MIAMI (Reuters) - The Carnival Triumph cruise ship returned to service on Thursday, four months after an engine room left 4,000 passengers and crew adrift in the Gulf of Mexico without electricity and adequate sanitation.
Triumph underwent $115 million in repairs and upgrades, including several new entertainment features, the company said in a statement.
The incident prompted Carnival Cruise Lines to announce a $300 million "enhancement" of its 24-ship fleet, including a major re-wiring of engine rooms, the addition of backup power generators and new fire safety equipment.
The parent company of Carnival Cruise Lines, Carnival Corp, is also conducting an operational review of its 10 brands and 101 ships - at an expected cost of $600 million to $700 million.
The reconfiguration of Triumph's engine room involved re-routing an extensive network of electrical cables that power the ship's propulsion and on-board hotel services, including cabin toilets, cooking facilities and air conditioning.
The February accident, which was the second major power loss on one of its ships in little more than two years, made negative headlines around the world as passengers camped out on deck without hot food or working toilets.
In November 2010, an engine fire on the Carnival Splendor crippled its propulsion system and knocked out most of its power while it was off the Pacific coast of Mexico.
The enhancement program also involves placing additional emergency diesel generators on the upper deck, and fire safety upgrades of all 24 ships in Carnival's fleet. That included upgrading the fleet's "water mist" fire suppression systems with the latest technology.
Carnival ships already have emergency generators designed to provide power to the ship's safety systems. The additional generators will allow Carnival to provide more essential hotel services, such as elevators, cabin toilets and cooking facilities, in the event of another loss of power.
The Triumph has since returned to its home port in Galveston, Texas, from where it departed for a four-day cruise to Mexico on Thursday.
Carnival Corp also operates the Holland America and Costa cruise lines.
Shares of Carnival closed up $1.20, or 3.67 percent, at $33.92 on Thursday.
(Reporting By David Adams; Editing by Steve Orlofsky)