Investigators examining the sinking of a luxury yacht off the coast of Sicily face a number of key questions.

Here the PA news agency identifies seven issues that inspectors of Bayesian may be focusing on.

-The design of the yacht

Bayesian has a mast measuring 72 metres, making it one of the largest in the world among sailing yachts.

Sam Jefferson, editor of the magazine Sailing Today, told the PA news agency the mast “acted almost like a sail” when severe weather hit the vessel, causing it to be “pinned over on its side”.

– Were windows and doors left open?

Mr Jefferson said he suspects “all the doors were open because it was hot”, causing the yacht to fill with water “very quickly”.

Weather records show temperatures reached around 33C the day before the sinking, which may have led to the vessel’s occupants keeping access points open overnight.

– Obtaining video footage of the sinking

The Italian coast guard has reportedly visited homes and organisations in the local area to obtain footage of the sinking from surveillance cameras.

One clip available online shows the boat being battered by severe weather before disappearing into the water.

– Interviewing survivors

Interviews with the 15 surviving crew members and passengers will be crucial to finding out what happened.

The ship’s captain, James Cutfield, has reportedly already been questioned by police for more than two hours.

– Was the keel a factor?

Italian media reported that divers found the Bayesian’s keel – a flat blade on the bottom of yachts that sticks down into the water to boost stability – was partially retracted.

Some yacht safety experts believe that may have contributed to the sinking.

But the Telegraph reported that a spokesperson for Italian Sea Group, which owns the company that built Bayesian, said: “Even without the keel completely out, the ship is stable and only a massive entry of water could have caused the sinking.”

– Will the yacht be salvaged?

Nick Barke, head of salvage operations at Boats.co.uk, a boat sales and services company, told PA that the “only real way of knowing” why the yacht sank will be to lift it to the surface, but that would be “expensive and complicated process”, likely to involve a crane barge.

He said divers would attach straps to the boat before it is lifted upright and then hauled out of the water.

He predicted this would be “time-consuming” as “they have to do it in such a way that they don’t damage anything too badly.”

– What is the UK’s role?

The Marine Accident Investigation Branch (MAIB) – a branch of the Department for Transport – has sent a team of investigators to the scene of the sinking, as Bayesian was British-flagged.

It will produce a report into why the sinking happened and may provide recommendations to prevent future occurrences.

The MAUB does not apportion blame.