Panama Canal Zone Defences I

16-inch Navy Mk.II M1 gun on M1919 barbette mount in Panama.

Fortifying the Canal

The Hay-Pauceforte and Hay-Bunau-Varilla treaties implied but did not specifically give the United States the right to fortify the Canal Zone. Central to America’s decision to fortify was Article Three of the Hay-Bunau-Varilla treaty, which gave the United States all powers, rights, and authority in the Zone. Panama protested in 1904 when the United States government used this sovereignty in establishing ports of entry, customhouses, tariffs, and post offices in the Zone. An amendment giving some concessions to Panama in those areas was made after Secretary of War Taft, George Goethals, and other Army leaders visited the Isthmus in November 1904 to determine questions relating to possible fortifications. The amendment was supposed to be in effect only during the construction period, but it lasted until 1924, and efforts for a new treaty were unsuccessful.

The debate over Canal fortification continued until 1911, when Congress passed a $2 million appropriation for that purpose. The following year, Congress added $1 million for gun and mortar batteries and $200,000 for land defenses. Construction began on 7 August 1911 under Sydney Williamson, Goethals’ Chief of the Pacific Division, and on 1 January 1912, Goethals’ son, Lieutenant George R. Goethals, was put in charge of fortification work. The construction towns of Empire and Culebra, no longer needed, were used for the Army garrisons. There were large forts with gun batteries built at each end of the Canal, with field work for 6,000 mobile force troops (infantry, cavalry, engineer, signal, and field artillery). The work of The Panama Canal staff increased significantly with the 1915 military appropriation of $1,290,000 and subsequent assignment of Army barracks and quarters construction. All design and construction work for Army post buildings was assigned to The Panama Canal. Much of the early quarters construction undertaken by The Panama Canal for the Army utilized existing “type house” designs. By June 1915, almost $15 million had been spent on fortifying the Canal, including the locks and dams. Military reservations were officially designated on 18 September 1917 as Fort Grant, Fort Amador, Fort Sherman, Fort Randolph, and Fort de Lesseps.19 That same year The Panama Canal designers were asked “… to furnish preliminary plans and estimates for cantonment construction for Army troops and for the proposed permanent posts for mobile troops on the Canal Zone.”20

This request developed from the investigation and findings of an Army Board of Officers convened to recommend post locations for the troops in the Canal Zone, and to recommend the type and character of buildings required. The Board members represented the Infantry, Engineer Corps, Cavalry, Medical Corps, and Field Artillery. In their report, dated 28 August 1917, the Board recommended placing one brigade of infantry at Gatun, and all other mobile force troops on the Pacific side. There, they supported the location of one infantry brigade at Miraflores Dump, another adjacent to the Curundu River, and one artillery brigade and one cavalry regiment south of the Diablo Ridge. Corozal was the location recommended for the sanitary troops, the Signal Corps troops, and the Engineer regiment, as well as for the main supply depot site. Quarry Heights (created on the site of the former Ancon Quarry) would serve as department and division headquarters.21

The placement of troops on the Isthmus did not wait for the construction of military reservations. As early as 1903, there was a Marine detachment present that kept the Panama Railroad open during the revolution. This detachment remained until January 1914, and at the end consisted of 12 officers and 375 enlisted men. The first permanent Army troops (Tenth Infantry) arrived in October 1911 and were stationed at Camp E. S. Otis in Empire. Three companies of the Coast Artillery Corps arrived on the Isthmus September 1914 and were in temporary quarters at Fort Amador and Fort Sherman by November. That same month the Fifth Infantry arrived with several members of the Medical Corps and the Quartermaster Corps, and the regiment was quartered at Empire. Continued arrivals placed the troop strength on the Canal Zone at approximately 5,000 when the United States entered World War I. 22 Authority over the Panama Canal and the Canal Zone was transferred from the Canal Zone Governor to the commanding general of the U.S. Army forces in the Canal Zone by President Woodrow Wilson in a 9 April 1917 Executive Order.23 An additional Executive Order was used to proclaim the neutrality of the Canal on 23 May 1917.24

A consolidated command called United States Troops, Panama Canal Zone had been put into place on 6 January 1915 under Brig. Gen. C. R. Edwards, as part of the Eastern Department. Initially located at Ancon, the headquarters were moved to Quarry Heights in 1916. A separate geographical department was created 1 July 1917 and named the Panama Canal Department of the United States Army. Also headquartered at Quarry Heights, the Department was first commanded by Brigadier General Cronkhite25. The war passed quietly enough in the Canal Zone, and control of the Canal was returned to the Governor at the war’s end.

For the Panama Canal Department, the inter-war years provided an opportunity to increase defensive strength by creating permanent posts and upgrading defenses against the growing threat of air attack.

When Canal defense requirements were first considered, the threat to be countered was primarily a naval one. Armament and fortifications were planned to repel a frontal naval assault and landing. As aviation technology developed, aerial attacks were perceived as a growing threat, and steps were taken to counteract them. The Army Air Force in the Canal Zone was implemented to “gain and maintain sufficient air superiority to secure the Canal and its accessories against an air attack, to observe fire for the Coast and Field Artillery, to cooperate with the Infantry, to attack any enemy land or naval forces and to cooperate with the Navy in the execution of its mission.”26 By late 1920, the Army aviation base of France Field, and the infantry bases of Fort Clayton (Pacific) and Fort Davis (Atlantic) were in place and manned. By 1925 the Coast Artillery District was abolished and Coast Defense units organized into regiments with separate antiaircraft batteries. A Pacific-side air field (Albrook Field) was constructed by 1932.27

In 1932, the Panama Canal Department was divided into Atlantic and Pacific sectors. The Atlantic Sector contained France Field and the Panama Air Depot, and Forts Sherman, Randolph, Davis, and de Lesseps, while Forts Amador, Clayton, and Kobbe, Albrook Field, and the Post of Corozal were located in the Pacific Sector.28 Headquarters remained at Quarry Heights. In January 1934, the Department consisted of 419 officers and 8,884 enlisted men. This manpower level was considered too low, and by 1936 enlisted strength had increased to 12,990.29

Diplomatic issues continued to be negotiated between Panama and the United States. The Hull-Alfaro Treaty, signed on 2 March 1936, helped settle differences over the devaluing Panama dollar and the Canal annuity payments. It guaranteed joint action and consultation between the countries in times of emergency. The United States also gave up the right to intervene in Panama to maintain public order. After debate in the United States over whether the treaty adequately protected American interests in the area, the Senate ratified it three years later.30

As World War II broke out in Europe, efforts were underway in the Canal Zone to heighten defenses. One of these efforts had both defensive and economic justifications. The original Canal designers were aware that transit capacity would need to be increased in the future, both in terms of ship size and the number of ships able to transit at any one time. After several years of military and civilian study, Congress authorized the construction of an additional set of locks in 1939. Known as the “third locks project,” new, larger locks would be constructed near the existing ones at Gatun, Pedro Miguel, and Miraflores to increase capacity. For defense purposes, they would be built some distance away (1,500 to 3,000 ft) and connected to the existing locks by approach channels. An initial appropriation of $15 million was made through the War Department Civil Appropriations Act of 1941. The total cost of the expansion was estimated at $277,000,000. A Special Engineering Division of the Department of Operation and Maintenance was created to handle the work in close cooperation with existing Panama Canal organizations. Canal employees had been producing plans for the design and construction and selecting potential key employees in the United States since the 1939 authorization. Among the first orders of business were three new construction towns (Caecal, Diablo Heights, and Margarita) for the estimated 6,300 employees and dependents associated with the project.31

Excavation at the Pacific end of what would be the approach channel to the new Miraflores lock was begun on 1 July 1940. The new locks were designed to be used by the 58,000 ton Montana class battleships on order for the Navy. As the threat of war heated up, defense considerations soon outweighed those of commerce. However, upon the United States’ entry into the war, continuation of the project grew uncertain. There was strong Navy support for completing the project as soon as possible to accommodate the warships due in late 1945. Through a series of meetings held in January 1942, the War Department decided to accept the Navy position and to press for rapid completion. Some military officers, however, felt the extra locks only provided another target for air attack. Several months later circumstances changed when the Navy indefinitely postponed its battleship construction program. As a result of these factors, the War Department, the Navy, and the President all concurred in a decision to halt almost all work on the third locks, effectively canceling the project.32

As World War II approached, Canal Zone Army installations were reinforced by increasing the troop strength in Panama from 13,451 in 1939 to 31,400 by the time of the United States’ entry in December 1941. Garrison strength was up to 66,619 by January 1943. Housing these reinforcements constituted only part of a larger construction program. As some troops arrived before construction had begun, however, housing was given the highest priority. Congress appropriated $50 million on 10 June 1939 for improvement of Panama Canal defenses.33

Subsequent contract discussions delayed calls for bids until March 1940. The first contractors arrived on the Isthmus in July 1940. Troop labor was used in the meantime to clear construction sites and put in footings. Housing needs were especially acute, and a Board of Officers was appointed to study and report on “the locations and general layout, plan for the new construction in the Pacific Sector contemplated in the Panama Canal Department housing program, the Coast Artillery Expansion Program, and the Air Corps Augmentation Program.34 Once begun, actual construction was fairly swift, as it was essential to get men and materiel out of tents and into buildings as quickly as possible. Even so, it was a huge job and every available soldier was detailed to some aspect of construction. Little civilian labor was available to assist with the military construction, as the Third Locks project competed for workers.35 Due to the severe time constraints, much of the new construction was of a temporary nature. It was common to use existing building plans but substitute readily available, less expensive, and less labor-intensive construction materials. Designs were stripped down to the essentials, and all ornamental details were eliminated. Temporary structures were less durable, and many were intended to be easily disassembled and reerected elsewhere.

Emergency measures were initiated in the last days of August 1939, and in addition to troop buildup, included anti-sabotage measures and a change of Canal authority. The Army garrison was given the mission of “protecting the Canal against sabotage and of defending it from positions within the Canal Zone.”36 The Navy was tasked to provide offshore defense, provide armed guards for ships transiting the Canal, and maintain a harbor patrol at both ends of the Canal.37 As early as 5 September 1939, an Executive Order was issued transferring jurisdiction and authority over the Canal and the Canal Zone to the Army’s Panama Canal Department.38 Before long, photography of Canal installations was banned for the duration of the war, mines were placed at both entrances to the Canal, low-altitude barrage balloons were placed over the locks with anti-submarine and torpedo nets placed in front of the locks, and chemical smoke pots were positioned throughout a 60 square mile area. The massive guns and batteries on military installations at either end of the Canal were prepared for use. The 6 to 16 inch (in.) guns were housed in 11 Atlantic and 12 Pacific batteries, and had a range up to 25 miles. To protect against air attack, anti-aircraft batteries were put in place across the Zone and two antiaircraft detachments were sent in September 1939. Two long-range radar stations were also established that autumn. The main runway at Albrook Field was improved to allow deployment of the more modem bombers that had arrived in June 1939. Military dependents were evacuated to the United States by October 1941.39

Also around 1939, the Panama Canal Department commander began an effort to secure additional defense sites outside the Canal Zone in the Republic of Panama, primarily for airfields. Dozens of sites were eventually requested, but action on this request ran into diplomatic trouble between the United States and Panama. The primary problems were leasing versus buying the sites, and the limits of United States defense authority as defined in the as yet unratified 1936 Hull-Alfaro Treaty. The Treaty was finally ratified on 17 April 1939, and negotiations continued for the additional defense sites even as funding was allocated to lease them from the Panamanian government. An agreement was reached on 21 March 1941 to allow United States forces to acquire sites and begin use before formal approval. On 18 May 1942, the two countries signed the Defense Sites Agreement, in which the United States would utilize 134 sites leased from Panama until one year after the end of the war.40

By the time the build-up was complete, defenses consisted of “nine airbases and airdromes, 10 ground forces posts, 30 aircraft warning stations, and 634 searchlights, antiaircraft gun positions and miscellaneous tactical and logistical installations.”41 Twelve outlying airbases were also constructed in Peru, Ecuador, Guatemala, Nicaragua, and Costa Rica. An outer defense parameter of 960 nautical miles from the Canal was established and patrolled by air and sea.42

In 1941, a major command reorganization was precipitated when the United States took into protective custody the British possessions (and prospective base sites) of Jamaica, Antigua, St. Lucia, Trinidad, and British Guyana. To administer these new bases, and to quell issues of command extent between the various Army and Navy forces in the area, a theater command was established. The Caribbean Defense Command was officially activated on 10 February 1941, under the command of General Daniel Van Voorhis, then the commander of the Panama Canal Department. The Caribbean Defense Command was initially set up as strictly Army, and coordination with Navy operations was by “mutual cooperations” A separate command, the Caribbean Air Force, was established for air defense about the same time. General Frank M. Andrews succeeded General Van Voorhis in August 194l.43

The Army and Navy personnel in Panama had been on full alert since midsummer 1941. The first immediate effects of the United States’ December entry into the war were ones of command structure and reinforcements. The first order of business was to create a unified command through which Army and Navy could be coordinated. President Roosevelt put the Army in charge of the Panama sector, and the Navy in charge of the more distant Caribbean Coastal Frontier on 12 December 1941. General Andrews thus assumed command of both Army and Navy forces in the area on 18 December 1941.44 Both air and ground forces were heavily augmented over the next two months, with the Panama garrison strength reaching 39,000 by the end of December, and growing to 47,600 by the end of January 1942.45

For those living and working in the Canal Zone, World War II was “a time of perceived danger during which the movement of materiel, troops and supplies through the waterway was a critical part of the war effort.”46 While Panama and the Canal both escaped enemy attack, a damaging U-boat campaign was carried out against shipping in the Caribbean. From February through December 1942, some 270 ships in the area had been sunk by U-boats. The peak of the German U-boat threat came in the summer of 1942. In the month of June alone, 29 vessels were sunk in the Atlantic Sector of the Panama Sea Frontier.47 Caribbean Defense Command peak strength of 119,000 was reached in December 1942. Of these, over half were stationed in Panama to protect the Canal from attack or sabotage.48 by mid-summer 1943, the U-boat threat was receding due to increased effectiveness of the theater’s antisubmarine forces, the effects of Allied victories in other waters, and the shift of U-boats away from the Caribbean.49

With the threat of Canal attack diminishing, the reduction of troop strength became feasible. Downsizing was begun in January 1943, and continued until the end of the war. From a peak of 119,000, Army forces had dropped to 91,000 by the end of 1943. When the war in Europe ended in May 1945, Caribbean Defense Command strength was down to 67,500.50 War-time defenses, including large artillery guns, landing fields, and mine fields were removed as the military returned to a peace-time defensive position. The Caribbean Defense Command was reorganized into the U.S. Army Caribbean and the Caribbean Command (a unified authority over the Army, Navy, and Air Force components)51 This command structure would last until 1963, was redesignated as the United States Southern Command (USSOUTHCOM), and the Army component became the United States Army Forces Southern Command (USAFSO). The major Army command would be inactivated in 1974, then re-activated as the United States Army South (USARSO) in 1986.52

In October 1947, the United States tried to negotiate an agreement for five more years occupation of 13 auxiliary World War II sites and the military air base at Rio Hato, 70 miles west of Panama City, for 10 to 20 years. In December, with pressure from the Communist Party in Panama and student anti-American demonstrations, the Panamanian Assembly unanimously rejected the agreement, and the United States agreed to evacuate the remaining 14 sites immediately, while continuing to negotiate. With national elections coming up in 1948, Assembly members wanted to reduce American influence in Panama as much as possible to appease the voters.53

In the 1950s, the United States made several concessions to the Panamanians: a single pay scale for American and Panamanian workers was established; Spanish became an official language in the Canal Zone along with English; Panama was given more money from Canal toll collections. The United States was given 19,000 acres in the Rio Hato area for military training. Panama, however, twice rejected requests by the U.S. to deploy Nike missiles in 1956 and 1958. Two ground-to-air HAWK-AW missile batteries were deployed in 1960 at Fort Sherman and Fort Amador. Growing nationalistic sentiment expressed in student demonstrations in 1955, 1958, 1959, and 1964 helped to finally convince the United States to renegotiate the Hay-Bunau-Varilla Treaty.54

In 1974, the United States, under chief negotiator Ellsworth Bunker, agreed in principle to relinquish control of the Panama Canal and the Canal Zone to Panama. At that time, there were about 46,000 people living in the Canal Zone. Most (30,000) were active duty military, their dependents, and civilian employees. Roughly 10,000 Americans (employees and dependents) were associated with the Panama Canal Company. During the administrations of President Jimmy Carter and General Omar Torrijos, two treaties were negotiated. The first, called the Panama Canal Treaty, abolished the Canal Zone and returned the territory to Panama, with the United States having the authority to manage, operate and defend the Canal with increasing participation by the Republic of Panama. At noon on 31 December 1999, Panama will assume control of the area and responsibility for the Canal as the United States’ presence ends. The second treaty gave the United States the permanent right to defend, jointly with the Republic of Panama, the Canal’s neutrality. The treaties were signed on 7 September 1977 by Presidents Carter and Torrijos at the Organization of American States. After months of heated debate, the United States Senate passed the two treaties in March and April 1978, each by a vote of 68 to 32, drastically changing American military and political influence in Panama.55

Implemented on 1 October 1979, the Panama Canal Treaty impacted U.S. armed forces in Panama through the immediate turnover of some military facilities, the relocation of other facilities, and the undertaking of some social responsibilities formerly run by the Panama Canal Company. Some facilities at Fort Amador were turned over to the Panamanian government immediately, necessitating the relocation of U.S. Army headquarters to Fort Clayton. Facilities were also shifted from the Albrook Army Airfield to Air Force installations in the former Canal Zone. The Department of Defense became responsible for the education, health care, and postal services previously run by the Panama Canal Company. Since 1979, the turnover of military facilities has continued and will proceed until the expiration of the Panama Canal Treaty at 12 noon on 31 December 1999.56

U.S. Military Aviation in Panama

World War I and France Field

The outbreak of World War I brought the first pioneering aviation operations to the Canal Zone. As the efficiency of combat aviation progressed during that conflict, it became clear that the U.S. must provide some form of air force for the defense of the Canal. In March 1917, just prior to American entry into the War, the 7th Aero Squadron deployed to Panama to provide aerial reconnaissance capabilities in cooperation with Navy and Coast Artillery forces in the Canal Zone. This first aviation unit consisted of just two officer pilots and 51 enlisted men, under the command of Captain H. H. “Hap” Arnold. Its entire aircraft complement consisted of two Curtiss R-4 observation planes. For the first few months after arrival in Panama, the 7th shifted its operations between a number of Army bases while its new flying field was under development. March found the 7th at Corozal, but it immediately moved to Camp Empire, and then to Fort Sherman by August 1917. In the meantime, development had begun on a new Army air field adjacent to the Navy’s air station at Coco Solo. The first preliminary improvements centered around providing an adequate landing surface, which was accomplished by laying a base of crushed coral and covering it with hydraulic fill. Grass was planted over this base by August 1918, at which time flying operations commenced on a small scale. It was not until January 1919, however, that the 7th permanently moved into its new quarters at France Field. After the war, a significant construction program commenced in order to provide permanent facilities for the Air Corps’ growing commitment in Panama. Most of the original permanent construction at France Field was completed between 1920 and 1922, including a new flight line with six hangars. Nevertheless, significant problems plagued France Field throughout its existence, centering around its inferior landing surface. Its flying field could not be expanded due to its location. More importantly, the coral foundation was prone to constant uneven settling, which required an inordinate amount of costly new filling and leveling work. It was also rather brittle and could not safely support the ever-increasing weights of new aircraft. Already by the early 1930s, France Field was deemed unsafe for the operation of the large bombers and commercial aircraft of the day. As soon as other airfields were available in the Canal Zone, it became a secondary operation. Eventually, the limitations of its landing surface prohibited France Field’s efficient use as an Air Force Base. By late 1949, France Air Force Base supported only a small caretaker detachment. In accordance with Canal Zone Order Number 54, it ceased to be an Air Force. installation on 22 August 1960, and its lands were assigned to the Department of the Army, Department of the Navy, and The Panama Canal Company.57