Updated

At nearly 900 feet long, the 14-story Carnival Triumph is the largest cruise ship that has ever sought to dock at Alabama's only seaport of Mobile. Authorities said the Triumph's final leg required hours of cautious nighttime maneuvering as tugboats eased it up a 30-mile ship channel from a shallow bay.

The Alabama Cruise Terminal hadn't seen a regular cruise ship call there since 2011. The Triumph arrived late Thursday night, its relieved passengers joyously shouting "Hello, Mobile!" as many cheered and some danced aboard the decks as the ship got into position for final docking — a process unfolding with slow, careful steps late at night.

A small group of tug operators was entrusted Thursday with guiding the disabled ship to safe harbor, the final phase of a nightmarish tow across the Gulf after an engine-room fire left the ship powerless off Mexico last weekend.

Carnival spokesman and executive Terry Thornton said an experienced crew was called on to bring the hulking vessel safely the last miles into the U.S. port.

"Our tug operators are experienced; our ship team is experienced,"he said as the ship began its final trek into port.

The ship on Thursday initially had entered Mobile Bay — a broad expanse of tepid, shallow water only 10 feet deep in many spots. The seaport is at the mouth of the Mobile River and the head of Mobile Bay — an industrial complex of shipyards, paper mills, plants and refineries.

The ship channel is a safe entry point across the bay for big vessels, tankers and cargo ships. That navigation channel is about 40 to 47 feet deep and about 29 miles long, transiting part of Mobile Bay to the mouth of the Mobile River. Its width varies from 400 to 775 feet at points and there are various turning basins and feeder channels.

At its entry point, the ship channel is about 400 feet wide. The Triumph at its widest is 116 feet, leaving only so much room on either side as four tugs guided the ship — one at the front, one on each side and one at the rear.

State Port Authority Director Jimmy Lyons said the most difficult part of the last leg home came Thursday afternoon when the ship entered the lower, southernmost part of the bay. There the ship and guide boats had to negotiate several channel turns while dealing with the water's tricky crosscurrents swirling from a nearby barrier island.

The terminal where the Triumph headed was built for Carnival. But it hasn't had regular traffic since 2011, when Carnival stopped running cruises out of Mobile after using the complex for several years.

The city is trying to get cruise ships to return full-time to the Mobile terminal.

Authorities said getting passengers safely off the ship and on their way home was the priority Thursday night. They said the vessel would then be taken later to a nearby facility in the port for damage assessments.