"Up with your anchor," whispered the pilot, "before he shuts off his power."
His companion leaned stealthily over the side and rapidly paid in the rope, lifting the light anchor over the gunwale and cautiously stowing it in the bottom. And he was none too soon. Hardly was the anchor aboard before the roaring sound ceased and the oncoming boat approached with lessened speed. But the scouts' boat rode free, ready for instant work.
"Down with you," whispered the pilot. "Keep your heads below the gunwale till they're past."
The party crouched lower. On came the spy boat. Its muffled engine beats were hardly louder than the pounding of the hearts that watched. It drove steadily forward. Now it was a few fathoms astern. Now it was abreast. Now it had passed. Stealthily four heads slipped above the gunwale of the scout boat. The spy craft was already lost in darkness. The pilot grasped his wheel. He turned a switch and the boat began to vibrate silently. Then it moved forward, gathering momentum with every second. Under the covered deck the other agent flashed a light on his watch.
"Eleven fifty-eight," he whispered. "They figured it down close."
On went the boat. The craft ahead of them was still invisible though but a few hundred feet distant. But by peering sharply at the water, the pilot could see where it had passed. The surface was still agitated. Faintly came the sound of the muffled motor. The pilot increased his speed, but no sound came from his boat. Like a ghost it glided through the dark waters.
"Look sharp," whispered the pilot. "Let me know if you see them. We've got to get as close to them as we can, and yet we must not be seen."
On went the spy craft. It slid past the park. The street leading to that was faintly illumined by occasional lights.
The pilot uttered a low exclamation of alarm. "If they look back," he whispered, "those lights will betray us. We're right between them and the spies."
Sharply he swung his craft to the right, crowding close to the shallow waters that edged the channel. If he ran into the mud flats disaster might result. But to stay where they would be silhouetted against the street lights was to court discovery. He had chosen the lesser of two evils.