It was the rare occasion where a life jacket wasn’t going to save your life, according to an investigation.

A UK teenager drowned during a horrific boating incident, in which her automatic life jacket prevented her from escaping a capsized pleasure cruiser. The freak incident occurred on May 25, 2020, but the manner in which she died was detailed in an accident report published Thursday.

"Without doubt, the wearing of personal flotation devices, such as lifejackets, saves lives," reads the statement in the probe from the Marine Accident Investigation Branch.

"However, there are circumstances when wearing automatically inflating lifejackets can be hazardous, for example, when in enclosed spaces such as accommodation areas and cabins."

BRTISH CONSERVATIVE POLITICIAN'S STABBING DEATH DECLARED A ‘TERRORIST INCIDENT’

Per the report, Gillian Davey, 17, was on a pleasure cruise with her family off the Cornish coast when their pontoon boat, the Norma G, was "capsized by a large wave" near the notoriously treacherous Doom Bar sandbank, according to Cornwall Live. Upon realizing their predicament, Gillian and her mother Carolina donned their personal flotation device, which inflated automatically when the cabin started filling with water.

And while Carolina removed her life vest and swam out of the cabin window to safety, her daughter kept hers on and became trapped in the submerged room as a result.

Meanwhile, Gillian’s father, Stefan Davey — who has was steering the ship — and his son, had been tossed overboard when the wave hit. They were later rescued by a passing harbor patrol boat along with Gillian’s mother.

According to the report, Stefan had tried several times to reach down and rescue his daughter, but was unable to do so due to the rough waters and the fact that the vessel had "inverted and sunk by the stern."

A lifeboat eventually arrived and managed to hoist the upended pontoon out of the water, so that Stefan could pull open the door and drag his daughter out. However, by that point, Gillian was unconscious and not breathing.

The teen was subsequently rushed to Royal Cornwall Hospital, where she was pronounced dead.

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Authorities have attributed the tragic incident to the father’s "limited boating experience."

"This sad accident highlights the need for leisure boat users to get properly trained and equip themselves with the necessary navigational tools to stay safe," said Captain Andrew Moll, MAIB’s Chief Inspector of Marine Accidents. "Conditions at sea can change rapidly, boat owners should check the weather forecast before setting out and know the limitations of their boat."

Click here to read more on the New York Post.