“It was part of the classified propulsion upgrade we installed three weeks ago.”

Hayes stared at me, his brow furrowed in the dim light.

“The Navy blue prints don’t show any secondary valves in this sector,” he said.

“Because they aren’t Navy standard,” I said.

“They’re civilian prototypes. I designed them myself.”

I pointed toward the small, raised housing just aft of the sail, half-submerged in the rising tide.

“The auxiliary bypass valve is located under the deck grating, near the secondary hydraulic manifold,” I explained.

“If we can reach it, we can manually override the computer’s command to vent.”

“Can we turn it from out here?” Hayes asked.

“No,” I said. “The access panel is inside the dry-deck shelter trunk.”

“But that compartment is already taking on water.”

“Then we have to go in before the pressure seals the outer hatch permanently,” Hayes said.

He reached down and unclipped a heavy steel flashlight from his belt, clicking it on.

The bright LED beam cut through the mist, illuminating the swirling black water around the hatch.

“Tell me exactly what I’m looking for,” he said.