‘2 and 3 out, sir,’ said Hoskins.
The captain left the periscope and went up the dark shaft of the conning-tower hatch. Very gingerly he eased the strongback, and there was a rush of escaping air as the pressure was released from the boat.
Seagrave had his eye on the barometer, which had swung round while diving to ‘off the map,’ and was now rapidly decreasing to the external pressure.
‘One inch!’ he shouted up the hatch. ‘Equal!’
The men could feel the change in the atmosphere by a tickling sensation in the ears, much like having a drop of water in them. Raymond threw open the hatch and stepped out, followed by Boyd.
Up here the sunlight struck sharply on the eyes. In this trim the boat was half submerged and looked like some water-logged hulk wallowing on the surface. She dripped at every pore, and the calm sea washed sluggishly over her superstructure.
Three minutes later the sun crossed, and they were down again, Raymond closing the hatch behind him as he descended.
‘Flood main ballast,’ he ordered.
Once more the tanks filled, the Kingstons were closed, and in less than sixty seconds she was down to thirty feet again.
Ten minutes had sufficed for the whole business.