Miraflores Locks, Panama Canal — lock
Ibn Fawda al-Ameriki · CC BY-SA 3.0

Miraflores Locks, Panama Canal

Miraflores

  • 2 min read
  • 8.997° N 79.592° W

Interesting facts

  • Filling a single chamber takes about 101,000 cubic metres of water, all of it released from the lake above and later sent down to the sea.
  • The main culverts inside the walls are up to about 6.7 metres across, wide enough for a railway train to pass through.
  • Fed through 14 cross culverts with 70 openings in the floor, a chamber can be filled in as little as ten minutes.
  • Despite their weight, the hollow steel gates are buoyant like a ship's hull, so two 19-kilowatt motors are enough to swing each leaf.
  • The towing locomotives are called mules after the pack animals once used to cross the isthmus; a large ship may be held by eight of them.
  • The mules do not pull ships forward, which move on their own engines; the locomotives only steer and brake, climbing 50 per cent rack-railway ramps between chambers.
  • Heavy fender chains were once stretched across the chambers to stop a runaway ship of up to 10,000 tons; they were finally removed in 1980.
  • Operators control each flight from a room on the centre wall using a working model of the locks whose gates and valves mirror the real ones.
  • Miraflores and Pedro Miguel, the Pacific-side locks, were finished before Gatun; stone for their concrete was quarried from Ancon Hill above Panama City.
  • The centre wall between the paired chambers is about 18 metres thick and contains three tunnels for drainage, electric cables and machinery access.

Why it is worth it

Miraflores is the last step of the Panama Canal before the Pacific, or the first coming the other way: a pair of lock chambers in two stages that lift ships between sea level and Miraflores Lake. The average lift is about 16.5 metres, but here the number refuses to stay put — the Pacific has a large tidal range at this end of the isthmus, so the total climb swings from roughly 13 metres at extreme high tide to nearly 20 at extreme low. To cope with it, Miraflores was given the tallest gates of the original canal, some leaves standing about 25 metres high.

The locks were completed in 1913 and opened with the canal in 1914. They are built on the heroic scale of that project: each chamber is 33.5 metres wide and about 320 metres long, closed by steel mitre gates about two metres thick whose single leaves weigh up to around 600 tonnes. Water moves by gravity alone, running from the lake through culverts in the walls and the chamber floors, with no pumps at all. Ships are held in the centre of the chamber by electric locomotives on rails along both walls, known as mules, which run beside the hull with taut cables as it rises or falls.

Watching this happen is the reason to come. Miraflores sits a short way from Panama City, and a four-storey visitor centre has been built beside the chambers with a ground-level terrace at the height of the lock floor and a bleacher deck above it, high enough to see the whole width of a chamber, the mules on both walls and the superstructure of a ship as it rises. A large vessel with little room to spare on either side, sliding upwards as the water boils beneath it, is one of the great industrial spectacles in the world. The building also has exhibition halls on the canal and a large-screen theatre; the full visit takes around an hour and a half.

Ships move through in both directions over the day, and there are long pauses between them, so it pays to be patient. Beyond the locks the canal runs out under the Bridge of the Americas to the Pacific.

Getting there

Miraflores is on the outskirts of Panama City, about 6 km from the Curundú district; taxis and tours run there from the city. The closest airport is Marcos A. Gelabert International Airport (PAC) at Albrook, about 5 km away, which handles domestic and regional flights; most international travellers arrive at Tocumen International Airport (PTY), on the far side of Panama City.

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From the encyclopaedia

Miraflores is the name of one of the three locks that form part of the Panama Canal, and the name of the small lake that separates these locks from the Pedro Miguel Locks upstream. In the Miraflores locks, vessels are lifted 54 feet (16.5 m) in two stages, allowing them to transit to or from the Pacific Ocean port of Balboa in Panama City. Ships cross below the Bridge of the Americas, which connects North and South America.

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