“Under it,” growled Donald Darbee. “They cut a well in the middle of the barge for the conning turret.”

“You saw that?”

“No. But how else could they get in and out?”

The launch captain glowered at Isaac Bell. “Mr. Bell, I predict that my boss is going to be talking to your boss, and neither of us is going to be very happy about it.”

“Let’s get closer,” said Bell.

“There isn’t enough water there for a Holland submarine.”

“It’s plenty deep,” Donald Darbee retorted quietly. “The tide scours the bank on this side.”

The helmsman called for Dead Slow, and drew within fifty feet.

The Van Dorns, the scowmen, and the harbor police peered into the murky water. The launch drifted closer to the car float.

“Lot of mud stirred up,” Darbee muttered worriedly.

“Our propeller’s stirring it,” said the captain. “Told you it’s too shallow.” To the helmsman he barked, “Back off before we run aground.”

Darbee said, “There’s thirty feet of water here if there’s an inch.” “Then what’s causing that mud?”

“That’s what I’m wondering.”

“So am I,” said Isaac Bell, peering into the water. Bubbles were rising from the murk and hissing on the surface.

Chapter 52

52

BACK AWAY!” ISAAC BELL SHOUTED. “BACK! FULL ASTERN.”

The helmsman and the engineer had quick reflexes. They reversed the engine in an instant. The propeller churned backward. Smoke and steam shot from the short stack. The boat stopped. But before it could gather way in reverse, a gray malevolent form rose swiftly under it.

“Grab ahold!”

Bell saw a pipe emerge just ahead of the launch—the periscope, a tube of angled mirrors, the submarine’s eye. A squat round turret broke the surface, the conning tower, rimmed with handrails. Then a mighty blow from underneath smashed into the bottom of the police launch and pushed its forty-foot hull out of the water. Its keel shattered with a loud crack of splitting wood, and still the police boat rose, lifted by a powerful steel hull that broke the surface like a maddened sperm whale.

The police launch fell onto its side, spilling Van Dorns, cops, and scowmen into the Kill.

Bell jumped onto the steel hull and waded through waist-deep water to the conning tower. He grabbed the handrails that surrounded the hatch on top and reached for a wheel that would open the hatch.

“Look out, Isaac!” Archie Abbott yelled. “He’s going under!”