Enlarging the Panama Canal
by Alden P. Armagnac

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Steam shovels will soon be clanking again at the Panama Canal.  Only a little more than a quarter century after the opening of this "life line" of the U.S. Navy and crossroads of the world's maritime commerce, workers will break ground for a monster third set of locks—a project whose $277,000,000 cost equals more than half that of the present canal!

The giant engineering scheme calls for conversion of the present "two-lane" canal across the Isthmus into a "three-lane" canal.  To do this, three sets of oversize single-chamber locks will be built, parallel to the present twin-chamber locks but at some distance from them.  there will be no need to dig a whole new canal, since the "Big Ditch" itself will easily carry the traffic.

Why the new locks?  First and foremost, they will assure the U.S. Fleet of unobstructed passage between the oceans, in cases of emergency.  Canal authorities long have been jittery over the possibility of sabotage or direct attack on the present locks.  A vessel might be blown up, or time bombs might be dropped, in a lock chamber; or the locks might be bombed by raiding planes.   If a heavy explosion or a lucky hit from the air happened to destroy two side-by-side lock chambers at once, the entire Canal would be put of out commission.   Therefore, for many months, a force of several thousand men has been working night and day to equip the old locks with "special protective devices" of a secret nature.  But the Navy will feel still more comfortable when the new locks are built, from a quarter mile to a half mile away from the old ones, so that both cannot be attacked simultaneously.  Every known safeguard against bombing and sabotage will be built into them, from the foundation up.

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Making The Canal Fit Modern Ships:  The drawing above illustrates how the design of our warships has been restricted by the size of the present Panama locks, and how the larger locks will permit the building of bigger and more powerful naval vessels.  Three liners, the "Normandie," "Queen Mary" and "Queen Elizabeth" are too big for present locks.

Secondly, the enormous size of the new locks, 1,200 feet long and 135 feet wide, will comfortably accommodate the biggest men-of-war and ocean liners afloat or contemplated.  Widened by recent addition of antitorpedo bulges, some of our modernized battleships can barely scrape through the old locks, with only a foot to spare on each side!  Our giant aircraft carriers Lexington and Saratoga make almost as tight a fit.  Until now, the 110-foot width of the existing locks has limited the dimensions of all U.S. warships, including the 35,000-ton and 45,000-ton battleships now under construction.  As for the big merchant vessels, the Queen Elizabeth, the Queen Mary, and the Normandie, they could not squeeze into the old locks at all.  The projected locks will have plenty of room for all comers.

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Thirdly, the sheer volume of peacetime traffic through the Panama Canal, steadily rising through the years, will eventually call for more locks to handle it.  From this standpoint alone, the Governor of the Panama Canal recently declared, the third-lock project should be started within nine to eleven years.   Present plans simply advance the date for completion of an outstanding national asset, both in war and in peace.

Connecting with the present waterway several miles above and below the existing locks, "by-pass" or approach channels will lead to the new locks, so that canal traffic may be shunted through either set.   Criss crossing routes will enable a ship to be detoured around locks that may be out of commission.

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On left, the present two-lane Gatun Locks.  The new locks, connected to the canal through "by-pass" channels, will be a half mile away.  Right, a freighter plows through Gaillard Cut.

Starting from the Pacific, for example, a vessel may pass through either the old or new Miraflores Locks, which raise it in two lifts to Miraflores Lake.  the old and new single-flight Pedro Miguel Locks then offer alternate gateways into Gaillard Cut, the artificial arm of Gatun Lake formerly known as Culebra Cut.  Separate channels from broad Gatun Lake allow the ship to be routed through either the old or new three-flight Gatun Locks for its descent to the Atlantic.

Favorable sites for the new locks and their channels were found by a preliminary survey in the field.  With core drills, engineers brought up samples of subsurface rock, to make sure of a substantial foundation for the massive concrete lock chambers.  Artificial earthquakes, produced by setting off explosives, proved the rock formations free of faults.  Investigations showed that the present water supply would amply suffice for both the old and new lock systems.

Actual work on the third-lock system will begin at once, with initial funds of $114,000,000 just voted by Congress.  As the huge project gets under way, whole new towns will spring up at construction centers.   First steps include building roads, relocating railways, and excavating the locks sites and approach channels, which total about ten miles in length.  Then will come the building of the giant locks themselves.  Fast-moving world events may call for drastic speed-up measures to hasten the mighty engineering feat.

From:  Popular Science (September 1940, Vol 137, No 3)

June 27, 2001