Passengers are confined on the cruise ship Ambition, pictured at Bordeaux harbor on Wednesday, following the outbreak of a gastrointestinal illness onboard. - Ugo Amez/SIPA/AP As many as 1,700 passengers are being held on board a cruise ship in southwest France, after dozens of cases of possible gastroenteritis on board. The ship, named Ambition, was scheduled to sail around France and Spain after picking up passengers from the UK cities of Belfast and Liverpool on May 8 and May 9.