The trawlers at the corners got out their sweeps—long wire hawsers, with a heavy "kite" in the center to keep their bights down on the seabed—and commenced to steam toward each other.
As the pairs of vessels met, their wires simultaneously engaged themselves under the U-boat's bow and stern, and commenced to work their sinuous way between her hull and the sea bottom.
Then the strange thing happened. Two round, black objects seemed to detach themselves from her hull and float surfaceward, to hover a second and then to commence bobbing down the tide.
"Minelayer, eh?" called the seaplane's observer.
"That's it, lad," came the telephoned answer, "but her eggs can wait for a minute."
Then the trawlers crossed their dependent cables and thus held the U-boat in a kind of wire cat's cradle. She seemed to suddenly awake to her danger, for with a bound she tried to disentangle herself from the meshes which held her. But it was no use; the trawlers had been too at the game and the submarine was doomed.
"Got him," signaled the seaplane. "Thanks," responded the destroyer. "We'll give him five minutes to come up and breathe, but no longer." That time passed but still Fritz made no further move.
The End of the U-Boat.
At a flag signal from the destroyer the port-frigate, the port-frigate, and the starboard after one clipped a small red tin of high explosive to the bar-taut wire, and allowed it to slide down till it touched the U-boat's hull.
It was the  Seaplane's turn to wave a flag, and immediately there followed the fall of two fists upon two firing keys; the uprising of two gray mounds of water and a rumbling, muffled explosion. 