Jimmy Mowlam, 63, said his 37-year-old son, Rob Mowlam, told him by phone Monday night that the lack of ventilation onboard Carnival Cruise Lines’ Carnival Triumph had made it too hot to sleep inside. He said Rob and his new bride — they got married onboard Saturday — are among the many passengers who have set up camp on the ocean liner’s decks and in its common areas.

“He said up on deck it looks like a shanty town, with sheets, almost like tents, mattresses, anything else they can pull to sleep on,” said Mowlam, 63, who is from Warren, in southeast Texas. His son is from nearby Nederland.

The ship left Galveston, Texas, for a four-day cruise last Thursday carrying 3,143 passengers and 1,086 crew members. On Sunday, the ship was about 150 miles off Mexico’s Yucatan Peninsula when an engine room fire knocked out its primary power source, crippling its water and plumbing systems and leaving it adrift on only a backup power.

There were no reported injuries caused by the fire, but Carnival spokeswoman Joyce Oliva said Tuesday that a passenger with a pre-existing medical condition was taken off the ship as a precaution.

Everyone else will likely have to remain onboard until the ship reaches Mobile, Ala., which is expected to happen Thursday, weather permitting.

Besides the two tugs, at least two other Carnival cruise ships have been diverted to the Triumph to leave supplies and a 210-foot Coast Guard cutter was at the scene, Coast Guard Petty Officer Richard Brahm said Tuesday.

“If they do need any help, we’re there,” he said.

Mowlam said his son told him there is no running water and few working toilets and passengers were given plastic bags to “use for their business.”

“But so far people have been pretty much taking it in stride,” Mowlam said his son told him.

Rob Mowlam told his father the ship’s crew had started giving away free alcohol to passengers.

“He was concerned about what that was going to lead to when people start drinking too much,” Mowlam said.

Other passengers have described more dire conditions, including overflowing toilets and limited access to food.

Texas resident Brent Nutt, whose wife is on the cruise ship, said Monday that she told him the “whole boat stinks extremely bad” and some passengers were getting sick and throwing up. Nutt said his wife reported “water and feces all over the floor.”

Carnival hasn’t determined what caused the fire or how it caused the electrical problems that have crippled the ship’s water and plumbing systems, said Oliva, the company spokeswoman.

The National Transportation Safety Board announced Tuesday it has opened an investigation into the cause of the fire. The NTSB said the Bahamas Maritime Agency will lead the investigation because the ship carries a Bahamian flag.

The ship was originally going to be towed to the port in Progreso, Mexico, but after currents pushed it northward, a decision was made to take it to Mobile to make it easier for passengers without passports to get home, the company said.

A similar situation occurred on a Carnival cruise ship in November 2010. That vessel was also stranded for three days with 4,500 people aboard after a fire in the engine room. When the passengers disembarked in San Diego they described a nightmarish three days in the Pacific with limited food, power and bathroom access.

Carnival said in a statement that it had cancelled the Triumph’s next two voyages scheduled to depart Monday and Saturday. Passengers aboard the stranded ship will also receive a full refund, the statement said.