On the upstream face of the Diverter. There, the black water of the Inland Sea met the giant stone granite wall, the intake works of Sluice Twelve presented a scene of terrifying high-pressure violence.
The intake tower was a massive horseshoe of dressed cut stone stonework projecting thirty yards into the pool. Beneath the surface, three arched intake ports, each fifteen feet wide and thirty feet high, sucked hundreds of thousands of gallons of water per minute down into the underground water chute that fed Sluice Twelve’s outward gate.
To balance the sixty-ton dead weight of that outward gate, the original royal designers had installed two four-ton cast-iron balance weights inside upright stone wells built directly into the pier stonework. Each balance weight was a solid metal tube of pig-iron four feet in width and six feet long, suspended from four-inch wrought-iron link chains that passed over huge overhead sprockets on the crest narrow high walkway.
Tomas stood on the mooring deck of the Diverter’s salvage barge. A heavy sixty-foot scow built of six-inch pitch-pine timbers, snubbed tight against the upstream coping stones of Pier Twelve by six steel mooring cables.
Beside him, old Renn Tal was peering down into the churning intake well through a brass sighting tube fitted with a sealed glass lens. An animal fat lamp mounted inside the tube cast a sickly yellow cone of light down through eight feet of roiling, foam-streaked water.
