In the eight and a half months of the life of the War Flight it had received fourteen flying-boats in all, five of which were still in good condition. With this small amount of material the pilots had carried out five hundred and fifty-four patrols, flown a distance of seventy-seven thousand and five hundred sea miles, brought a Zeppelin down in flames, sighted forty-four enemy submarines, and bombed twenty-five of them.
CHAPTER VI.
WINGED HUNS AND THE TALE OF THE I.O.
I.
Down in the Straits of Dover there was now in being a barrage which put the fear into the hearts of the crews of the German submarines.
All night long, across the narrow channel between the white chalk cliffs of Dover and Calais, a line of armed trawlers lit up the waves with brilliant flares, and prevented the U-boats from slipping through on the surface.
Beneath the water were nasty devices which, when encountered by an Undersea-boat trying to creep through submerged, brought its crew to a sticky end, and reduced the cunning mechanism of the submarine to scrap.
Between the coasts of England and France two cables were laid on the bottom, parallel to each other, and some distance apart. These cables had hydrophones on them at frequent intervals. A hydrophone is a water telephone. If a noise is made in the water, say by the twin propellers of a submarine revolving, the sound is picked up by the diaphragm in the hydrophone, which is similar to the diaphragm in a telephone, only, of course, bigger.