The cruise ship that cut its voyage short after getting battered by rough seas and powerful winds during a storm in the Atlantic Ocean sustained damage to a key part of its propulsion system and officials are ordering it be fixed before the ship returns to sea for its next cruise this weekend, authorities say.

Royal Caribbean insisted for days that the damage to the Bahamas-bound Anthem of the Seas was "cosmetic" and "superficial" after it got caught in a storm off the Carolinas Sunday. The ship returned to its New Jersey port Wednesday, bringing back 1,600 crew members and 4,500 passengers, one of whom declared it a "cruise from hell."

Royal Caribbean said Wednesday that superficial damage to the 1,141-foot ship had been repaired and that the ship will resume its planned itinerary for next week's cruise.

But Coast Guard inspectors examined the ship after it docked back at Bayonne's Cape Liberty, four days after it departed, and they showed NBC 4 New York the wakes behind the ship: only the left propulsion system had powered the return voyage, they said.

"It's not functioning properly at the moment, and our team is on board working through that to make sure it's functioning property before it is allowed to leave," said Coast Guard investigator Lt. Josh Buck.

The news is worrisome to the thousands of people planning to depart on the Anthem of the Seas' next trip this Saturday, like Richie Traks, a photographer with NBC.

"My wife's been on the phone trying to get another cruise ship out of Florida, but it's last minute," he said.

It's a 39th-anniversary cruise for the couple, who have already scheduled their vacation for the week.

The Coast Guard said every important function of the ship is being examined, from lifesaving systems to structural integrity to fire suppression, as well as the propulsion system that kept the ship from returning at full speed.

The Coast Guard said it hopes it can be corrected by Saturday's sail date but the ship will remain docked in Bayonne until they know it's working properly. Technicians on the ship are replacing the burned-out clutches inside the propulsion system, and repairs and testing are ongoing, the Coast Guard said.

"At this time all repairs appear to be on track and all systems tests are progressing satisfactorily," the Coast Guard said in a press release Friday, adding that "the vessel will not be cleared to leave the port until all safety of life at sea requirements are met."

The Coast Guard said Friday night it was still awaiting final tests and inspectors will return Saturday morning to determine whether the ship can sail as planned in the afternoon.

Royal Caribbean has not responded to several messages requesting comment on the Coast Guard's statements.

Meanwhile, past and would-be passengers remain frustrated.

"All the technology we have these days, why would they sail into a storm?" Traks said.

Royal Caribbean has apologized, saying the storm far exceeded forecasts but the company would be strengthening its storm avoidance policy and adding resources at its Miami headquarters to provide additional guidance to ships' captains.

The National Weather Service's Ocean Prediction Center had issued an alert for a strong storm four days in advance. The first warning was issued Saturday for possible hurricane-force winds in the area the ship was scheduled to sail through.

One passenger told NBC 4 New York that the captain "did tell us in the beginning that we were going into bad weather but he thought he could get around it."

The captain asked passengers to stay in their cabins as powerful 120-mph sustained winds and waves as high as 30 feet tossed the vessel around beginning Sunday afternoon.

"Everything was blowing open, the closets were flying open, glass was breaking," said passenger Elaine. "It was a cruise from hell."

Royal Caribbean says four passengers reported minor injuries.

Passengers will get a full refund and a certificate toward 50 percent off a future cruise.

One man said he actually enjoyed the ride.

"It was so much fun, the rocking back and forth, we enjoyed it," said Randy Kuykendell of Atlanta. "Where else can you get a Disney cruise basically for free and then 50 percent off for the next cruise?"