Panama Canal's Locks Stand Test Of Time

The man-made chasm, large enough to swallow the Titanic whole, yawns before him. To reach the bottom takes an elevator, a hard hat and no fear of heights. But for Ivan Lasso, superintendent of the Panama Canal's Pacific locks, entering the void is all in a day's work. The huge 85-year-old lock chambers need a routine overhaul. When the locks were hand-poured in 1913, they were the largest reinforced concrete structures ever, allowing engineers to dream up skyscrapers they would later build in Manhattan. Tall as a six-story building, the 700-ton riveted steel Miter gates - 88 in all in the 50-mile (82 km) canal's three flights of locks - established Pittsburgh as a steel town. The vast "mechanical computer" that controls the outflow of water from the locks - through sluices large enough to accommodate a freight train - put General Electric, then a fledgling company, on the corporate map. Although they are made of massive components, the locks are a simple but delicate machine, ingeniously conceived by long-forgotten engineers. "They were close to being geniuses," Lasso, 38, said with a technician's empathy for their achievement. "What they did at the time would be hard for us to beat today." Now the engineering marvel, under U.S. control since the beginning, is about to be handed over to Panama when the clock strikes noon on Dec. 31. Smart Building After French engineer Ferdinand de Lesseps' failed attempt to build a sea-level canal at Panama in the 1880s, the U.S. constructors who resumed excavation in 1904 decided on a canal with locks. It was the canal's chief engineer, John Stevens, who dreamed up the idea. Army Lt. Col. Harry Hodges and two civilian engineers, Edward Schildhauer and Henry Goldmark, realized his vision, according to "The Path Between the Seas," David McCullough's authoritative 1977 account of the building of the canal. Faced with the obstacle of Panama's cordillera - a steep and geologically unstable 312 ft. (95 m) high dividing range - engineers opted to dam the Chagres River to create an artificial reservoir 85 ft. (26 m) above sea level. Lake Gatun, as it was called, became the headwater of the canal - supplying it with the fresh water vital to its operation - and made up more than half the waterway's course. "The simple concept of creating a large elevated lake and raising and lowering ships by gravity-feeding water through locks is extremely ingenious," Lasso said. Last year, harnessing gravity allowed more than 13,000 ships to be hauled over the central ranges, generating $568 million in revenues for the canal's administrators. Dating from a time when engineers grappled with basic physical principles, the Miraflores Locks showcase simple solutions to imposing mechanical problems. While the giant steel lock gates - more than twice the weight of any before constructed - put a crushing downward force on the hinge bearings, engineers' sleight-of-hand made them weightless. "Our Miter gates are of double-skin design, which allows us to seal and float them like a barge," Lasso says, adding that their design enables them to be towed for routine maintenance at the canal's industrial division workshops. Museum Piece Genius "To me, this is genius," Lasso says, indicating the 70 ft. (21-m) Italian marble table that runs the length of Miraflores Locks control room. The control table, an interactive scale model of the lock chambers outside, opens and closes the Miter gates and controls the subterranean system of sluices that fill and drain the locks. Calibrated brass gauges mark the ebb and flow of waters in the lock chambers outside to the nearest half inch. The lock chambers are picked out in blue marble and mark the passage of ships through the locks outside. Aluminum paddles, like the flippers of a pinball machine, sweep inexorably together as the Miter gates outside draw closed behind a freighter. "The handles activate motors, which operate the machinery outside," Lasso said. A unique design feature prevents operators from making errors in the complex transit procedure. The control table's "interlock system" - a vast mechanical computer made of thousands of interconnecting copper rods and levers - makes it physically impossible to carry out locking procedures out of sequence. Designed so that guiding a ship through the sluices could be carried out by just one operator, the Jules Verne-era technology is still in use as the canal approaches the turn of the century. "We've made some changes, but basically this is original," Lasso said. "It deserves to be in a museum." - (Tim Gaynor, Reuters)