Divers enter sunken superyacht - but have just 10 minutes to search for bodies

British tech tycoon Mike Lynch and his 18-year-old daughter Hannah are among six missing after a luxury yacht sank in a tornado off the coast of Italy. One person has already been declared dead.

The British-flagged superyacht Bayesian is still largely intact on the seabed, but the 50m depth makes it difficult to access, and the time window divers have make searches is incredibly tight, according to one of those leading the effort.

Among those diving are two cave divers, who will have experience navigating through tight areas.

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"They can stay underwater for a maximum of 12 minutes, two of which are needed to go up and down," emergency responder Luca Cari told Italian daily Giornale Di Sicilia.

"So the real time to be able to carry out the search is 10 minutes per dive."

Divers have entered the lounge via a ladder and are now trying to find the best access point to enter the rest of the yacht.

Mr Cari explained how the divers had identified a glass window of the Bayesian from which they could enter, though it will first need to be removed in order to gain access. The window is 3cm thick, making removal difficult.

From the outside it is impossible to see inside the yacht, further hampering the search.

The rescue team already searched the command bridge, which "is full of electrical cables", but did not find anyone in the area.

"The spaces inside the sailing ship are very small and if you encounter an obstacle it is very complicated to move forward, just as it is very difficult to find alternative routes," he added.

Mr Lynch, known as the "British Bill Gates", has been in the headlines in recent months over a high-profile fraud case.

In June, he was cleared of all charges by a US jury related to the sale of his software company Autonomy to Hewlett-Packard in 2011.

His wife, Angela Bacares, was among the 15 people already rescued.

Among others said to be missing are lawyer Christopher Morvillo, a Clifford Chance partner and Mr Lynch's co-counsel in his US trial, Mr Morvillo's wife, Morgan Stanley International chairman Jonathan Bloomer, who is also chair of UK insurer Hiscox, and his wife Judy.

-SKY NEWS