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{{Multiple image|direction=vertical|align=right|image1=Panama Canal Map EN.png|image2=Panama Canal Gatun Locks.jpg|width=220|caption1=Sequence of locks and passages that a vessel passes through while transiting the [[Panama canal]]|caption2=The Gatun Locks, looking north towards the [[Atlantic Ocean]]}} |
{{Multiple image|direction=vertical|align=right|image1=Panama Canal Map EN.png|image2=Panama Canal Gatun Locks.jpg|width=220|caption1=Sequence of locks and passages that a vessel passes through while transiting the [[Panama canal]]|caption2=The Gatun Locks, looking north towards the [[Atlantic Ocean]]}} |
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The '''Panama Canal locks''' ({{lang-es|Esclusas del Canal de Panamá}}) are a [[canal lock|lock]] system that lifts ships up {{convert|85|ft|m|abbr=off|sigfig=2}} to the main elevation of the [[Panama Canal]] and down again. |
The '''Panama Canal locks''' ({{lang-es|Esclusas del Canal de Panamá}}) are a [[canal lock|lock]] system that lifts ships up {{convert|85|ft|m|abbr=off|sigfig=2}} to the main elevation of the [[Panama Canal]] and down again. |
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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]]. Construction on the [[Panama Canal expansion project]], which included a third set of locks, |
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]]. Construction on the [[Panama Canal expansion project]], which included a third set of locks, lasted from September 2007 to May 2016.<ref>{{cite web|url=https://www.pancanal.com/eng/expansion/rpts/informes-de-avance/expansion-report-201210.pdf|title=Panama Canal Expansion Project report - October 2012|publisher=Panama Canal Authority|url-status=dead|archive-url=https://web.archive.org/web/20130310193919/http://www.pancanal.com/eng/expansion/rpts/informes-de-avance/expansion-report-201210.pdf|archive-date=2013-03-10}}{{in lang|en}}</ref> It opened for commercial operation on 26 June 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.<ref name=NYT062016>{{cite news|url=https://www.nytimes.com/aponline/2016/06/26/world/americas/ap-lt-panama-canal-expansion.html|title=Panama Canal Opens $5B Locks, Bullish Despite Shipping Woes|publisher=[[Associated Press]]|work=[[The New York Times]]|url-status=live|language=en-US|date=2016-06-26|access-date=2016-06-26|archivedate=June 26, 2016|archiveurl=https://web.archive.org/web/20160626045957/https://www.nytimes.com/aponline/2016/06/26/world/americas/ap-lt-panama-canal-expansion.html}}</ref> |
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== Design == |
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There are twelve locks in total. A two-step flight at [[Miraflores (Panama)|Miraflores]], and a single flight at Pedro Miguel, lift ships from the [[Pacific]] up to [[Gatun Lake]]; then a triple flight at Gatun lowers them to the [[Atlantic]] 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.{{fact|date=March 2022}} |
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[[File:Miraflores Locks Panama Canal 24h time lapse - small.webm|thumb|left|24-hour time-lapse of the upper chamber of the Miraflores Locks]] |
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The lock chambers are {{convert|110|ft|m|abbr=on|sigfig=4}} wide by {{convert|1050|ft|m|abbr=on|sigfig=3}} long, with a usable length of {{convert|1000|ft|m|abbr=on|sigfig=3}}. 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 {{convert|85|ft|m|abbr=on|sigfig=3}}; the lift of the two-step Miraflores locks is {{convert|54|ft|m|abbr=on|sigfig=2}}. The single-step Pedro Miguel locks have a lift of {{convert|31|ft|m|abbr=on|sigfig=2}}. The lift at Miraflores actually varies due to the extreme tides on the Pacific side, between {{convert|43|ft|m|abbr=on|sigfig=2}} at extreme high tide and {{convert|64.5|ft|m|abbr=on|sigfig=2}} at extreme low tide; tidal differences on the Atlantic side are very small.{{fact|date=March 2022}} |
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The lock chambers are massive concrete structures. The side walls are from {{convert|45|to|55|ft|m|abbr=on|sigfig=2}} thick at the bases; toward the top, where less strength is required, they taper down in steps to {{convert|8|ft|m|abbr=on|sigfig=2}}. The center wall between the chambers is {{convert|60|ft|m|abbr=on|sigfig=2}} 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. |
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== Filling and draining == |
== Filling and draining == |
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Each lock chamber requires {{convert|26,700,000|usgal|m3|abbr=on|sigfig=3}} 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.<ref>[http://www.pancanal.com/eng/noticiero/canal-faqs/index.html Panama Canal Authority FAQ]</ref> |
Each lock chamber requires {{convert|26,700,000|usgal|m3|abbr=on|sigfig=3}} 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.<ref>[http://www.pancanal.com/eng/noticiero/canal-faqs/index.html Panama Canal Authority FAQ]</ref> |
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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 eight minutes. There is significant turbulence in the lock chamber during this process {{Citation needed|reason=I went through the locks and there was only very minimal "turbulence" if at all on the surface of the water|date=December 2017}}. |
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== Gates == |
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[[File:Panama Canal Gatun Locks opening.jpg|thumb|Gates of the Gatun locks open for a cruise ship making its way down to the [[Caribbean]] end of the canal. The gates at both ends of the upper chamber are doubled for safety.]] |
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[[File:Esclusas de Miraflores. Panamá.jpg|thumb|Miraflores locks]] |
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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 catastrophic flood of water downstream.{{fact|date=March 2022}} |
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These gates are enormous, ranging from {{convert|47|to|82|ft|m|2|abbr=on|sigfig=3}} high, depending on position, and are {{convert|7|ft|m|2|abbr=on|sigfig=2}} thick. The tallest gates are at [[Miraflores (Panama)|Miraflores]], due to the large tidal range there. The heaviest leaves weigh {{convert|662|t|ST LT|abbr=on|sigfig=3}}; the hinges themselves each weigh {{convert|16.7|t|lb|0|abbr=on|sigfig=3}}. Each gate has two leaves, {{convert|65|ft|m|2|abbr=on|sigfig=3}} 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.{{fact|date=March 2022}} |
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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. These mechanisms were replaced with hydraulic [[strut]]s beginning in January 1998, after 84 years of service. The gates are hollow and buoyant, much like the hull of a ship, and are so well balanced that two {{convert|19|kW|hp|0|abbr=on}} motors are enough to move each gate leaf. If one motor fails, the other can still operate the gate at reduced speed.{{fact|date=March 2022}} |
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Each chamber also 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, 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 {{convert|600|ft|m|0|abbr=on|sigfig=3}} long and therefore did not need the full length of the lock chamber. These gates are now rarely used; instead, small boats such as tour boats, tugs, and yachts are passed in groups.{{fact|date=March 2022}} |
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== Mules == |
== Mules == |
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The canal's mules run on [[Rack railway|rack tracks]] with broad gauge, {{Track gauge|5ft|disp=1}},<ref>{{cite web|url=http://www.panamarailroad.org/loco.html|title=The Panama Canal Locomotives|access-date=2012-12-11|publisher=panamarailroad}}</ref> |
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[[File:Mule in the Miraflores Locks.JPG|thumb|left|A mule in action at the Miraflores locks]] |
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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]]s'', named after the animals 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 centre 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.{{fact|date=March 2022}} |
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The mules themselves run on [[Rack railway|rack tracks]] with broad gauge, {{Track gauge|5ft|disp=1}},<ref>{{cite web|url=http://www.panamarailroad.org/loco.html|title=The Panama Canal Locomotives|access-date=2012-12-11|publisher=panamarailroad}}</ref> to which they are [[gear]]ed. Traction is by electric power, supplied through a third rail laid below surface level on the land side. Each mule has a powerful [[winch]], operated by the driver; these are used to take two cables in or pay them out to keep the ship centered in the lock while moving it from chamber to chamber. With as little as {{convert|2|ft|cm|abbr=on|sigfig=1}} of clearance on each side of a ship, considerable skill is required on the part of the operators. |
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Smaller vessels, such as small tour boats and private yachts, are taken as ''handline'' transits, where mooring lines to the lock walls are handled manually by line handlers on the ship.{{fact|date=March 2022}} |
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==Safety features== |
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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]] or [[Miraflores (Panama)|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 {{convert|70|ft|m|abbr=on|sigfig=2}} away from the operating gates. |
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[[File:Fender chains of the Miraflores locks, Panama Canal - 19380308.jpg|thumb|Fender chain (circa 1938)]] |
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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.{{fact|date=March 2022}} |
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Beyond this, the original design of the locks had yet another safety feature, emergency [[dam]]s that could be swung across the locks at the upper end of every flight. These consisted of swinging bridges, from which [[girder]]s were lowered to the lock floor; steel shutters could then be run down these girders to block the flow of water. Monthly drills were held, by night and day, to make sure that these dams could be deployed in an emergency.{{fact|date=March 2022}} |
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In the late 1930s, the original 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.{{fact|date=March 2022}} |
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==Controls== |
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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 centre wall of the upper flight of locks. The controls were designed from the outset to minimise 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.{{fact|date=March 2022}} |
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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.{{fact|date=March 2022}} |
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== Construction == |
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[[File:Gatun Locks, Panama Canal LCCN2007664073.tif|thumb|700px|Gatun Locks under construction, circa 1913]] |
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[[File:Panama Canal Locks Construct.jpeg|thumb|The middle wall of Gatun locks, during construction, in 1910. The man standing below and right of the culvert illustrates the scale.]] |
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[[File:Panama Canal Lock Forms.jpeg|thumb|The main culvert forms are seen in the foreground here during construction; behind can be seen the towering wall forms.]] |
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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).{{fact|date=March 2022}} |
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The Gatun locks are built into a cut made in a hill bordering the lake, which required the excavation of {{convert|5000000|cuyd|m3|abbr=off|sigfig=2}} of material, mostly rock. The locks themselves were made of {{convert|2046100|cuyd|m3|abbr=on|sigfig=4}} of concrete.{{fact|date=March 2022}} |
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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.{{fact|date=March 2022}} |
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Huge overhead cableways were constructed to transport concrete into the construction at Gatun. {{convert|85|ft|m|abbr=on|sigfig=2}} high towers were built on the banks of the canal, and cables of {{convert|2.5|in|cm|abbr=on|sigfig=1}} 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 (Panama)|Miraflores]] used cranes and steam locomotives in a similar manner.{{fact|date=March 2022}} |
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Concrete is normally moulded in [[formwork]], temporary structures that give shape to the concrete as it sets. For a simple construction, these would normally be made of wood, but the scale of the locks demanded extraordinary forms.{{fact|date=March 2022}} |
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The forms for the walls consisted of towers, fronted with braced vertical sheets, {{convert|7.5|in|cm|abbr=on|sigfig=2}} thick, mounted on rails to allow the locks to be constructed in sections. A section of lock would be poured behind the form, and when it was set, the form would be moved to do the next section. Each of the twelve towers was {{convert|78|ft|m|abbr=on|sigfig=2}} high by {{convert|36|ft|m|abbr=on|sigfig=2}} wide. The forms for the culverts were made of steel and were collapsible so they could be removed and moved along after each section of culvert had set. In all, there were 33 forms for the centre and side-wall culverts, each {{convert|12|ft|m|abbr=on|sigfig=2}} long, and 100 smaller forms for the lateral culverts.{{fact|date=March 2022}} |
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The Pacific-side locks were finished first—the single flight at Pedro Miguel in 1911 and [[Miraflores (Panama)|Miraflores]] in May 1913.{{fact|date=March 2022}} |
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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.{{fact|date=March 2022}} |
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{{Clear}} |
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==Map== |
==Map== |
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[[File:Gatun Locks 03 2014 Panama Canal 7820.JPG|thumb|left|450px|Aerial view of Gatun Locks, Panama Canal. On top, several vessels waiting at [[Gatun Lake]] to cross the locks. At the bottom is exit canal to the Atlantic Ocean ([[Caribbean Sea]]). At the left of the existing locks, the construction area for the new set of locks with water saving chambers part of the [[Panama Canal expansion project]] which opened for traffic on June 2016.<ref name=NYT062016/>]] |
[[File:Gatun Locks 03 2014 Panama Canal 7820.JPG|thumb|left|450px|Aerial view of Gatun Locks, Panama Canal. On top, several vessels waiting at [[Gatun Lake]] to cross the locks. At the bottom is exit canal to the Atlantic Ocean ([[Caribbean Sea]]). At the left of the existing locks, the construction area for the new set of locks with water saving chambers part of the [[Panama Canal expansion project]] which opened for traffic on June 2016.<ref name=NYT062016/>]] |
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{{Panama Canal map}} |
{{Panama Canal map}} |
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{{clear}} |
{{clear}} |
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Revision as of 14:11, 26 April 2022
 | This article includes a list of general references, but it lacks sufficient corresponding inline citations. (April 2009) |
Sequence of locks and passages that a vessel passes through while transiting the Panama canal
The Gatun Locks, looking north towards the Atlantic Ocean
The Panama Canal locks (Spanish: Esclusas del Canal de Panamá) are a lock system that lifts ships up 85 feet (26 metres) to the main elevation of the Panama Canal and down again.
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. Construction on the Panama Canal expansion project, which included a third set of locks, lasted from September 2007 to May 2016.[1] It opened for commercial operation on 26 June 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.[2]
Filling and draining
Each lock chamber requires 26,700,000 US gal (101,000 m3) 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.[3]
Mules
The canal's mules run on rack tracks with broad gauge, 5 ft,[4]
Map
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References
Inline citations
- ^ "Panama Canal Expansion Project report - October 2012" (PDF). Panama Canal Authority. Archived from the original (PDF) on 2013-03-10.(in English)
- ^ a b "Panama Canal Opens $5B Locks, Bullish Despite Shipping Woes". The New York Times. Associated Press. 2016-06-26. Archived from the original on June 26, 2016. Retrieved 2016-06-26.
- ^ Panama Canal Authority FAQ
- ^ "The Panama Canal Locomotives". panamarailroad. Retrieved 2012-12-11.
- ^ a b "Hydroelectric Plants in Panama". 2015-07-05. Retrieved 2016-06-26.
General references
- History Of The Panama Canal, by Ira E. Bennett
- A History of the Panama Canal, from the Panama Canal Authority
- Cement And Concrete, from The Builders of the Panama Canal, CZ Brats
- The Panama Canal, by Colonel George W. Goethals
- Original Emergency Dam being tested at the Gatun Locks
External links
Media related to Panama Canal locks at Wikimedia Commons