The first paying passengers on the world’s biggest-ever cruise ship have complained that it is a £783 million ‘building site’. Harmony of the Seas left Southampton for Rotterdam on a four-night cruise on Sunday, but customers have complained about closed attractions, building work and even debris in the pools. Passengers took to Twitter to complain that the ship is “not ready”, and spoke of “queues of complaining guests and distressed families” and even “sharp debris in the children’s pool”. Another wrote, “Really not pleased work is still going on when they have over 6,000 passengers.” A Royal Caribbean Cruises spokesman confirmed the trip was not a “shakedown cruise”, during which a ship’s systems and facilities are tested. “Whilst the majority of the ship’s features are open and already being enjoyed by thousands of guests, as with any new build, we are still making some final finishing touches,” he told the BBC. “These early sailings were made possible due to the early delivery of the ship and we hope this has been reflected in the great value offering guests secured for their holiday.” The gigantic 227,000-ton Harmony of the Seas is 216ft wide and, at 1,187ft in length, 164ft longer than the Eiffel Tower is tall. It has room for 8,500 passengers and crew, a 10-storey slide and robot barmen. It cost almost $1 billion to build, has 16 decks and will be able to carry 6,360 passengers and 2,100 crew members. The immense floating town has 16 decks and will be able to carry 6,360 passengers and 2,100 crew members. The ship was built by the STX France boatyard in Saint-Nazaire on the Atlantic coast RCCL already operates two giant sister liners to the Harmony of the Seas called Allure of the Seas and Oasis of the Seas. They are only marginally smaller than the new ship. Among the onboard attractions are “The Ultimate Abyss”, a 10-storey slide from the top deck to the boardwalk which RCCL bills as the world’s biggest ship-mounted slide. The purple slide can be clearly seen at the rear of the ship. A giant climbing wall, a rope slide, mini-golf, surf simulator, floating Jacuzzis, casino and 1,400-seat theatre playing Broadway musicals are among the other attractions. Two robot barmen will serve passengers in the “Bionic Bar”. The ship even has its own high street, and a “Central Park” deck featuring 11,000 plants. After its maiden voyage, it will dock in its new home port of Barcelona a week later, after which it will begin regular cruises through to late October. It took 2,500 workers at STX France a total of 10 million work-hours to complete the enormous vessel after work began in September 2013. The contract marked a major boost for the boatyard after several lean years. STX has built 120 cruise ships over its 150 years, and has another 11 lined up for the next decade. RCCL has already ordered another sister ship of the Harmony to join its fleet in 2018.