Aug 23, 2011
7 Wonders of the Industrial World - Part VI
The Panama Canal was one of the largest and most difficult engineering projects ever undertaken. It is a 48 mile (77 km) international waterway that allows ships to pass between the Atlantic and Pacific Oceans, saving about 8000 miles from the journey around Cape Horn on the southern tip of South America. From the Atlantic side, the trip first takes you through a 7 mile (11 km) dredged channel in Limón Bay, then proceeds 11.5 miles (18.5 km) to the Gatun Locks. This is a series of three locks that raises ships 85 feet (26 metres) to Gatun Lake. The route continues south for 32 miles (51.5 km) to the Culebra Cut, which is a channel 8 miles (13 km) long and 492 feet (150 metres) wide. At the end of this are the Pedro Miguel Locks which lower ships 31 feet (9.4 metres) to a lake which takes you to the Miraflores Locks which lower ships an additional 52.5 feet (16 metres) to sea level in the bay of Panama in the Pacific Ocean.
The earliest suggestion for a canal across the Isthmus of Panama was made in 1534. After realizing the riches of Peru, Ecuador, and Asia, and taking into consideration the amount of time it took the gold to reach the ports of Spain, Charles V, Holy Roman Emperor and King of Spain ordered a survey for a route through Panama that would make the trips shorter. A working plan was drawn up in 1529, but never used.
Several surveys were made between 1850 and 1875 and showed that only two routes were practical, one across Panama and another across Nicaragua. In 1876 an international company was organized and two years later it obtained a concession from the Colombian government to dig a canal across the isthmus. The international company failed, and in 1880 a French company was organized by Ferdinand Marie de Lesseps, the builder of the Suez Canal.
The contract for the canal’s construction was signed on March 12th, 1881, and it was agreed the work would be carried out for 512 million French francs. De Lesseps opted for a sea-level canal based on the construction of the Suez Canal. He believed that if a sea-level canal worked when constructing the Suez Canal, it must work for the Panama Canal.
During 1882 the excavation of the Culebra Cut was started. As work proceeded, the worry of landslides and what slope should be adopted to avoid them became a major concern. In 1883 it was realised there was a tidal range of 20 feet at the Pacific, whereas, the Atlantic range was only about 1 foot. It was concluded that this difference in levels would be a danger to navigation. It was proposed that a tidal lock should be constructed at Panama to preserve the level from there to Colon. This plan would save about 10 million cubic metres of excavation.
Eventually, in 1899 the French attempt at constructing the Panama Canal was seen to be a failure. However, they had excavated a total of 59.75 million cubic metres which included 14.255 million cubic metres from the Culebra Cut. This lowered the peak by 102 metres. The value of work completed by the French was about $ 25 million. When the French left, they left behind a considerable amount of machinery, housing, and a hospital.
In 1899 the US Congress created an Isthmian Canal Commission to examine the possibilities of a Central American canal and to recommend a route. In June 1902, the U.S. Senate voted in favour of pursuing the Panamanian option, provided the necessary rights could be obtained.
The United States, under President Theodore Roosevelt, bought out the French equipment and excavations for $40 million. The first American steam shovel started work on the Culebra Cut on 11th November 1904. By December 1905 there were 2,600 men at work in the Culebra Cut.
John Frank Stevens, Chief Engineer from 1905 to 1907, successfully argued the case against the incredibly massive excavation required for a sea-level canal like the French had tried to build and convinced Theodore Roosevelt of the necessity and feasibility of a canal built with dams and locks.
Constructing the Panama Canal with locks still required the excavation of an enormous volume of material and was envisioned by Stevens as a massive earth-moving project using the Panama Railway as efficiently as possible. The railroad, starting in 1904, had to be comprehensively upgraded with heavy-duty double-tracked rails over most of the line to accommodate all the new rolling stock of about 115 heavy-duty locomotives and 2,300 dirt spoils railroad cars.
Peak excavation within the Culebra Cut exceeded 512,500 cubic metres of material in the first three months of 1907 and the total workforce exceeded 39,000. More than 4,000 wagons were used for the removal of the excavated material. Each wagon was capable of carrying 15 cubic metres of material. These wagons were hauled by 160 locomotives and unloaded by 30 Lidgerwood unloaders.
In 1907 there was a major slide at Cucaracha. The initial crack was first noted on October 4th, 1907, then without warning approximately 382,000 cubic metres of clay, moved more than 4 metres in 24 hours. The Cucaracha slide was to become a problem again in 1913, when it crossed the cut until it reached the opposite bank. The steam shovels excavated the slide as it was moving and eventually won the battle.
The building of the canal was completed in 1914, two years ahead of the target date of June 1, 1916. The canal was formally opened on August 15, 1914 with the passage of the cargo ship SS Ancon. Coincidentally, this was also the same month that fighting in World War I began in Europe.
Almost a hundred years since its opening, the canal continues to enjoy great success. Even though the ships for which the canal was built are long gone, the canal is still one of the most highly travelled waterways in the world, handling over 12,000 ships per year. The 51-mile crossing takes about nine hours to complete, an immense time saving when compared with rounding the tip of South America.