Visibility in the Danube has been described as 'practically zero' with Hungarian officials saying it is 'impossible to get close' to the Mermaid on the riverbed 20ft below the surface. Such is the strength of the current, there are fears some of the missing victims could already have drifted as far as Serbia, more than a hundred miles to the south, and hopes are fading that anyone else will be found alive. The 89ft sightseeing vessel, which was carrying 35 including more than 30 South Korean tourists, was struck from behind by the 440ft Viking Sigyn 'floating hotel' (bottom right) outside the city's parliament building during a fierce rainstorm and flipped over (top right) in just seven seconds. Just seven were pulled alive from the freezing water while seven people have been confirmed dead. The captain of the Viking Sigyn, identified only as Yuriy C, 64, has been arrested by police, who suspect him of 'endangering water transport leading to a deadly mass accident'. Left: Divers attempt to reach the submerged boat.