Cutting Off the Flow
Long Tian sat on the deck for a moment, mentally reviewing the flow-cutting plan the man at the stern had described. The energy flow inside the pipe was transmitted upwards from the bottom; to cut it off, a point inside the pipe that could be blocked would need to be found, or the supply would need to be cut off from the outside. The duct he had seen behind the low door had a continuous upward flow of light on its inner wall, leading from the bottom to the bottom of the pavement. If there was a valve or latch at the bottom of the duct that could be closed, the flow could be stopped at its source.
He re-fastened the leather bag, re-tied the rope around his waist to the iron ring on the hull, and flipped into the water. This time, he entered the bottom cavity through the gap, walked to the low door of the tube, reopened the door panel, and squeezed sideways into the tube. The light stream on the inner wall of the tube illuminated his entire body after he entered. The light stream continuously surged up from the bottom, was partially cut off near his body, and the rest circled around to the sides and continued upward. He placed his palm on the inner wall of the tube to feel the temperature and speed of the light stream, confirming that it was a layer of continuously pushed energy, with uniform density, stable pressure, and no pulses or fluctuations. He squatted down inside the tube and felt downwards along the direction of the inner wall of the tube. Near the bottom, he felt a point on the inner wall above. A different structure—the inner wall of the catheter narrows slightly here, forming a ring-shaped convex edge, inside which is embedded a rotating ring-shaped clamp. The clamp has a groove on its surface, seemingly designed to be twisted with a tool or turned by hand. He inserted his finger into the groove and pushed along the circumference of the clamp. The clamp rotated a short distance under the force, and as it rotated, the brightness of the light flow on the inner wall of the catheter began to decrease, and the flow rate slowed down. He pushed it a little further, and the clamp continued to rotate. The light flow changed from a bright, continuous surge to a dim, slow overflow, stopping completely when the clamp was fully rotated. The light flow inside the catheter extinguished after the clamp closed completely, and the inside of the catheter fell into a state of continuous silence.
Long Tian stood silently for a moment, feeling the surrounding vibrations gradually subside. They didn't disappear immediately after the cut, but rather, like a machine whose power source had been shut off, continued to run for a short time due to inertia before slowly reducing their frequency and amplitude, eventually falling completely silent. He waited inside the conduit for a while longer, confirming that the vibrations had completely stopped, then swam upwards along the inside of the conduit to the low door, stepped out of the conduit, and closed the low door again. As he walked back to the exit at the edge of the crack in the bottom cavity, he noticed that the fine debris on the floor of the bottom cavity had stopped increasing after the cut, and the layer of debris on the ground remained in the same state as before the cut.
He surfaced through the crack, climbed back onto the boat, and knelt by the gunwale to wipe the water from his face. Yu Jin handed him a dry cloth, which he used to wipe his face and hair. He then sat down on the deck and briefly explained the process of closing the flow and the internal structure of the pipe. After listening, the person at the stern asked, "Can the clamps be opened again after they're closed?"
"Yes. There's room for rotation on both sides of the groove in the clamp; you can push it back to its original position. But when I pushed it just now, I didn't feel any resistance to it getting stuck, which means its structure hasn't become jammed from long-term use. If you want to restore it later, you can just open it again."
The person at the stern nodded, released the rudder from its fixed position, and slowly turned the ship back along its original path. Long Tian sat on the deck, took out the silk map from his leather pouch, and marked the location of the pipe interception and the direction of the clamp operation on the edge of the keel base section. He then drew a very faint mark on the blank space of the paper with his fingernail, indicating the method to restore the energy flow. After finishing, he put the map away and returned it to his pouch. He squatted down at the bow, watching the debris still floating on the sea. The peeling had stopped after the cut, but the detached fragments would continue to drift in the current for a while until they were dispersed to more distant sea areas.
On its return journey, the boat passed the edge of the shallow waters. Floating debris was pushed aside as it passed, only to gather again behind the stern. The people at the stern steered the boat back to the dock at Longfish Bay, secured the mooring lines, and inventoried the tools in the cabin. Long Tian and Yu Jin disembarked and walked along the dirt road out of Longfish Bay, turning towards the stone house at the fork in the road. The roadside weeds swayed in the evening breeze, and the sun-baked soil on the road was slightly warm underfoot, kicking up a thin layer of dust that slowly dissipated in the twilight.