Panama, 1974- 1975
Here are some pictures I took while working in the Panama Canal Zone and living in Panama in1974 and 1975.  My work location was the US Army facility in Corozal, which is right next to the Miraflores locks on the Pacific Ocean side of the canal.  Click on any of the thumbnails to see a full sized picture.
On this page are pictures of the canal, primarily the locks at Miraflores and Gatun.  The next page contains pictures taken in and around Panama City, where I lived, and Colon.  There are also pictures from several fishing trips off the pacific coast of Panama.
The Miraflores locks are the first pair of locks encountered by ships entering the canal from the Pacific Ocean.  This building is the Miraflores lock house from which the locks are operated.
The Miraflores Locks

The Miraflores Lock Control House
The canal locks are paired with two locks side-by-side to allow two-way traffic.  The locks can also be operated in parallel in the same direction depending on the traffic flow requirements for the canal.  A ship has to pass through three locks on each side of the canal to be raised to the level of Lake Gatun.  Miraflores has two lock pairs.  The third pair of locks on the Pacific side are at Pedro Miguel, about 3/4 mile upstream of the Miraflores locks.
For several years the Panama Canal Authority (ACP), which now administers the canal has been in the process of expanding the locks to provide a third set of locks parallel to the existing pair.  The new locks will also accommodate much larger vessels than the Panamax of 1975.

Atlantic Bound Freighter Departing the Miraflores Locks

Atlantic Bound Freighter Entering the Miraflores locks
At the entrance to the canal on the Pacific side in 1975 was the Bridge of the Americas.  Technically this was the only permanent structure joining North and South America.  All of the other structures across the canal were mobile, either swing bridges or the gates of the locks.
Checking the Panama Canal Authority (ACP) website, it appears this bridge was replaced a number of years ago, and is again being replaced or modified for the expansion of the Canal to three locks in 2013,

Bridge of the Americans (1975)

Bridge of the Americas (1975)
On the Atlantic Ocean side of the canal are the Gatun Locks.  This is a set of three lock pairs.  Once an incoming ship transits these locks it is in Lake Gatun.  The ship in the two pictures center and below is a Panamax (maximum size for the locks in 1975) car carrier heading out into the Caribbean Sea.  Probably returning to Europe after delivering Volkswagons to the West Coast of the USA.
Gatun Locks Control House

Auto Carrier Departing the Gatun Locks for the Caribbean

Gatun Locks Looking Toward the Caribbean

On the right is the sequence of events for a ship entering the Miraflores lock complex from the upstream Pedro Miguel locks.  On the top is the dock that separates the lock pairs.  There is a mechanical arrow on the building at the end of the dock that directs the ship to one side or the other.  As the ship approaches the locks two canal workers in a small dory row out to meet it.  It wasn't clear to me what was going on between the dory and the ship, but it appears they are taking lines to connect the ship with the electric mules that help control and guide the ship through the lock.

The bottom picture is  of a vessel heading into the canal from the Miraflores locks.  They are about to cast off the lines and proceed under their own power to the Pedro Miguel locks,

Pier Separating the Miraflores Locks

Dory Preparing to for Incoming Ship

Dory Heading for Incoming Ship

Dory Taking Line from Ship

Dory Taking Line From Ship

Electric Mule Connected to Ship
On the right is another sequence of pictures at the Miraflores locks.  In this set a ship enters the locks on the top, heading out to the Pacific Ocean.  The ship is guided into the upstream lock by the mules and then is dropped 24 feet to the level of the downstream lock.
Pacific Bound Ship Entering Upstream Miraflores Lock

Ship Centered in Upstream Mifaflores Lock

Ship Droping in the Upstream Lock

Ship Departing Upstream Lock

Ship Departing Miraflores Locks
Here are two pictures of the electric mules at the Miraflores locks.  The mules are electric locomotives that move along the sides of the locks on rails.  They have large cable winches that can take up or let out the cables attached to the ship.  Normally a large ship will use 4 mules to transit the lock complexes, two one each side.  The ship moves under its own power, but too slowly to maintain steerage.  The mules essentially steer the ship in the lock at the direction of the Canal Pilot on board.  Directions are passed by radio, but also by a series of whistles.
Electric Mule at Miraflores Lock

Electric Mule Controlling a Ship
On the on the right a ship has cleared the Pedro Miguel locks and is heading toward the Miraflores locks.  In this short distance (less than a mile) it is difficult for the ship to maintain steerage and still move slowly enough to stop at Miraflores.  A number of tugs operate between the two locks to help ships get from one lock to the other.
Ship Bound From Pedro Miguel to Miraflores

Tugs Maneuvering Ship Toward Miraflores

Tug Maneurvering Ship

Go on to more pictures of Panama