By this time only five or six persons remained on board, the skipper being still on the bridge. Two boats had already pushed off. It was merely a question of minutes before the "Nordby" made her final plunge.
"What's that fellow up to, by Jove!" suddenly exclaimed Lieutenant Holloway.
Otto Oberfurst had mounted the main-mast shrouds and was gesticulating violently in the direction of an object broad on the port-beam. The object was a German submarine of the most modern type, running on the surface at a good eighteen or twenty knots.
The Danish skipper saw her too. Whatever his feelings were towards submarines in general, his action showed that he had no love for those sailing under the Black Cross Ensign—the modern counterpart of the "Jolly Roger."
He shouted an order. Three seamen sprang into the rigging and with no little force compelled the spy to descend. Not content with that, they bundled him unceremoniously into the last boat that was rubbing her gunwale against the "Nordby's" starboard side.
They were not feelings of humanity that prompted the German submarine to speed to the vicinity of the sinking ship. Slowing down within hailing distance, her officers and crew came on deck to gloat over the sinking of a helpless neutral merchantman. More than likely they were anxious to ascertain her name so that they could strengthen the claim for the award of Iron Crosses—the highly prized reward for "frightfulness" as practised by the degenerate descendants of Attila.
The Danish skipper enjoined strict silence. He had now jumped into the boat—the last to leave the stricken ship. Otto Oberfurst, lying at full length on the gratings, with two brawny seamen holding him down, was helpless to give another warning. In breathless silence they waited.
"Good!" ejaculated Tressidar as an ever-diverging feather of ripples marked the track of a 24-in. torpedo. Passing within fifty yards of the boat in which he sat, the deadly weapon sped unerringly towards its quarry.
Amidst a tremendous upheaval of water, mingled with smoke and fragments of metal, the unterseeboot vanished for ever; while like a huge whale the British submarine that had dealt the fatal blow shook herself clear of the water.
The appearance was little more than momentary, for without checking her way the vessel dived again and was lost to sight.