early to tell.
Thelbert Lanier was waiting at the Mobile port for his wife, who texted him early Thursday.
"Room smells like an outhouse. Cold water only, toilets haven't work in 3 1/2 days. Happy Valentines Day!!! I love u & wish I was there," she said in the text message, which was viewed by The Associated Press. "It's 4:00 am. Can't sleep ... it's cold & I'm starting to get sick."
Carnival has canceled a dozen more planned voyages aboard the Triumph and acknowledged the crippled ship had been plagued by other mechanical problems in the weeks before the engine-room blaze. The National Transportation Safety Board has opened an investigation.
Passengers were supposed to get a full refund and discounts on future cruises, and Carnival announced Wednesday they would each get an additional $500 in compensation.
Plushnick-Masti reported from Houston. Associated Press writers Bob Johnson in Montgomery, Ala., and Melissa Nelson-Gabriel and Brendan Farrington in Mobile, Ala., contributed to this report.