Royal Caribbean is almost ready to bring back into service one of its mega ships, but it needs a few more days to solve a propulsion problem.

Local media reports that Allure of the Seas' departure from Cádiz, Spain, has been delayed. To be clear, there's been no announced delay from the cruise line in the start of the first sailing back for Allure of the Seas.
The Oasis Class ship was scheduled to depart from Cádiz on Monday, April 7, before her post-revitalization debut on the 11th.
However, during her time at Navantia's dry dock, a technician discovered that several propellers on the three azipods, the electronic propulsion systems attached to the ship's hull beneath the waterline, were in poor condition.
They didn't need to be replaced; however, Royal Caribbean opted to add new propellers to Allure before sending her to Barcelona to start a busy seasonal stint in the Mediterranean — her first since 2015.

Diario de Cádiz reported that the issues could keep Allure in Cádiz for three extra days. However, Navantia and the auxiliary companies reduced the estimated timeline to a day and a half if there aren't further complications.
According to Bryan James, a musician onboard, Allure of the Seas just left the dryock this evening, "We are leaving the shipyard and heading to Barcelona! "
Replacing the propellers isn't cheap. While Navantia hasn't released the price, Diario de Cádiz revealed it could cost €2 or €3 million (approximately $2.2 - $3.3 million). This is on top of the $100+ million spent on the scheduled renovation.

Passengers booked on Allure of the Seas' April 11 cruise to Marseille and Palma de Mallorca haven't been informed of any changes to their itinerary, though this could change depending on when Allure finally departs.
Allure of the Seas has spent over five weeks in Spain undergoing a massive renovation to bring her up-to-date with amenities like Playmaker's, the Perfect Storm water slides, Ultimate Abyss, the Mason Jar specialty restaurant, resort-style pool deck, new Ultimate Panoramic Suites, and more.
The updates were initially scheduled for 2020; however, her much-needed revitalization was indefinitely delayed because of the pandemic. Details regarding the dry dock were finally announced last August.
Read more: Royal Caribbean ship classes ultimate guide

Over 2,300 contractors — including electricians, carpenters, painters, and plasterers — have been working hard to ensure that every new feature is ready, as reported by The Independent.
In addition to new amenities, the crew has spent time refreshing existing spaces. For example, over 28,000 bulbs have been replaced in cabins with more energy-efficient LED lighting.
Moreover, thousands of cracked or worn tiles in the outdoor Central Park neighborhood on Deck 8 have been replaced, as well as the mini-golf turf on Deck 15.

Following the scheduled 4-night cruise on Apr. 11 and 5-night cruise on Apr. 15, Allure of the Seas will offer weeklong Mediterranean voyages through October 2025.
Guests can depart on round-trip itineraries from either Barcelona, Spain, or Civitavecchia (Rome), Italy. Ports of call include Palma de Mallorca, Spain; Marseille, France; La Spezia, Italy; and Naples, Italy.
Allure of the Seas will return to North America, offering winter cruises to the Caribbean from Fort Lauderdale, Florida.