Docking a behemoth: Triumph on final leg to port

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In this aerial photo, the cruise ship Carnival Triumph is towed into Mobile Bay, Ala. Thursday, Feb. 14, 2013. The ship with more than 4,200 passengers and crew members has been idled for nearly a week in the Gulf of Mexico following an engine room fire. (AP Photo/Gerald Herbert)

MOBILE, Ala. (AP) — At nearly 900 feet long, the 14-story Carnival Triumph is the largest cruise ship ever to attempt to dock at Alabama's port of Mobile. Authorities caution that the Triumph's final leg requires hours of careful nighttime maneuvering as tugboats ease it up a 30-mile ship channel dredged across a shallow bay.

The Alabama Cruise Terminal — Triumph's destination — hasn't seen a regular cruise ship call on it since 2011. Now a small group of veteran tug operators was entrusted Thursday with bringing the disabled ship up the channel, the last jaunt of a nightmarish tow across the Gulf after an engine-room fire left the ship powerless off Mexico days ago.

Carnival spokesman Terry Thornton said Thursday afternoon that he didn't expect any problems in the final phase of the tow.

"Our tug operators are experienced; our ship team is experienced. We don't expect any difficulties with docking the ship at night," he said.

After the hulking ship pulled within view Thursday of Alabama's Gulf Coast, however, there were difficulties with the tow.

As the Triumph neared the shipping channel in the wide bay, Thornton said, tow gear broke on one of the boats. Then a tow rope snapped on another tow vessel, forcing a delay before the slow crawl resumed.

By Thursday afternoon, the ship was entering Mobile Bay — a broad expanse of tepid, shallow water only 10 feet deep in many spots. Alabama's only 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 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 500 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 guide 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 came Thursday afternoon as the ship entered the lower, southernmost part of the bay. He said the ship and guide boats must negotiate several turns and crosscurrents swirling from a nearby barrier island.

The terminal where the Triumph was 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 several years.

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