An inquest has been opened into the deaths of two men in a disused fuel tank in north Suffolk.
Crews worked late into the night to retrieve the bodies
Welders Charles Buckenham, 52, of Hardy Close, Lowestoft, Suffolk and his stepfather Brian Dove, 55, of Butt Lane, Burgh Castle, Norfolk, died at Oulton broad last week.
They had been dead for a number of hours by the time emergency services managed to reach them on 5 March.
The inquest was opened on Tuesday.
The men were working for the marine engineers Small and Co at Lake Lothing, Oulton Broad in Suffolk.
It is thought one man went into the tank to look at it, but did not come out.
Seven hours to retrieve bodies
The second man called for an ambulance before going inside himself at about 1430 GMT on 5 March.
A spokesman for the East Anglian Ambulance Service said they were already too late when they arrived at the quayside at Lake Lothing.
It took emergency services seven hours to retrieve their bodies.
The search of the five meter by 15 meter tank was hampered by water and slurry.
Suffolk Police said they were treating the deaths as an industrial accident.