The vessel was on a laden voyage to the Far East.During the last month, the 
crew had been inspecting the vessel's topside ballast tanks, noting condition of 
steel and paintwork.One OS was 
positioned on deck as
a guard and attendant, while the 2nd Officer and one AB were to inspect the 
tank.The 2nd Officer remained in the tank, while the OS remained on deck awaiting 
the AB's return.As the 2nd Officer entered the tank, he complained about the hot, damp air 
and that he could hardly see anything in the poor light of his torch.Entering the manhole to get a better view, he 
discovered the 2nd Officer lying motionless at the bottom of the tank.His first thought was 
to enter, but remembered previous advice about such accidents and rushed 
instead to raise the alarm.The Chief Officer took charge and ordered a set of breathing apparatus belonging 
to the fireman outfit to be brought forward, along with a rope and a stretcher.The OS 
regained consciousness when he was brought up to the deck but it wasThe crew was now about to inspect the last ballast tank, the 
no. 1 port.Three crew members were preparing to carry out the inspection.