A man who died after falling overboard while working on a scallop dredger is likely to have survived if he had been wearing a life jacket, marine accident investigators have concluded.

Deckhand Scott Rennie, 31, was on the King Challenger vessel 12 nautical miles south-west of Scalloway, Shetland, when he fell overboard while trying to unhook a damaged dredge bag from the end of the tipping door.

He was brought back on board in less than ten minutes but was unconscious and showed no signs of life.

The crew were unable to resuscitate him and despite quick air evacuation to hospital, he did not survive.

The Marine Accident Investigation Branch (MAIB) found he fell into the sea with a temperature of 10.5C and although a good swimmer he was incapacitated after four minutes.

The report into the accident, on June 23, 2016, described how his workmates tried to save him once rescued from the water.

It said: "The crew laid Scott on the deck and took turns to give him chest compressions. He was not breathing, his lips were blue, his eyes were fixed open and he was frothing at the mouth.

"Rescue helicopter R900 arrived at the scene at 10.07am and by 10.15am a winchman had landed on board.

"Scott was airlifted to Lerwick from where he was transferred by road to Gilbert Bain Hospital. He did not recover consciousness and was declared deceased at 11.00am."

The MAIB said crew on the vessel regularly worked on open tipping doors without securing themselves with a lifeline or wearing a life jacket.

It also said they were "unprepared for the rescue of an unconscious casualty" from the water.

Mr Rennie was 20 metres from the stern of the dredger trying to swim towards it when he was thrown a lifebuoy but he was unable to reach it.

Despite the reservations of the skipper, one of the deckhands donned a life jacket and jumped into the water to put a harness round Mr Rennie, who was then floating on his back unconscious.

He was then brought aboard the vessel.

The report said: "The post-mortem examination report stated that Scott died as a result of drowning."

Accident investigators said the vessel's risk assessments should have recognised that walking on the tipping doors was "unsafe" and identified alternative working practices.

It added unless realistic "man overboard" drills are carried out, the crew's reaction will be ad hoc, risking delays in recovering a casualty and potentially resulting in additional casualties.

Mr Rennie, the report concluded, "succumbed to the debilitating effects of cold water incapacitation" within approximately four minutes of falling into the water.

It added: "Had Scott been wearing a life jacket when he entered the water, it is likely that he would have been recovered alive."