The operators of a cruise ship that sank in April, killing two passengers, blamed an error in official maps yesterday for the accident off the Greek island of Santorini. The Sea Diamond hit rocks off Santorini on April 5 and sank hours later. Some 1,600 people, mostly American tourists, were evacuated from the ship, but two French passengers were never found and are presumed drowned. Operator Louis Hellenic Cruises said it commissioned a seabed survey of the accident area and found that rocks hit by the ship were not marked on official charts. «The ship’s captain maintained a distance of 130 meters from the shore and should have been 57 meters clear of the rocks. But something very different happened,» said George Koubenas, the company’s head of operations. Asked why no other ship trying to moor at the busy island had struck the reef, Koubenas said every cruise ship’s approach was different. Company lawyer Giorgos Iatridis-Ramadanis said the new finding did not affect insurance payments as Louis had already collected the insurance for the accident.