A photo of the ill-fated Bayesian superyacht which was taken minutes before it sank appears to show that a door on the vessel was closed, after claims it had been left open.

The snap, taken by a passenger on board a neighbouring yacht, contradicts allegations that the crew mistakenly left a door open and allowed water to flood the boat.

It was taken 14 minutes before the Bayesian went down during a freak storm off the coast of Sicily - killing seven people, including the British tech tycoon Mike Lynch and his 18-year-old daughter Hannah.

Three crew members are being investigated by prosecutors in Sicily after they were accused of leaving the large door open on the rear port side of the 56-metre yacht.

The flooding is alleged to have started after fierce winds and waves drove water through the door in the hull.

However, two photographs - which are set to be published in an ITV documentary broadcast on Thursday - appear to show the door shut in the hours and minutes leading up to the sinking. 

Passengers on board the the Sir Robert Baden Powell, a yacht that was anchored about 100 metres from the Bayesian, took the photos.

Karsten Borner, the Dutch captain of the Sir Robert Baden Powell, supplied the photos for the documentary and told German newspaper Der Spiegel that he was irritated by repeated attempts by the ship's builder to pin the blame on the crew. 

His frustration came after Giovanni Costantino, owner of the Perini Navi company which built the Bayesian in 2008, described the yacht as 'unsinkable' and claimed the crew must have left doors or hatches open, allowing water in.

The head of the Italian Sea Group blamed the crew for not saving the seven people who died, stating: 'If all 20 had been on deck, with lifeboats in the water, the yacht would have gone down, but all 20 would have been saved.'   

Borner and his crew picked up 15 survivors from the sinking yacht, including nine crew members and six passengers. 

Interviewed for the ITV documentary — The Sinking of a Superyacht — How Safe Is Your Voyage?, he recalled the traumatic moments: 'My first mate said, 'she has gone, she has sunk', and I was laughing at him, saying such a big thing doesn't disappear in a minute. He was right.' 

Italian firefighter Fabio Paoletti, who dived into the water to help find the bodies on board, said the hardest victim to find was Hannah Lynch. 

'The girl was at the end in the last room. She was of small stature and hidden by a mattress, so it took longer to see her,' he said.

Buoyancy balloons or a crane on a barge are expected to be used to raise the Bayesian, with plans expected to be finalised in the coming weeks.

Salvage expert Bertrand Sciboz, said he thought the second option was possible, with the cost running to over €2 million.

'You would need a big barge and put slings under the hull of the Bayesian and you salvage it very slowly with a big crane on the barge,' he said, adding: 'You have to be very careful to keep it intact.'