Gatun Locks
   HOME

TheInfoList



OR:

The Panama Canal locks () are a
lock Lock(s) or Locked may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainme ...
system that lifts ships up to the main elevation of the
Panama Canal The Panama Canal () is an artificial waterway in Panama that connects the Caribbean Sea with the Pacific Ocean. It cuts across the narrowest point of the Isthmus of Panama, and is a Channel (geography), conduit for maritime trade between th ...
and lowers them down again. The original canal had a total of six steps (three up, three down) for a ship's passage. The total length of the lock structures, including the approach walls, is over . The locks were one of the greatest
engineering Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, s ...
works ever to be undertaken when they opened in 1914. No other concrete construction of comparable size was undertaken until the
Hoover Dam The Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado, Black Canyon of the Colorado River (U.S.), Colorado River, on the border between the U.S. states of Nevada and Arizona. Constructed between 1931 and 1936, d ...
, in the 1930s. There are two independent transit lanes, since each lock is built double. The size of the original locks limits the maximum size of ships that can transit the canal; this size is known as
Panamax Panamax and New Panamax (or Neopanamax) are terms for the size limits for ships traveling through the Panama Canal. The limits and requirements are published by the Panama Canal Authority (ACP) in a publication titled "Vessel Requirements". ...
. Construction on the
Panama Canal expansion project The Panama Canal expansion project (), also called the Third Set of Locks Project, doubled the capacity of the Panama Canal by adding a new traffic lane, enabling more ships to transit the waterway, and increasing the width and depth of the lane ...
, which included a third set of locks, began in September 2007, finished by May 2016 and began commercial operation on June 26, 2016. The new locks allow transit of larger, New Panamax ships, which have a greater cargo capacity than the previous locks were capable of handling.


Design

There are twelve locks (six pairs) in total. A two-step flight at Miraflores and a single pair at Pedro Miguel lift ships from the
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...
up to
Gatun Lake Gatun Lake () is a mostly freshwater (slightly saline near the locks) reservoir to the south of Colón, Panama. At approximately above sea level, it forms a major part of the Panama Canal, carrying ships of their transit across the Isthmus of P ...
; then a triple flight at Gatun lowers them to the
Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...
side. All three sets of locks are paired; that is, there are two parallel flights of locks at each of the three lock sites. This, in principle, allows ships to pass in opposite directions simultaneously; however, large ships cannot cross safely at speed in the Culebra Cut, so in practice ships pass in one direction for a time, then in the other, using both "lanes" of the locks in one direction at a time. In this usage pattern, the paired locks offer redundancy during maintenance or in the event of mechanical issues. The lock chambers are wide by long, with a usable length of . These dimensions determine the maximum size of ships that can use the canal; this size is known as Panamax. The total lift (the amount by which a ship is raised or lowered) in the three steps of the Gatun locks is ; the lift of the two-step Miraflores locks is . The single-step Pedro Miguel locks have a lift of . The lift at Miraflores actually varies due to the extreme tides on the Pacific side, between at extreme high tide and at extreme low tide; tidal differences on the Atlantic side are very small. The lock chambers are massive concrete structures. The side walls are from thick at the bases; toward the top, where less strength is required, they taper down in steps to . The center wall between the chambers is thick and houses three galleries that run its full length. The lowest of these is a drainage tunnel; above this is a gallery for electrical cabling; and toward the top is a passageway that allows operators to gain access to the lock machinery.


Filling and draining

Each lock chamber requires of water to fill it from the lowered to the raised position; the same amount of water must be drained from the chamber to lower it again. Embedded in the side and center walls are three large water
culvert A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe (fluid conveyance), pipe, reinforced concrete or other materia ...
s that are used to carry water from the lake into the chambers to raise them, and from each chamber down to the next, or to the sea, to lower them. These culverts start at a diameter of and reduce to in diameter, large enough to accommodate a train. Cross culverts branch off from these main culverts, running under the lock chambers to openings in the floors. There are fourteen cross culverts in each chamber, each with five openings; seven cross culverts from the sidewall main culverts alternate with seven from the center wall culvert. The water is moved by gravity and is controlled by huge valves in the culverts. Each cross culvert is independently controlled. A lock chamber can be filled in as little as ten minutes.


Gates

The gates separating the chambers in each flight of locks must hold back a considerable weight of water, and must be both reliable and strong enough to withstand accidents, as the failure of a gate could unleash a flood of water downstream. These gates range from high, depending on position, and are thick. The tallest gates are at Miraflores, due to the large tidal range there. The heaviest leaves weigh ; the hinges themselves each weigh . Each gate has two leaves, wide, which close to a "V" shape with the point upstream. This arrangement has the effect that the force of water from the higher side pushes the ends of the gates together firmly. The gates can be opened only when, in the operating cycle, the water level on both sides is equal. The original gate machinery consisted of a huge drive wheel, powered by an electric motor, to which was attached a connecting rod, which in turn attached to the middle of the gate. The gates are hollow and buoyant, much like the hull of a ship, and are so well balanced that two motors are enough to move each gate leaf. If one motor fails, the other can still operate the gate at reduced speed. All but one chamber contains a pair of auxiliary gates, which can be used to divide the chamber in two. This design allows for the transit of smaller vessels less than long, such as canal tugs, without using the full quantity of water. The auxiliary gates were originally incorporated because the overwhelming majority of all ships of the early 1900s were less than long and therefore did not need the full length of the lock chamber.


Mules

From the outset, it was considered an important safety feature that ships be guided through the lock chambers by electric locomotives, known as ''mulas'' (''
mule The mule is a domestic equine hybrid between a donkey, and a horse. It is the offspring of a male donkey (a jack) and a female horse (a mare). The horse and the donkey are different species, with different numbers of chromosomes; of the two ...
s'', named after
the animals The Animals, currently billed as Eric Burdon & the Animals (featuring original frontman Eric Burdon) and also as Animals & Friends (featuring original drummer John Steel (drummer), John Steel), are an English Rock music, rock band formed in Ne ...
traditionally used to cross the isthmus of Panama), running on the lock walls. These mules are used for side-to-side and braking control in the locks, which are narrow relative to modern-day ships. Forward motion into and through the locks is actually provided by the ship's engines and not the mules. A ship approaching the locks first pulls up to the guide wall, which is an extension of the center wall of the locks, where it is taken under control by the mules on the wall before proceeding into the lock. As it moves forward, additional lines are taken to mules on the other wall. With large ships, there are two mules on each side at the bow, and two each side at the stern—eight in total, allowing for precise control of the ship. Mules are not used on the new expansion locks. The mules themselves run on paired
broad gauge A broad-gauge railway is a railway with a track gauge (the distance between the rails) broader than the used by standard-gauge railways. Broad gauge of , more known as Russian gauge, is the dominant track gauge in former Soviet Union countries ...
railway tracks. The track closest to the canal is used for towing and has rack tracks for geared operation. The track inland is used to return the mules to their starting point and does not have racks except on the steep inclines between lock chambers. Traction is by electric power, supplied through a
third rail A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a track (r ...
laid below surface level on the land side.The Panama Canal: Conduit power for the Mules
2009
Each mule has a powerful
winch A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension (physics), tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a Bobb ...
; these are used to take cables in or pay them out to keep the ship centered in the lock while moving it from chamber to chamber. File:Mule in the Miraflores Locks.JPG, A mule in action at the Miraflores locks File:08-130 Esclusas de Miraflores (23).jpg, A mule on a
slope In mathematics, the slope or gradient of a Line (mathematics), line is a number that describes the direction (geometry), direction of the line on a plane (geometry), plane. Often denoted by the letter ''m'', slope is calculated as the ratio of t ...
. The rack is inside the running rail at the left of the track, and the
third rail A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a track (r ...
is on the right of the track.


Safety features

A failure of the lock gates—for example, caused by a runaway ship hitting a gate—could unleash a flood on the lands downstream of the locks, as the lake above the locks (
Gatun Lake Gatun Lake () is a mostly freshwater (slightly saline near the locks) reservoir to the south of Colón, Panama. At approximately above sea level, it forms a major part of the Panama Canal, carrying ships of their transit across the Isthmus of P ...
or Miraflores Lake) drains through the lock system. Extra precaution against this is provided by doubling the gates at both ends of the upper chamber in each flight of locks; hence, there are always at least two gates in each flight of locks that would have to fail to allow the higher level of water to pass downstream. The additional gates are away from the operating gates. Originally the locks also featured chain barriers, which were stretched across the lock chambers to prevent a ship from running out of control and ramming a gate, and which were lowered into the lock floor to allow the ship to pass. These ''fender chains'' featured elaborate braking mechanisms to allow a ship of up to 10,000 tons to be safely stopped. However, given the precise control of ships made possible by the mules, it was very unlikely that these chains would ever be required. With many modern canal users weighing over 60,000 tons, and given the expense of maintaining them, the fender chains were reduced in number in 1976 and finally removed in 1980. Beyond this, the original design of the locks had yet another safety feature, emergency
dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...
s that could be swung across the locks at the upper end of every flight. These consisted of swinging bridges, from which
girder A girder () is a Beam (structure), beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing ''flanges'' separated by a sta ...
s were lowered to the lock floor; steel shutters could then be run down these girders to block the flow of water. Never used, they were removed in the 1950s.In the late 1930s, the original emergency dams were replaced by new dams, which were raised out of slots in the bottom of the lock chambers, either hydraulically or by compressed air. The new dams were retired in the late 1980s, and today, no emergency dams are in place.


Controls

Since all the lock equipment is operated electrically, the process of locking a ship up or down can be controlled from a central control room, which is located on the center wall of the upper flight of locks. The controls were designed from the outset to minimize the chance of operator error and include a complete model of the locks, with moving components that mirror the state of the real lock gates and valves. In this way, the operator can see exactly what state the locks and water valves are in. Mechanical interlocks are built into the controls to make sure that no component can be moved while another is in an incorrect state—for example, opening the drain and filling the valves of a lock chamber simultaneously.


Construction

The construction of the locks began with the first concrete laid at Gatun, on August 24, 1909, by the Philadelphia-based company Day & Zimmermann (formerly known as Dodge & Day). The Gatun locks are built into a cut made in a hill bordering the lake, which required the excavation of of material, mostly rock. The locks themselves were made of of concrete. The quantity of material needed to construct the locks required extensive measures to be put in place to handle the stone and cement. Stone was brought from Portobelo to the Gatun locks, while the work on the Pacific side used stone quarried from Ancon Hill. Huge overhead cableways were constructed to transport concrete into the construction at Gatun. high towers were built on the banks of the canal, and cables of steel wire were strung between them to span the locks. Buckets running on these cables carried up to six tons of concrete at a time into the locks. Electric railways were constructed to take stone, sand, and cement from the docks to the concrete mixing machines, from where another electric railway carried two 6-ton buckets at a time to the cableways. The smaller constructions at Pedro Miguel and Miraflores used cranes and steam locomotives in a similar manner. The Pacific-side locks were finished first—the single flight at Pedro Miguel in 1911 and Miraflores in May 1913. The seagoing tug ''Gatun'', an Atlantic entrance working tug used for hauling barges, made the first trial lockage of Gatun Locks on September 26, 1913. The lockage went perfectly, although all valves were controlled manually since the central control board was not yet ready.


Map


References


External links


''A History of the Panama Canal''
from the Panama Canal Authority {{Coord missing, Panama Locks
Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
Articles containing video clips Locks (water navigation)