Digest>Archives> February 1999

Lighthouses of The Panama Canal

By Kelly F. Dawson

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Front Northbound Reach Lighthouse, Miraflores ...

History: On November 18, 1903, a treaty between the United States of America and the Republic of Panama was signed, making it possible for the United States to build and operate a canal connecting the Atlantic and Pacific Oceans through the Isthmus of Panama. For the sum of $40 million, the United States purchased the rights and properties of the French, who had labored from 1879 to 1899 in an effort to build a canal. In addition, negotiations with private landholders within what would be the Canal Zone resulted in a mutually agreeable price for their properties.

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Rear Northbound Balboa Reach Lighthouse at ...

U.S. construction of the Canal began in 1904 with laborers from countries all over the world. The monumental project was completed in ten years, at a cost of about $387 million. The Canal first opened on August 14, 1914.

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Pacific Entrance, Flamenco Island Light. This ...

At the end of 1962, the United States completed the construction of a high level bridge over the Pacific entrance to the Canal, known as Thatcher Ferry Bridge, and the flags of the Panama and the United States were flown jointly over areas of the Canal Zone under civilian authority.

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Rear Sea Range Light, located in the town of ...

Two new treaties between Panama and the United States were agreed upon on August 10, 1977, and signed on September 7, 1977. One deals with the operation and defense of the Canal until the end of 1999; the other guarantees the Canal permanent neutrality. On April 18, 1978, the United States Congress ratified the treaty. The treaty went into effect on October 1, 1979.

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The Isla Grande Lighthouse was the only light ...

Under the treaty, the United States maintains operational control, until noon on December 21, 1999, over all lands, waters and installations necessary to manage, operate, and defend the Panama Canal. A U.S. government agency, the Panama Canal Commission replaced the Panama Canal Company to operate the Canal during the 20 year transition period. A policy-making board of five U.S. citizens and four Panamanians serves as the Commission's board of directors. During the first ten years of the treaty transition period, until 1990, the Canal's chief executive officer, called the administrator, was a United States citizen and the deputy administrator was Panamanian. Since 1990, the positions have been reversed, with a Panamanian serving as administrator and a U.S. citizen serving as deputy. This is believed to be the first time that a non-U.S. citizen is the head of a U.S. government agency.

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Shown here is a tugboat going through the Gatun ...

The Panama Canal Operation: The Panama Canal is a lock-type canal that serves to connect the Atlantic and Pacific Oceans. It is approximately 50 miles long, deep water to deep water, and follows a northwesterly to southeasterly direction. The Atlantic entrance is approximately 27 miles west of the Pacific entrance. There are three sets of locks. A ship entering the Canal from the Atlantic, sails at sea level from Cristobal Harbor to Gatun Locks, a distance of 7 miles. It is then lifted 85 feet to Gatun Lake in three lockages or "steps." From Gatun it sails, 85 feel above sea level, to Pedro Miguel, a distance of 31 miles.

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Show here is the Gatun Locks Lighthouse behind ...

A single lockage at Pedro Miguel Locks lowers the ship 31 feet to Miraflores Lake. A mile further south the vessel enters Miraflores Locks and, in two lockages, is lowered 54 feet to the Pacific Ocean level. A ship sails 4 miles to the Balboa Port area before entering the outer harbor.

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This is an antique lantern which was liberated ...

The locks' chambers are 110 feet wide and 1,000 feet long. The approximate dimensional limitations of vessels transiting the Canal are: beam 106 feet, draft 39 feet 6 inches tropical freshwater, and 950 feet in length.

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A ship from Hong Kong passing through the Gatun ...

Water to move vessels up and down at each set of locks is fed by gravity from Gatun Lake which is one of the largest artificial bodies of water in the world. It can take up to four hours to transit this lake, depending on the size of the vessel. Water enters the locks through a system of main culverts. As the water is released into the main culverts, it is diverted into 20 lateral culverts and distributed through 100 holes in the floor of the chamber. For each ship transiting the Canal, about 52 million gallons of fresh water are used, fed by a gravity flow system through the locks and spilling into the ocean.

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The Panama Canal in operation shows the S.S. ...

Eight to ten hours are required for an average ship to transit the Canal. During this time the passengers aboard have a unique opportunity to see one of the modern wonders of the world in operation. The Canal operates 24 hours a day, 365 days a year, transiting vessels of all nations on a non-discriminatory basis.

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A Panama Canal worker is shown here checking on ...

The Panama Canal Commission - A U.S. Government Agency

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Panama Canal workers checking on the lighthouse ...
Photo by: Jamie Yau

The Panama Canal Commission is an agency of the Executive Branch of the U.S. Government, provided for by the Panama Canal Treaty of 1979, enacted on September 27, 1979. The authority of the President of the United States on the Commission is exercised through the Secretary of Defense, or his representative. A nine member Board supervises the Commission. Five members are nationals of the United States, and four are Panamanians. The President, with the advice and consent of the Senate, appoints those board members who are U.S. nationals.

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Range Light at the Gatun Locks.

The Commission was established to carry out the responsibilities of the United States with respect to the Panama Canal under the Panama Canal Treaty of 1977. In fulfilling these obligations, the Commission manages, operates, and maintains the Canal, its complementary works, installations, and equipment, and provides for the orderly transit of vessels through the canal. The commission will perform these functions until the Treaty terminates on December 31, 1999, when the Panama Canal Authority, a newly formed agency of the Government of Panama will assume full responsibility for the Canal.

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The construction of the rear range tower at the ...

The Panama Canal is funded through the collection of tolls and does not use any taxpayer dollars for its operation.

Historical Information on the Panama Canal Lighthouses: In 1915, a paper was developed by Walter F. Beyer, former Assistant Engineer of the Isthmian Canal Commission, and presented to the International Engineering Congress in San Francisco, CA, on September 20-25, entitled "The Panama Canal-Design and Erection of Structures."

In his paper, Mr. Beyer takes the reader through the process of the design and construction of the lighthouses and other navigational aides that took place as the Canal was in the process of being built. While the report is very technical in nature, several passages are of great interest to anyone with an interest in lighthouses. These are summarized in the following paragraphs, followed by an update of information on the lighthouses today.

The report explains that, since the Canal was an entirely new waterway that went from ocean to ocean, the establishment of a whole new and independent system of aides to navigation along the waterway that could take advantage of modern technology, both in the layout of the system and in the construction of the various towers. Mr. Beyer describes the decisions that went into the design of the lighthouses, of which 46 were built to assist the pilots. In the Panama Canal operating area, there were a total of thirty-five lighthouses. Today, thirty-four lighthouses are still standing, of which twenty-eight are operational.

Construction: According to the lighting plan, it was determined that when, for any reason the ranges were not visible, the pilot had to depend entirely upon his compass and the sidelights and unlighted spar buoys, which mark the sides of the channel. These sidelights, as in other waterways, consisted of lighted beacons and gas buoys, the former used wherever a foundation could be constructed, either above or below water. These beacons and buoys were placed at all turning points and at convenient intervals along the sides of the channels, in pairs, two abreast, and are in general, about one mile apart. The unlighted spar buoys are placed in line with the beacons and gas buoys and midway between them.

After the preliminary examination of the probable locations for the range towers along the entire length of the Canal, it became apparent to the engineers that two types of towers would be required. One would be a rather ornate type, to be used where they were in such close proximity to the canal, or the Panama Railroad, that the material could be readily delivered at the site, and where they would present a pleasing appearance to the people aboard passing ships or trains. The other type was a simple design, with a minimum amount of material required in its construction and used where sites were inaccessible and the handling of material difficult. Many of these towers were built in Gatun Lake; one of the largest artificial bodies of water in the world, before the water was filled in.

In tropical countries, the conditions governing the design of lighthouses are different from those of the colder countries, necessitating the limitation, as far as possible, of certain building materials, such as steel and wood, which rapidly deteriorate in those countries, and permitting the use of concrete in bold designs. As it was the aim to obtain permanency, minimum cost of upkeep and minimum amount of material entering into the construction of all these structures pertaining to the system of aides to navigation, concrete was adopted.

The towers were designed so that they could be built to any height, up to 90 feet, from one set of forms. Thirteen such towers were built; the towers being 28 feet and the highest 87 feet 10 inches from the base to focal plane, and the heights of the intermediate towers being 42, 46, and 74 feet. The walls of these towers range from 7 to 5 inches in thickness.

Owing to the frequent slight earth tremors, the stability of the towers against overturning by earthquakes was increased by adopting a heavy base section and making the shell of the tower conical with tapering wall sections, thus lowering the center of gravity. The result of the computations for the 74 foot tower showed that the tower would be stable against winds at 100 miles per hour without reinforcing. However, in order to provide against overturning by earthquakes, to prevent fatigue in concrete and defects due to poor workmanship, reinforcing rods were used to bind the concrete together.

The mix used in all reinforced concrete consisted of one part cement, two of sand, and four of broken stone; or one part of cement to four parts of sand and gravel. The latter aggregates were used in the majority of the work, the sand and gravel as obtained from riverbeds being in about the proper proportions to form a good, homogeneous mass.

The concrete was carefully mixed by hand with sufficient water to make the mixture quake while being spaded in the forms. Little ramming was required, and the resulting concrete proved to be practically waterproof during heavy, driving, torrential rains that the area is known for.

In 1913, after the majority of the range towers, especially the high ones, had been completed, a number of quite severe earthquakes occurred at different times on the Isthmus. Some of them were of sufficient force to rock buildings and one did considerable damage to the walls and ceilings of the new Administration Building at Balboa, then under construction, but in no instance did any of the range towers suffer the least damage.

Prior to these earthquakes, at a time when the highest tower, 87 feet 10 inches was about completed, a foreman and several laborers were doing some work in the lantern of the tower when a sub-aqueous blast was set off near Mindi, a point about 1 3/4 miles from the site of the tower. The blast caused the tower to vibrate both vertically and horizontally, to such an extent that all of the laborers fled, in terror, to the bottom of the tower. Before they reached the bottom, the vibration had ceased.

The concrete spiral stairways in the interior of the towers were unique and had the added virtue of being constructed quickly and economically. They were built up of reinforced concrete at a central plant in the Canal Zone.

Illumination: Before several of the beacons were modernized, a system using compressed acetylene gas dissolved in acetone was adopted. The towers and beacons equipped with electric light, instead of burning day and night, as in the case where acetylene gas was used, were lighted at sundown and extinguished at sunrise, the control for each circuit being located at a convenient point. All of the towers and beacons from the shore of Limon Bay to, and including, the ones on the lock walls at Gatun are connected and are operated from switches in the Gatun Locks. Today, all of the lighthouses are fitted with solar sensors. These are variable resistors that are used to control the on and off condition of the electric circuits. In the case of the marine range lights in the Panama Canal, these sensors display a high electrical resistance in the presence of light (sunlight) and a low resistance in the absence of light.

The type of lamp used in the electric-lighted towers and beacons is spherical and has a spirally wound Tungsten filament, concentrating the light source to a sphere of 1/2 inch for 100 watt, and 5/8 inch for 150 watt lamps. In all the electrically lighted range towers, a provision was made against the extinguishment of the light by placing two lamps, one behind the other, behind the lens. Thus, if the front lamp burns out, the rear one will remain burning, with no apparent diminution of candlepower as far as the naked eye can detect. This was determined by experiments on dark nights at points close to the range towers and also at distances of about four miles.

The candlepower of the naked gas flame and the electric lamps was increased by the use of lenses of various types and sizes. Those for the beacons and buoys were Fresnel lenses 300mm in diameter, and those in the range towers, 12 inch diameter semaphore and fourth order range lenses. The Fresnel lenses in the gas buoys are of ground glass and were made in France; but those for the beacons and range towers are of pressed glass, made in the U.S. at a great savings in cost, and with little loss of efficiency as compared to the ground glass lenses.

The estimated candlepower resulting from the use of the foregoing electric and gas lights in combination with the lenses were as follows:

The ranges marking the entrances to the Atlantic and Pacific ends of the canal which lead out to sea were equipped with fourth order range lenses and 150 watt concentrated filament lamps, producing approximately 300,000 candlepower. All other ranges marking the various channels throughout the canal were equipped with 12 inch diameter pressed glass semaphore lenses; and in those where 100 watt lamps were used, the resulting candlepower was approximately 45,000 candlepower; those in which 60 watt lamps were used, 30,000 candlepower. Where it was necessary to use spherical mirrors in conjunction with the lenses, such as where it was desired to equalize the intensity of any two lights forming a range, the candlepower was increased about 35%. To accomplish this, the spherical mirror was placed behind the light source and carefully adjusted.

As a result of modernization to date, and depending on their distance from the main channel and the light intensity in candles required by the navigator, the lenses are flat, spreadlite or Fresnel. Their candlepower could be anywhere from 1,400 to 900,000 candles.

For lighthouse purposes, the canal is divided into natural divisions. The first one extends from deep water at the Atlantic end to Gatun, known as the Atlantic section; the second from Gatun to Gamboa, known as the Gatun Lake section; the third from Gamboa to Pedro Miguel Locks, known as the Culebra Cut section; the fourth from Pedro Miguel Locks to Miraflores Locks, known as the Miraflores Lake section; and the fifth from Miraflores Locks to deep water at the Pacific end known as the Pacific section.

The Lighthouse Division of the Panama Canal Company was created on April 14, 1914, and headed by W.F. Beyer, Assistant Engineer. On July 1, 1915, as the result of a reorganization, it became a Subdivision of the Marine Division and functioned as part of this division and later Marine Bureau until another restructuring in 1959, when it became part of the Dredging Division's Repair Branch. The lighthouses are unmanned and maintained by the Dredging Division today.

Several lighthouses were turned over to the Republic of Panama in 1979. It is the Panama Canal Commission's understanding that the National Port Authority of the Republic of Panama maintains them. There is no indication that existing lighthouses will be replaced by the new Panama Canal Authority, come the year 2000, unless a valid need exists, such as the widening of existing channels or requirements for land where the lighthouses are located.

There are lighthouses in Panama that were reverted in accordance with the 1977 treaties, which are outside of the Panama Operating area. The names of those lights are as follows: Isla Grande, Farallon Sucio, Moro Puercos, Cape Mala, Jicarita, Taboguilla, and San Jose.

About the author: Ms Kelly F. Dawson was born in the Republic of Panama in 1967 and lived there until 1987, when she moved to Virginia with her family. She has been working for the Panama Canal Commission as the Executive Assitant to the Secretary since 1988. Kelly's grandfather came to Panama from Ireland to work for the American Cable Co., one of many companies that were formed during the building of the Canal. Her grandmother came from Michigan so her father could work on the Panama Canal Railroad. Her father was born and raised in Panama, and later became Aide to the Admiral. Kelly is proud to know that her family has been involved with the Panama Canal from the beginning to the end of the U.S. tenure.

This story appeared in the February 1999 edition of Lighthouse Digest Magazine. The print edition contains more stories than our internet edition, and each story generally contains more photographs - often many more - in the print edition. For subscription information about the print edition, click here.

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