History of The Panama Canal - The Third Locks Scheme (1939)

The Third Locks Scheme (1939)

As the situation in Europe deteriorated in the late-1930s, the USA began to be concerned once more about its ability to move warships between the oceans. The largest U.S. battleships were already so large as to have problems with the canal locks; and there were concerns about the locks being put out of action by enemy bombing.

These concerns led the U.S. Congress to pass a resolution authorising a study into improving the canal's defenses against attack, and into expanding the capacity of the canal to handle large vessels. This resolution was passed on May 1, 1936, and a Special Engineering Section was created by the on July 1, 1937, to carry out the study.

A report was made to Congress on February 24, 1939, recommending that work be carried out to protect the existing lock structures, and to construct a new set of locks capable of carrying larger vessels than the existing locks could accommodate. On August 11, 1939, Congress authorised work to begin.

The plan was to build three new locks, at Gatún, Pedro Miguel, and Miraflores, in parallel with the existing locks, and served by new approach channels. The new locks would add a single traffic lane to the canal, with each chamber being 1,200 ft (365.76 m) long, 140 ft (42.67 m) wide, and 45 ft (13.72 m) deep. The new locks would be 1⁄₂ mi (805 m) to the east of the existing Gatún locks, and 1⁄₄ mi (402 m) to the west of the existing Pedro Miguel and Miraflores locks.

The first excavations for the new approach channels at Miraflores began on July 1, 1940, following the passage by Congress of the Appropriation Act on June 24, 1940. The first dry excavation at Gatún began on February 19, 1941. A considerable amount of material was excavated before the project was finally abandoned; the new approach channels can still be seen in parallel to the original channels at Gatún and Miraflores.

In 2006 the ACP proposed a new plan to create a third lane of locks, using partly the abandoned approach canals from 1940's. After a confirming referendum, the works have started in 2007.