The sea-plane had dropped two bombs, both of which very nearly attained their object.

Kapitan Schwalbe did not bring the submarine to a horizontal position until she had reached a depth of fifteen fathoms. At that depth he was safe, both from explosives dropped from the sea-plane and also from observation. The water being still agitated, made it impossible for the observer on the biplane to follow the movements of a dark shadow fathoms deep. For once, the rough seas had been kind to U75; but the fact remained that she was still badly in want of fuel, while his last attempt had resulted in the loss of an officer and six men, who could not well be spared.

Although the sea-plane had failed to achieve her object by pulverizing the U-boat's hull, the moral and material result was none the less effective.

The explosion of the bombs had started several of U75's plates. Numerous jets of water were spurting through the seams, the inrush requiring all the mechanical appliances at the command of the modern pirate to keep the leaks under control, while the badly-jarred nerves of Kapitan Schwalbe and his crew warned them of the grave risks they ran in attempting to try conclusions with even an apparently harmless craft displaying the Red Ensign of Britain's Mercantile Marine.

CHAPTER IX

The Landing at Port Treherne

"I wonder if they'll let us go on deck," remarked Vernon Haye. "If so, I vote we have a shot at getting ashore. What sort of show is Port Treherne?"

"I know it fairly well," replied Ross. "It's the most forsaken crib you are ever likely to meet along the coast. It's a deep gully in the cliffs. There's only one small landing-place—a flat rock. Years ago there used to be a tramway down to the rock, and they shipped copper ore by means of derricks into lighters, which were towed across in fine weather to Swansea. But the mine closed down, the village is now deserted, and I don't believe there are any fishermen there. They say that the stream that flows into the port is still heavily charged with mundic. At all events the water is of a bright-red colour for several hundred yards from shore, and no fish will stick that."

It was close on the midnight following the disastrous attempt on the part of U75 to capture the oil-tank. The submarine was running awash, proceeding very slowly and cautiously towards Port Treherne—Station 41 of the secret petrol depots established by German agents along the coast of the British Islands.