Carnival Corp., whose customers suffered through a high-profile nightmare cruise in February, said it will spend between $600 million and $700 million to upgrade its fleet’s power systems.

Earlier this year, a fire aboard the Carnival Triumph caused the ship to lose power in the middle of the Gulf of Mexico. It took five days to tow the ship to shore. During the ordeal, passengers said raw sewage from non-working toilets was sloshing through hallways and running down the walls of the cabins. They also reported stifling heat due to loss of air conditioning and limited food availability. A month later, another ship lost power when it was docked in the Caribbean, and Carnival had to fly all of its passengers home.