The engineer was in his cockpit in the middle of the boat, surrounded by the petrol-tanks, a maze of piping, and innumerable gadgets. His duties were to keep an eye on the engines, see that the water in the radiators did not boil, and take care of the petrol system.
Two wind-driven pumps forced the petrol up from the main tanks to a small tank in the top plane. The engines were fed from the top tank by gravity, and the surplus petrol pumped up ran back to the main tanks. The engineer regulated the flow so that the petrol was drawn from and overflowed back into the main tanks in such a way that the fore-and-aft balance of the boat was maintained. If anything went wrong with an engine he had to climb out on the wing and, if possible, make a repair.
Once a flying-boat attacked a submarine from a low altitude and was met by machine-gun fire. A bullet drilled a hole in a radiator, and the water began to run out. Also the first two bombs dropped missed the submarine. The engineer quickly climbed out on the wing and put a plug in the hole, and held it there, while the pilot took the boat over the submarine again, and destroyed it with the second two bombs. The engineer held the plug in place until the boat landed in the home harbour.
All four members of the crew were now in their places. The working party attached a stout line to the rear of the trolley, knocked away the chocks, and rolled the boat out on the slipway to where it began to slope down into the water. Here six waders, in waterproof breeches coming up to their armpits, and weighted boots to give them a secure foothold when the tide was running, took charge, and steered the boat down into the water, the working party easing her down by tailing on the line.
A wader has not got a soft job. At some stations where there is a strong tide running waders have been washed off the slipways and drowned.
As the flying-boat entered the water the trolley, being heavy, remained on the slipway, and the boat floated off. The thrust of the engines urged her forward, and she taxied clear. Hobbs taxied out into the harbour, turned up into the wind, and opened the engines full out.
Driven by seven hundred tearing horse-power, the boat ran along the water with ever-increasing speed, a big white wave bursting into spray beneath her bow. As the speed increased, the boat was lifted on top of the water by her hydroplane step until she was skimming lightly over the surface. The air speed-indicator was registering thirty-five knots. Then Hobbs pulled back the control wheel, and the boat leaped into the air, the air speed jumping to sixty knots. Climbing in a straight line until he was at a thousand feet, he turned the bow of the boat out to sea.