Panama Canal - Transit Procedures
The Panama Canal, 80.5 km long and connecting the Atlantic and Pacific Oceans, extends northwest to southeast. Three sets of locks raise and lower vessels 26 m above sea level over the Continental Divide. The Atlantic entrance is 53.9 km north and 43.5 km west of the Pacific entrance.
There are many different parts of the Panama Canal that all work together. There are three locks in the Panama Canal, Gatun, Pedro Miguel, and Miraflores. A ship entering the Canal from the Atlantic Ocean to the Pacific Ocean enters at Gatun Locks and exits at Miraflores Locks. While going through the Panama Canal, the ship will be raised and lowered eighty-five feet. After going through Gatun Lake and Gaillard Cut, the ship enters Pedro Miguel Locks and is lowered 31 feet. After Pedro Miguel Locks, one mile later it enters Miraflores Locks to be lowered the remaining 54 feet to the Pacific Ocean. The locks are 110 feet wide, 1,000 feet long, and seven stories high. Each time a ship goes through (a lockage), 52 million gallons of water are used. There are three lock chambers in every lock station. It usually takes a whole day (8 or 10 hours) to transit the canal from one ocean to the other.
A ship from the Atlantic Ocean enters the Panama Canal waters of Limon Bay from the breakwater at Cristobal. Upon arrival in Panama Canal waters, if a vessel is not scheduled to transit that day, it will drop anchor and wait for its scheduled transit time. Otherwise, the vessel will sail toward the first lock. The Panama pilots take control of the vessel during its transit through Panama Canal waters. The chief pilot will instruct the ship's captain as to the speed and direction of the vessel. The chief pilot also will tell the tug operators, line-handlers, and locomotive engineers what assistance they need to provide, while the pilot remains in contact with the Panama Canal TCC and each lock tower. The captain relays the pilot's instructions to his crew members, who perform the proper maneuver.
As the vessel approaches the first set of locks, another launch boat delivers linehandlers to the ship. The line-handlers board the vessel and prepare to receive the cables, attached to each locomotive, that pull the vessel through each lock chamber. A Panamax vessel requires 20 line-handlers, 12 locomotives (six at the bow and six at the stern, three to port and three to starboard), and one tug pushing from the stern to assist the vessel through each lock. One pilot will remain on the bridge at all times, moving between the wheel room and to either wing bridge to call out instructions, "full ahead," "rudder 10 degrees," "ahead one-third," "midships," etc. The other pilot will move about the vessel from bow to stern, port to starboard, keeping watch on the ship's progress throughout the canal transit.
The vessel steams 10.4 km under tug assist to the Gatun Locks, the first set of locks. Three "steps" at Gatun Locks, individual chambers into which ships are maneuvered, raise the vessel 26 m to Gatun Lake. Each chamber is 34 m wide and 305 m long. This first set of locks is about 2 km long.
At the first lock,Gatun Lock, the chief pilot will have the captain's crew maneuver the vessel to the approach wall, where the line-handlers attach the cables of the locomotives to the vessel. The pilot continues calling out maneuvers to the captain, and the vessel continues forward with assistance from the tug at the stern. When the vessel reaches the first chamber of the lock, linehandlers will attach the cables of the remaining locomotives to the vessel and draw them tight to stabilize the vessel for entry into the chamber.
Together with the locomotives and tugs and under its own power, the vessel moves into the first chamber, where miter gates close behind the vessel's stern to lock it into the chamber. Water from the second chamber flows into the first chamber and lifts the vessel to the water level of the second chamber. Once the vessel has stopped rising, the miter gates at the vessel's bow open, and the vessel moves forward into the second chamber with assistance from the locomotives and under its own power. The process repeats for the second chamber. In the last chamber, the vessel is lifted to the level of Gatun Lake. In each chamber lockage, raising a vessel requires about 15 minutes, and each lock transit will last from 45 minutes to more than an hour. Transit time, however, will vary with daily vessel traffic. Once the miter gates of the last chamber open and the vessel has cleared the gates, the cables from each locomotive are released, and the vessel steams through the tropical waters of Gatun Lake under its own power 37.8 km from the Gatun locks to the Gaillard Cut. The water in Gatun Lake pushes ships through the lock chambers, using 201 million liters of water for each ship transit.
The Gaillard Cut traverses 12.6 km through the Continental Divide of Panama at the highest point of the isthmus. Before construction of the canal, the cut was more than 123 m above sea level and 91 m wide. One portion was widened to 152 m during the 1930's and 1940's, and the remaining portions were completed by 1971. Starting in the 1990s the cut was widened to 192 m in the straight sections and 223 m at the curves to allow double passage of Panamax vessels. Panamax ships were limited to single passage through the canal until the widening project was complete. The PCC conducted tests in May 1999 to determine the safety of a double passage of Panamax vessels and measure vessel performance. In June 1999, double passage of Panamax vessels began. The widening of the cut was finished by 2002 and increased transit capacity by about 20 percent.
Once past the Gaillard Cut, the vessels encounter the first of two locks that will lower the vessel to the level of the Pacific Ocean. The first lock, Pedro Miguel, has one chamber, 11/3 km long, which will lower the vessel 9 m. From Pedro Miguel, the vessel sails into Lake Miraflores and proceeds about 2 km to the Miraflores Locks, whose two chambers lower the vessel to sea level. From the Miraflores Locks, the vessel moves toward the Pacific Ocean under the Bridge of the Americas, where the pilot returns the vessel to the captain and boards the launch boat.
A complete transit takes 9-12 hours after entering the first set of locks, although a vessel may anchor in the canal waters, waiting to transit the canal, from a few hours to a few days.
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