[Illustration: "THE SUBMARINE WAS NOW IN AN AWKWARD PLIGHT">[

The whaler was now a hundred yards off, and the cutter lay between her and the still submerged U-boat. Haynes had heard the double report of the revolver shots, and was at a loss to account for Webb's seemingly inexplicable act.

"Come alongside as hard as you can!" shouted Webb; then addressing the bowman of the cutter he ordered: "A couple of hitches with your painter, man."

The bowman acted promptly. In a few seconds the cutter had swung round and was being urged at a steady rate through the water with her painter made fast to the foremost of the damaged periscopes.

Haynes, too, had now grasped the situation. The whaler, urged at the greatest speed by the rowers, was quickly on the spot. Her painter was then secured to the aftermost periscope.

The two Subs were now keenly on the alert for further developments. The point to consider was whether the U-boat would attempt to continue to ascend, or make a frantic effort to submerge completely. In the former case both boats would have to be trimmed by the head to counteract the lifting power of the invisible submarine; in the latter case all hands, with the exception of the bowman, would have to crowd aft in order to impart the greatest buoyancy to the for'ard portion of the boats.

The submarine was now in an awkward plight. In spite of the fact that her displacement was something in the neighbourhood of six hundred tons she had little reserve of buoyancy, represented by the weight of water in her ballast tanks. Against this she was hampered by the two boats, the cutter weighing a little over a ton without her crew and gear, and the whaler supplying a dead weight of nearly half that of her consort.

The U-boat dare not rise. To do so, even if she were capable of the fact with the two "millstones" literally hanging round her neck, she would be running an unknown risk, since she was unaware of the nature of the obstruction. Nor could she dive with safety. Before she could admit sufficient water ballast to make her heavy enough to swamp the two boats, the strain would wrench the periscopes from the submarine's hull. In spite of the intricate valves, the wrench imparted to her mechanism would make it an impossibility to prevent quantities of water entering the interior, and send the U-boat down for good and all.

"We've got her, old man!" explained Haynes joyously.

"And she's got us, too," replied Webb. "Sort of marine game of beggar my neighbour."