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MCH, vol. 7, no. 1

The American Naval Base in Ponta Delgada, 1917–19

Sérgio Rezendes, PhD



Abstract: This article derives from a master’s thesis about the consequences of World War I in the Azores archipelago that included a chapter dedicated to the U.S. Navy facilities at Ponta Delgada on the island of São Miguel. With its two U.S. Marine Corps units, U.S. Naval Base 13 defended the port, a British wireless station near Ponta Delgada, and support structures for the assigned or passing naval units. This article offers a vision of Naval Base 13 as a U.S./Europe border during World War I that was critical to the protection of British and American military and commercial shipping and denying Germany any base of operations in the region from which to launch attacks on Allied forces.​ 

Keywords: Ponta Delgada, World War I, Azores, Naval Base 13, Azores Detachment of the U.S. Atlantic Fleet



With two U.S. Marine Corps units (1st Marine Aeronautic Company and another comprising a mix of infantry, artillery, and services corps), U.S. Naval Base 13 in the Azores defended the port of the island of São Miguel, a British wireless station near Ponta Delgada, and support structures for the assigned or passing naval units during World War I.1 This article offers a vision of Naval Base 13 as a U.S./Europe border during the war, which President Franklin D. Roosevelt studied during World War II and remembered from his visit to the archipelago on 16 July 1918, using these islands as a starting point for a higher contribution to the unit’s history.2

By translating and sharing his research among predominantly Portuguese sources, the author hopes to promote future works about the Azores Detachment of the U.S. Atlantic Fleet’s Navy and Marine Corps presence in the archipelago.







CAC3224, Coleção Museu Carlos Machado
Marine Corps Infantry facilities at Ponta Delgada, São Miguel, 9 February 1918.






CAC3225, Coleção Museu Carlos Machado
Marine Corps aviators’ houses in front of São Brás Fortress (near Flying Beach), Ponta Delgada, São Miguel, 9 February 1918.


Ponta Delgada, Azores, Portugal, December 1917.

Photo by Raymond D. Borden, courtesy of Naval History and Heritage Command


Portugal in World War I

At the beginning of World War I, the young Portuguese Republic had been in existence for less than four years.4 Optimistic in their ability to solve the political, economic, and social problems as a result of the end of its monarchy, a succession of governments and two Azorean presidents of the republic would try to stabilize a regime, but the context of international war did not help. Six days after the beginning of the war, the Portuguese Parliament would support England without denouncing Germany.5 In a society on the edge of a civil war, two opposing political positions were formed: one in favor and the other against Portugal’s intervention. The main argument for the intervention was the need to maintain sovereignty over Portugal’s African territories and the necessity to affirm the young republic’s place in the international community, enforcing the alliance with England at a time when Spain was considered dangerous.6

Due to incidents in Africa since 1914, an agreement was made between Portugal and Britain by which the Royal Navy would assume the defense of Madeira and the Azorean sea. The Portuguese Navy remained responsible for the defense of the mainland coast, especially the harbors, and for escorting merchant vessels to the islands of Madeira and the Azores and to Africa. In September 1914, the first Portuguese expeditionary forces left for Angola and then for Mozambique, where the Portuguese colonies’ borders were under German attack. In Europe, the Portuguese presence in the trenches was a logistical and operational problem for Britain. Under their alliance, in December 1915, Britain requested that Portugal hand over the German ships interned at Portuguese ports, which Portugal accepted in late February 1916. As a result, Germany declared war on Portugal on 9 March 1916.


The Azores and World War I

Rear Admiral Herbert O. Dunn, first commander of U.S. naval forces stationed at the U.S. Naval Base at Ponta Delgada, delineated clearly the strategic value of the Azores and of Ponta Delgada and Horta’s (on Faial Island) harbor capacities to provide ship supply as a coaling station or for ship repairs.7

These islands—the “half-way point between America and Europe”—were vitally important in our naval operations, and soon after war was declared, we began negotiations with Portugal for permission to establish an American naval base at that strategic point. . . . “The occupation of the Azores,” said Admiral Dunn, “was of great strategic value from the mere fact that had it been in possession of the enemy, it would have formed an ideal base for submarines, and as our convoy routes passed north and south of the islands an enemy base would have been a very serious obstacle for the successful transport across the ocean of troops and supplies.”8








Photo by Raymond D. Borden, courtesy of Naval History and Heritage Command Ponta Delgada Harbor, U.S. Naval Base, Azores, Portugal. 28 December 1918.








CAC3233, Coleção Museu Carlos Machado U.S. Navy submarines at Ponta Delgada dock, São Miguel, 14 February 1918.


Traditionally friendly to America, the Azores hosted the first American consul in the world and during the late nineteenth century provided whale-hunting grounds to U.S. sailors.9 The first emigration cycle to the United States began around that time, as American interests in a submarine telegraph communication cable by the Commercial Cable Company yielded the contract for the first cable between New York and the Azores in 1899.10 With a central geo-strategic location in proximity to Europe, the Mediterranean Sea, North Africa, and North America, the submarine cable communication centered in Horta represented a new era that the two world wars would provide to the Portuguese archipelago, an important role that persists even now.11

From a secondary geostrategic position, the first economic signs of the First World War appeared at the end of summer 1914 and resulted in the restriction of Azorean exports to the traditional markets, now at war.12 The presence of surface squadrons in Azorean waters marked the daily lives of people in towns such as Ponta Delgada, a situation that was reversed after the Battle of Jutland and the neutrality of ports such as Ponta Delgada or Horta, open for the protection of German merchant ships.13

The first signs of the presence of German submarines appeared in 1915, which intensified fear among Azorean military authorities, although their presence had already been communicated to the Portuguese Ministry of War and the Navy at the beginning of the conflict.14 Defenses on all the islands were weak or nonexistent. On 3 December 1916, the German U-boat SM U-83 (1916) bombed the harbor of Funchal on Madeira, increasing these fears and generating a precipitation of events that climaxed with the bombing of Ponta Delgada by SM U-155 (1916) on 4 July 1917, possibly attempting to destroy a coal depot mainly used by U.S. ships.15

Portugal’s entry into World War I in 1916 had generated strong apprehension among the military and civilians in the Azores. The operational materiel situated there were antiques left over from the second half of the nineteenth century, with the exception of two machine guns located in São Miguel and Terceira, which had already been modified from their original purpose. Concerns about the possibility of rapid excursions of the Germans for supplies to the British-held islands of Jamaica, Bermuda, and the Antilles had been transmitted to the Ministry of War, urging the government to improve the archipelago’s meager means of defense, given their antiquity, shortage, and malfunction. The British Royal Navy felt that it could not release units due to submarine activity on the coast of England and the fighting in Europe. Britain, which had been an ally of Portugal since the fourteenth century, did not have sufficient naval forces available to protect the Portuguese island seas.16 The Allies left this defense to the United States, without consulting Portugal about the change of interests. The United States, after an agreement with Britain, assumed the defense of the Azorean sea. It was crucial to defend the Azorean sea, not only to protect ships crossing from the United States to Europe or to the Mediterranean Sea and North Africa, and the island ports, but also to protect the Azores’ important coal and fuel deposits, telegraph cable hubs and wireless stations, a German prisoner-of-war camp, and the population itself.17 The Portuguese military tried to match the number of weapons to the number of recruits that were incorporated.

The U.S. Navy collier USS Orion (AC 11) had arrived in Ponta Delgada on 18 June 1917 to establish a charcoal depot for refuelling. The United States entered World War I on 6 April 1917, and after the German attack on Ponta Delgada, the Azores occupied part of America’s attention in the Atlantic, as well as the Portuguese government’s. Thanks to the impression of security generated by Orion and the Portuguese artillery’s defense during the German attack on Ponta Delgada, the population welcomed the Allies and helped them to build the U.S. facilities. This response created an atmosphere for trade and a lasting friendship that remains today.18


Naval Battle between USS Orion and U-155, 4 July 1917

The Azores had two advantageous harbors in Horta and Ponta Delgada that refueled the warring countries, and islands like São Miguel were topographically known by the German Navy.19 After the first attack on Funchal, prevention and observation of the sea became essential while waiting for the Portuguese state to promote the defense of the Azores. The feared attack occurred on 4 July 1917 at about 0500. The city awoke at dawn to a bombardment by German U-boat SM U-155’s 105mm grenades under the direction of Captain Lieutenant Karl Meusel. A telegram informed the minister of war, Colonel Eduardo Agostinho Pereira, military commander of Ponta Delgada, that a large enemy submarine was bombarding land repeatedly and intermittently, reaching up to approximately 4 kilometers (km) from the coast.20 The civil governor of Ponta Delgada, Ricardo Salgado, informed the minister of the interior that “a submarine appeared in front of this port. The American transport ship at anchor is attacking an enemy along with a land battery.”21 The naval artillery caused damage in two rural settlements, resulting in one death and injuring four people. The Portuguese battery recently installed at Mãe de Deus hill and the USS Orion, in maintenance in the port of the city, responded to the enemy’s fire.22

U-155 attacked southwest of the city, opening fire with eight shots to which the Orion responded with 15 100mm shots and the Portuguese battery Armstrong (10/28) with four 100mm shots. The rapidity of the American response was possible because the telegraph operator of the Portuguese wireless in nearby Nordela, in their usual scan for new communication records with ships, detected the approaching German submarine. Given the radio alert, the Orion, guided by Lieutenant Commander John H. Boesch, responded by raising the alert level and returning the German fire shortly after the first shots.23


CAC3200, Coleção Museu Carlos Machado House hit by the U-155 bombing, 4 July 1917.





CAC3208, Coleção Museu Carlos Machado
USS Orion and Friant steamships at Ponta Delgada dock, São Miguel, 12 June 1917.


After the intense exchange of fire, U-155 retreated to a safe zone, keeping within range to possibly renew the attack. Meanwhile, Captain Lieutenant Meusel interrogated the crew of a coastal vessel, trying to get more information about the unknown American ship in the port. Salgado informed the minister of the interior and his counterparts in Horta and Angra do Heroísmo (on Terceira Island) that the Portuguese artillery had been insufficient to protect the city, which left to Orion the victory of repelling the enemy. The concept behind the positioning of the Portuguese 100mm coastal artillery battery in Mãe de Deus hill could have worked, if—as it had in Funchal—the submarine headed for the bay of the port; but it did not. The obsolete Armstrong’s artillery was no match for U-155. The German submarine, with around 20 crew members, was spotted heading south in the late morning.24 However, it was expected to return, so the Portuguese infantry was positioned along the city coast, preventing the population from leaving or entering the city. The Portuguese artillery was ordered to combine its fires with Orion’s, using red flags during the day and flares at night. Meanwhile, the west wing of the city (Santa Clara) was reinforced with three 70mm artillery cannons (obsolete) with orders to wait until the last minute to fire. National and foreign forces were in high alert and civil society paralyzed, even at night with public lights extinguished. In the following days, the military believed that U-155 was responsible for several torpedo attacks in the Azorean sea. The submarine positioned itself between the two Portuguese archipelagos and Gibraltar, returning at the end of the month and remaining in activity until 7 August. 

On 8 July, by way of the American consul, the island’s authorities saluted the crew of Orion, and a very friendly atmosphere for the American presence emerged in the city. In the subsequent months, the name Orion would be attributed to breweries, cigarettes, cookies, and even to children. The mayor of Ponta Delgada offered Lieutenant Commander Boesch a silver cup, and several years later the U.S. Navy unit, officers, and crew were distinguished by the Portuguese Republic with the government decoration Torre e Espada (the Military Order of the Tower and the Sword).25 Later, in the Portuguese Parliament, some deputies presented the proposal that the city of Ponta Delgada receive the War Cross, generating a debate that was quickly abandoned until the present day.26

The attack and subsequent German predations by U-155 exposed the lack of surveillance and control of that part of the Atlantic, traditionally associated with the Portuguese Navy, which at the time lacked modern ships, or with Britain, which withdrew farther north after the Jutland battle. Following military recommendations, the civil governor prohibited all public events and popular gatherings, even requiring citizens to stay away from windows. Gunpowder storage was removed from the city and fishermen were kept from their work, generating complaints that were reinforced in the media, which condemned the Portuguese First Republic. 

The Orion left Ponta Delgada a little more than one week after the German attack. The American presence was conditioned by Portuguese bureaucracy to access to its own coal deposits and Portuguese law limited the supply to ships that did not carry out of the port, and the delay could have serious consequences for the assembly of the American facilities in Ponta Delgada. During the week of 21 July, eight steam ships were sunk by a U-boat off Santa Maria, some by U-155, causing a new flow of castaways.27 In the following week, the newspaper Açoriano Oriental announced the arrival of the American destroyers that formed the U.S. Navy’s division in the Azores. Its mission was to cover the maritime area of the Azores, preventing enemy access and assuring help to shipwrecked or otherwise distressed vessels. In the same week, some media reported that for the Germans, the islands were important logistically to dominating the North Atlantic.28

From this date on, shipwrecks along the coast, especially of American ships, became common. In early August 1917, the American consul asked the civil governor of Ponta Delgada for a numerical list of the officers and crews landed on Santa Maria to “be able to appreciate the accounts sent by the administrator of Vila do Porto municipality with the costs of hosting Americans, as well as the duration of stay.”29 Across the archipelago, the fear of a new attack was permanent, a result of the bombings of Ponta Delgada and Funchal and the growing number of German submarines spotted. On 7 August 1917, the military commander of Horta warned the military commander of the Azores of the presence of U-boats and a probable refueled ship near Fayal and Pico Islands and requested the defense of those two islands and of Flores and Corvo. The four islands’ mayors were insistent on behalf of the people. The Portuguese Army and Navy had to reinforce defenses in all the nine islands, but the Portuguese Republic was unable to provide the resources to do it. Despite few means and multiple conflicting demands, the military command of the Azores created detachments in the nine islands, largely symbolic, and the future American sea patrols helped to transmit security to all of the Azorean population.

Coincident to the establishment of the U.S. Navy facilities at Ponta Delgada, citizens reported unidentified submersibles around the islands. In January 1918, they were spotted near São Miguel, for example, and sometimes artillery shelling was heard. Materials and shipwrecks from different nations proved that not all the sighted vessels were American, causing problems among shore-bound sailors of different nationalities. Patrolling cruisers, destroyers, and submarines conducted reconnaissance between islands, Madeira and probably Canarias, followed by seaplanes along São Miguel’s and Santa Maria’s coasts in a clear demonstration of the capacity of the American patrols, but without any success. 

The German Navy attacked isolated ships, but there was no further confrontation between the German and U.S. navies, frustrating the U.S. Marines operating out of Ponta Delgada, despite all American naval maneuvers. For example, SM U-139 (1917) attacked two Portuguese steam ships on 14 October 1918.30 The first one, the steamer Sãn Miguel, was a civilian transport and the second, the NRP Augusto de Castilho (1915), its escort. After a two-hour fight, the Sãn Miguel achieved security with the NRP Ibo (1911), and by the time the U.S. Navy vessels reached the contact point, the Augusto de Castilho had been sunk and part of the crew lost.31


The U.S. Detachment and the High Commissioner of the Republic for the Azores

Meanwhile, fear and rumors characterized Azorean society. After the second attack on Funchal on 12 December 1917, the population were discouraged and goods were in scarce supply. The development of total submarine warfare discouraged the Azorean and Portuguese merchants from risking imports and exports, stopping regular trade between the archipelago and the mainland and generating a situation that was aggravated by governmental insensitivity to the specific needs of the islands for products, such as matches.32 The economy was stagnant without imports, markets, ships, or alternatives, which were suffering from heavy war costs on the few existing transports. The shortages created by the lack of importation led to the hoarding of goods such as eggs, chickens, and lobsters and even put pressure on clandestine trade, resulting in commercial stagnancy or attempts to inflate prices even more. In addition to hunger and war, an influenza pandemic occurred in 1918, aggravating the social and political instability that characterized the First Portuguese Republic.33

In this context, the presence of a U.S. naval base was welcomed and the creation of a Portuguese High Commission of the Republic for the Azores in 1918 represented an effective solution to coordinate the joint effort between national and foreign, military and civilians.34 The First Republic would try to match this, even if symbolically, by sending more (obsolete) artillery materiel and attempting, without practical and concrete results, the establishment of an airborne unit in Horta, with a detachment in Ponta Delgada, or even the first aerodrome in Terceira Island.

With the evolution of the conflict, the crisis would generate economic or ethical disruptions for administrative authorities. With an agricultural calendar linked to climate conditions and with the worsening of transportation, in 1918 wheat was requisitioned parish by parish, provoking popular riots and military intervention that, without mechanized support, could take many days to reach multiple destinations. Supported by the American allies and with the high commissioner of the republic already in Ponta Delgada, the situation would change. The U.S. Marine Corps were always available to assist on land or at sea, namely in connection with the United States or in the interisland supply of foodstuffs.


The American Naval Base 13 in Ponta Delgada and the Portuguese Powers, 1917–19

With the establishment of the Americans on our island, navigation of the Atlantic Ocean was guaranteed against enemy invaders and protected from espionage; this complemented the naval strategy of the Allies with actions along the coast on the continent.35


This was the Azorean feeling when the American naval base was established during the summer of 1917, after the attack on Ponta Delgada. Many locals hoped that a permanent base would defend the coastline and protect small, isolated ships and supplies intended to support the war effort. It was a critical year for the outcome of the war. Germany had less strength on the western front, but seemed willing to gamble with submarine warfare tactics, believing that it could win control of the North Atlantic Ocean, over England, even if that meant the entrance of the United States into the conflict.36 The risk of an unrestricted submarine warfare campaign had detrimental effects on a large zone of the Atlantic and caused America to enter the war in April that year.37 The seas surrounding the Azores were no longer on the periphery of the operations, rather they had become an important arena for the destruction of Allied ships, specifically in the triangle between the Azores, Europe, and Africa, and a refueling point for submarines.38 In this context, the Azorean sea became one of the principal American preoccupations in the defense of its own coasts and transport of reinforcements, but was also of interest to the British to control access to their own harbors.39

The German attack on 4 July confirmed the American theory regarding German interest in the Azores. By the end of July 1917, the American naval transport USS Panther (1889, later AD 6) and five old steam-powered destroyers arrived in Ponta Delgada.40 This group would be later designated as Destroyer Division One and went on to form the core of U.S. Naval Base 13, Azores, but without official status.41 The Azores became an intermediary point for small ships crossing the ocean from the United States, whether on their way to France or for vessel recovery. The mission of Destroyer Division One was to cover the general area of the Azores, to impede enemy action, and to assist shipwrecks and sea rescue missions. By the end of August 1917, the division was ordered to advance to France and was relieved by a new force, which included the monitor tender USS Tonopah (M 8), three destroyers, and a submarine division.42 This force also could extend to the neighboring archipelago of Madeira, southwest of Portugal, and almost to the Canary Islands of the northwest coast of Africa.













CAC3252, Coleção Museu Carlos Machado
Curtiss R-6 planes at Flying Beach in Ponta Delgada, São Miguel, 7 March 1918.


About three weeks after the Ponta Delgada attack and during a period of strong German submarine action in the Azorean sea, the local media announced the presence of five American destroyers, two of which had already stopped in Ponta Delgada and one in Santa Maria, the neighboring island, for rescue missions.43 The following week, various conflicts broke out between the locals and the Americans, which scared the peaceful population of the city. A shooting left people injured and a melee was stopped only by firing a round of dry gunpowder artillery. After these episodes, the authorities began to reinforce military discipline.

On 25 August 1917, Colonel António Germano Serrão dos Reis, the military commander of Ponta Delgada, sent a telegram to the military commander of the Azores in Terceira, Colonel António Veríssimo de Sousa, which announced the presence of Americans in the harbor.44 The Portuguese Navy commander began a series of visits to the American warships to determine their intent. The American presence on the island had become a cause of concern for the Portuguese authorities because of the lack of official authorization. To remedy this and to provide better conditions for the troops, the American government officially requested that Portugal allow a Navy base within Ponta Delgada, which would provide a better defense of the harbor and the city.45 Portugal approved the action on 8 November 1917 and the chief of U.S. naval operations, Admiral William S. Benson, appointed Rear Admiral Herbert O. Dunn as commander of this newly approved American base in the Azores.46 The U.S. Navy also ordered sufficient U.S. Marines and seaplanes to defend the coast, to patrol the Azorean seas, and to protect the harbor.

By the end of November, supply posts had been established for the foreign vessels. The media denounced the situation as annoying, saying that the business of the island was stymied by the high taxes the customs office applied for those who had come to defend the island.47 By the end of September, Júlio Milheirais, Ponta Delgada’s naval port commander, had received the Portuguese Navy minister’s consent to authorize the American request to install gasoline in warehouses, guarded by the Portuguese Army. However, the Portuguese military commander also was preparing his transfer from Terceira to Ponta Delgada on 23 November 1917.48

By 25 November, the military commander of the Azores would concede all facilities to the U.S. Navy to improve the logistics of ships in transit.49 The Portuguese war minister authorized the placement of a U.S. Marine Corps aviation unit on the island. The U.S. naval contingent consisted of Admiral Dunn, 3 other officers, 90 sailors who would patrol the seas in the region, and 50 sailors to guard existing warehouses on land. Above all, the minister of war gave instructions to all Portuguese authorities to avoid delays in the American initiatives. However, the authorization was only for their presence on Ponta Delgada and did not allow similar concessions on the other islands without Portuguese government permission.50

By mid-December 1917, intense American naval activity dominated the area. On 16 December, the commander of the U.S. Navy Detachment, Azores, Lieutenant Commander Hugo W. Osterhaus, requested that the military commander of the Azores and the captain of the Ponta Delgada port advise the population about the military activities around the harbor.51

Rear Admiral Dunn arrived in Ponta Delgada on 9 January 1918 with a force of 150 riflemen, 10 seaplanes, two land cannons to defend the port and the new British wireless telegraph station, a division of submarines, a small number of coastal patrol boats, some logistical ships, one or two naval transports, and one or two destroyers, both on a temporary basis.52 At the core of these diplomatic events, both international and local, the president of the First Portuguese Republic (and war minister), Sidónio Pais, wanted to balance the different foreign influences in Ponta Delgada.53 Though he had accepted the Americans’ presence, he did not trust them. Some of these pressures were felt locally, as society was divided among those favoring the Americans, the British, or the Germans. In this volatile context, with a foreign force commanded by an official general within its national territory, the solution implemented was to create a new military position, above the pro-German Portuguese high navy commander, Admiral Augusto E. Neuparth. This new post of high commissioner of the Republic for the Azores centralized all military and civilian functions by someone receptive to the Allies, especially the British. General Simas Machado, the former commander of the 2d Division of the Portuguese Expeditionary Forces in the north of France, was selected.54

The impact of the American presence in São Miguel strengthened during January 1918. On 4 January, President and Minister of War Pais gave orders to the military commander of the Azores, Colonel de Sousa, to cooperate with Rear Admiral Dunn in matters of defense—always safeguarding the independence of the military commander of the Azores—and to assist the Portuguese Navy in tactical matters.55 In this phase, the American forces were not allowed to disembark. However, they could use supplies, upon request.

Preparations for the disembarkation of the American forces soon began. On 17 January, they began working on the installation of two barracks on the grounds around São Bras Fortress, next to the harbor. On 21 January, the Americans obtained the authorization to come ashore. The local authorities and the American consulate spoke with Rear Admiral Dunn to prepare for their arrival the next day. On 24 January, the American consul questioned the possibility of constructing repair facilities by the guard houses of Corpo Santo beach, along the eastern walls of the São Bras fortress. On 27 January, the public disembarkation of the USS Hancock (1879, later AP 3) began with official military honours. Dunn and his staff arrived first, followed by the Marine aviation corps and a guard of 50 armed and equipped Marines. Dunn was visited by Colonel de Sousa, who informed him of the Portuguese concessions. In response, the admiral informed de Sousa that he had brought two of the latest 7-inch seacoast guns to defend the harbor and the British telegraph station in Feteiras, a small town located a few kilometers from Ponta Delgada.56

The authorized forces unloaded a significant amount of materials through 31 January. The goods, including grenades, airplane engines, sacks of cement to make platforms for the artillery, material for airplane repair, two trucks, two cars, and a large quantity of food were placed in warehouses around the city. Separately, more than 4,410 pounds of gunpowder were placed in small bags in the Ponta Delgada army storage room. The rest of the materials for the aviation company were unloaded in the Pedreira da Doca, an area less than 1 km west of the fort. The other explosives were unloaded at the fort and later moved to the newly constructed bunkers on the Serra Gorda mountain about 7 km from Ponta Delgada under the guard of a small detachment of the Portuguese 26th Infantry Regiment.

Meanwhile, construction continued around the fort, as the ancient boat ramp area of the beach was transformed into a concrete ramp to create facilities to repair the planes and the submarines, as well as lodgings for the submarine garrisons. Initially, there had been some confusion among the local, national, and American authorities due to the use of military areas; but this time, the work was carried out within the framework of mutual understanding between the American and Portuguese commands, while maintaining Portuguese national sovereignty and prudent diplomacy.

Meanwhile, Rear Admiral Dunn approached the Portuguese authorities with offers of extra manpower and equipment. On 2 February 1918, a meeting was held in de Sousa’s office regarding the placement of the two cannons, which was attended by a Portuguese Army lieutenant colonel engineer and major, an American lieutenant, and a British officer.57 One cannon was intended to defend the harbour of Ponta Delgada and the other to defend the new British telegraph station. The admiral would furnish two 45–caliber, 7-inch rapid fire guns, as well as the labor and materials for construction of their respective concrete platforms. The Portuguese officers offered to help with the construction, but it was declined.58

Before Dunn agreed to move ahead, he wanted to review the selected locations. The leaders first considered the British telegraph station at the base of the hill of Vigário. The admiral chose a southern position by the sea on a 650-foot-tall cliff, but in a depression. The Portuguese had hoped that this cannon would not only protect the station but also Ponta Delgada and the harbor; however, this was not the admiral’s intention.

Dunn also was shown a location in Santa Clara, just on the western outskirts of the city center, where codfish was normally dried. A cannon in this position could protect the western half of the city. Both choices were accepted by the Portuguese commission with reticence: if the cannon in Feteiras had been placed a little more to one side, it would have better protected the city, but Dunn would not budge. The cannon in Santa Clara was to be installed between a recently constructed battery of two Portuguese AE 150mm P (MK) cannons.59 The Portuguese engineer agreed to do this, knowing that the American cannon was of higher caliber and rapid fire, which would be fundamental in defense of the island against attack.

The cannons were placed in position as quickly as possible. The authorization for the implementation of the telegraph station defenses in Feteiras was approved on 1 March 1918. One cannon would protect the British telegraph station and the other in Santa Clara would protect the city port.60


1st Marine Aeronautic Company in the Azores

The activities of the Corps’ 1st Marine Aeronautic Company in the Azores are not widely known, but some studies may help to understand the framework and mission in the Azores. By examining historians António Godinho’s and Hugo Cabral’s research, it is possible to gain some insights into the dynamics and results of the 1st Marine Aeronautic Company.61 Marine Corps aviator Walter Smith Poague’s diary entries from October 1918 form the basis of Godinho’s work. Poague started writing on 6 April 1917, when Marine Aviation was an experimental unit—Marine Aeronautic Company—with only 7 officer aviators and 43 enlisted Marines. It was just a section of Naval Aviation, operating with four Curtiss AH hydro-aeroplanes. After his enlistment, Poague trained at Marine Corps Base Quantico, Virginia, where he was later commissioned as a second lieutenant.62 Basic flight training lasted 10 weeks.

Lieutenant Poague was sent to Cape May, New Jersey, in October 1917 and stationed at the Aviation Department Flying Field. On 12 October, Marine Aeronautic Company was split into the 1st Aviation Squadron (24 officers and 237 enlisted Marines) and the 1st Marine Aeronautic Company (10 officers and 93 enlisted Marines). On 14 October, 1st Aeronautic Company was transferred to Cape May, where it was equipped with two Curtiss R-6 floatplanes with the mission to carry out antisubmarine patrol duty along the coast.63 Lieutenant Poague was assigned to this unit, which was commanded by Captain Francis T. Evans, a skilled pilot who was the first to successfully execute a loop with a Curtiss N-9 seaplane in 1917. The spin-recovery maneuver of the loop became a basic element of aviation safety and earned Evans (retroactively) a Distinguished Flying Cross in 1936. Second in command was Captain David L. S. Brewster; the other officers included First Lieutenant Harvey B. Mims and seven other second lieutenants, including Poague.

CAC3252, Coleção Museu Carlos Machado
Curtiss R-6 planes at Flying Beach in Ponta Delgada, São Miguel, 7 March 1918.


In December 1917, 1st Marine Aeronautic Company received orders to depart for Naval Base 13 at Ponta Delgada. Its mission was antisubmarine patrols, using 2 Curtiss N-9 and 8–10 R-6 seaplanes.64 On 9 January 1918, the Hancock left Philadelphia carrying the 1st Marine Aeronautic Company with 13 officers and 122 sergeants and enlisted. Poague and his fellow Marines were transported to the archipelago by the Hancock, an 8,500-ton transport ship.65 Under Evans’s command, after a stormy trip and stop at Horta to refuel, the Hancock and its escorts arrived in Ponta Delgada on 23 January. The unit was placed under the command of Rear Admiral Dunn, who reported to Vice Admiral William S. Sims, chief of naval operations in Europe. After three weeks and up to May 1918, the company began an operational career related to the qualification of pilots. When the aeronautical company arrived in the Azores, only 3 pilots had their wings; the 10 others earned them in the theater of operations.66 In May, having made their first solos, these untrained pilots were conducting patrols offshore, and by the beginning of June they had their final tests as naval aviators.

According to Poague’s diary, after the initial flights, an intense instruction period started for the seven second lieutenants, from flight practice in their new environment to operational aspects of their flying. They were the backbone of the unit’s operation. The weather was the main obstacle for the Marine aviators, learning how to operate in the seas and winds around the Azores.

By the end of July 1918, the submarine menace was considered under control by the chief of naval operations, and at this time the 1st Marine Aviation Squadron arrived in Brest, France. Only Squadron D remained in Miami, Florida. With almost all of Marine Aviation deployed overseas, skilled pilots were needed to continue building and sustaining the major unit and several were transferred back to the United States, including Captain Evans (with a total of 4.3 scouting flight hours), First Lieutenant Mims (3.8 hours); Second Lieutenants Hill (22.1 hours), Sellon (29.5 hours), and Boyton (1.0 hour); and Gunnery Sergeant Carl Ehlers, who also logged only one scout flight.67 At the officers school, the admittance terms where changed, giving priority to the personnel who were in the ranks.

The reduction of the number of pilots did not affect the number of scouting flights. The first patrol was carried out on 12 April and then whenever the weather permitted. At least two patrols were performed daily: one at sunrise and one at sunset. However, there were also days when four or five patrols were made. The duration of these flights gradually increased. Until the end of April, they were approximately 30 minutes. In May, they lengthened to an hour, and from there the length of patrols stabilized to an average duration of one and a half hours. Poague reported that flights were made off Ponta Delgada up to a distance of 25 km and with the island in sight. Without radio aid or wireless, and sometimes not even a compass, patrols occasionally went wrong when planes ran out of gas (the planes did not have fuel gauges) or got lost in the fog that usually covers the island of São Miguel. In July 1918, the flights totalled 104, of which 82 were for scouting (78.9 hours). The small decrease of flights, compared to the previous month, could be justified by four days of bad weather. In a month with good weather, the total scouting hours were around 80 hours—the maximum that they could sustain. However, keeping up with this operational tempo resulted in an increase of accidents due to materiel fatigue.68

After a short time, the Marines noted that the Azores were not often harassed by U-boats, so it seemed unnecessary to keep such a large military presence there. In July 1918, 1st Marine Aeronautic Company was reduced to 6 officers and 75 sergeants and enlisted, almost half of the original personnel. Captain Brewster commanded the company from 21 July.

On 2 September, three new Curtiss HS-2L flying boat patrol planes arrived to replace the dated R-6s and N-9s. The new aircraft had much more potential and durability for operations in Azorian waters.69 Unfortunately, engines were not loaded on the ship, a situation resolved later. Although the daily reports are not clear, it seems that the flying boats only started to operate at the beginning of October, but there is no doubt that the old R-6s operated until the end, as there are many records of aerial and maintenance activity of these planes. During the 1918 influenza pandemic, 1st Marine Aeronautic Company lost four pilots, so October represents a drastic drop in patrols as a result of the lack of both personnel and good weather. On 1 November, there were only nine pilots in the hospital and the company attempted a return to normal activity.70

Despite the quality of Glenn Curtiss’s engines and seaplanes, like any other air unit, 1st Marine Aeronautic Company had accidents. The seaplanes eventually became too fragile to operate under the sea conditions around Ponta Delgada; waves were a constant in the artificial port, battering the seaplanes. In addition, the port was constantly crowded with ships, boats, and buoys, obstacles that sometimes became visible to pilots too late to avoid. The first accident occurred as early as 15 March, when Second Lieutenant Mims’s plane (A-208, a Curtiss N-9) ran out of fuel just outside the harbor. Although it was towed, the cable gave way and the aircraft drifted until it was destroyed against the rocks on the coast.71

Similarly, plane A-334 (a Curtiss R-6) crashed 13 km from Ponta Delgada on 19 June. The pilot, Gunnery Sergeant Ehlers, only had a few abrasions, but the plane sank to the bottom. On 9 October, First Lieutenant Poague’s A-328 (a Curtiss R-6) lost power shortly after taking off and Poague maneuvered to avoid a metal buoy. As his Curtiss R-6 skidded, the wings and the floats broke. Poague and Gunnery Sergeant Walton B. Ziegler (the mechanic) had to swim and wait for assistance, but the aircraft was recovered. On 10 October, plane A-337 (a Curtiss R-6) had a power failure, forcing First Lieutenant William Embry to make an emergency landing in rough seas. The masts of the left float gave way and the propeller cut the tips of the floats, which caused the hydroplane to half-sink with its nose submerged. The crew suffered no injuries, but the plane’s wings broke during its recovery and the aircraft was considered unrecoverable.72

However, the most dramatic accident occurred on 5 November, less than a week before the Armistice. At 0600, Poague and Ziegler boarded the A-335 (a Curtiss R-6) for the first patrol of the day. The aircraft overturned on take-off in Ponta Delgada bay, and Ziegler, while working to free himself, could not save Poague. Poague’s remains were transported back to the United States by the cruiser USS Chicago (1885, later CA 14) on 21 November 1918 and he was buried in Oak Woods Cemetery in Chicago on 21 December 1918.73

During nine months of operations in the Azores, 1st Marine Aeronautic Company lost one aviator and five planes in accidents, in addition to numerous incidents that were not recorded.74 These figures may seem daunting by current standards, but considering the intense aerial activity, the fragility of the planes, and the operating conditions, and comparing it with other contemporary units, it seems that 1st Marine Aeronautic Company was very lucky.

Poague and Ziegler’s 5 November flight was the company’s last patrol attempt. As of 11 November, a large part of the company’s activity was limited to packing its materiel. Interestingly, the only air activity after Poague’s accident was the assembly of and three test flights on the Curtiss HS-2L (belonging to the Portuguese) with plane A-1362, which according to Major Brewster’s reports was assembled on 7 November. It is important to clarify that this Portuguese HS-2L did not belong to 1st Marine Aeronautic Company. Portuguese Navy archive documents confirm the purchase of four American seaplanes to equip the Horta Maritime Aviation Center in June 1918.75 However, after the Armistice, the Americans proposed that the Azorean authorities buy three or four seaplanes, a motorboat, and various machinery from 1st Marine Aeronautic Company for approximately 48,000 escudos ($525US 2021). First Lieutenant Adolfo Trindade, responsible for the Horta Portuguese Navy Center, was required to carry out the purchase, but due to the bureaucracy and anarchy of the time, the first response from Lisbon arrived too late: the ship carrying the seaplanes had already set sail for America five hours earlier.

The company detached from the Azores on 24 January 1919, arriving at the Marine Flying Field in Miami on 19 March, probably the last day of 1st Marine Aeronautic Company’s existence. The flying beach and its Ponta Delgada facilities were used by the Portuguese to install the Azores Maritime Aviation Center, which was closed two years later without experiencing the air activity of its predecessors.


CAC3230, Coleção Museu Carlos Machado
Flying Beach in Ponta Delgada, São Miguel, 9 February 1918.







CAC3231, Coleção Museu Carlos Machado
Infantry sentry at Flying Beach in Ponta Delgada, São Miguel, 14 February 1918.


Photo by Raymond D. Borden, courtesy of Naval History and Heritage Command
The Flying Beach, 1st U.S. Marine Aeronautic Company, Ponta Delgada Harbor, U.S. Naval Base, Azores. 1918.


Naval Base 13’s Social Effects and Demobilization

During his command of the U.S. facilities in Ponta Delgada, Rear Admiral Dunn introduced himself to the social life of the island in February 1918 by helping the poor. He was even given a welcoming party at the Teatro Micaelense with the local VIPs and the British telegraph commission.76

Economic development rapidly expanded, even in February, as verified by the fact that new hotels appeared and the local press referred to the period as an opportunity for financial gain.77 The annual Mardi Gras celebration was limited because of the war, but included a “battle” of flowers to honor the visitors. The following month, festivals were announced to raise funds for the Portuguese Red Cross and films—made during training exercises as seaplanes flew over Ponta Delgada—were exhibited to show the southern coast of the island. New restaurants were opening and even the popular language was affected by the American presence. For example, one of the most important restaurants in the city was named the Washington. On 11 March, the Azores detachment of the U.S. Atlantic Fleet invited the military commander of the Azores to assist in the cannon test in Santa Clara.78 And on 28 March, exercises took place southeast of the village of Povoação, with the gunboat USS Wheeling (1897, later PG 14) and an American patrol boat. In April, there were festivities at the naval club of Ponta Delgada, with friendly competitions between American and Portuguese sailors.

At this time, the American ships helped the local businesses by providing necessary supplies from the United States, such as malt for the beer factory, which in turn would provide ice for the hospital.79 The admiral was greatly admired for his good works in Ponta Delgada, such as the soup kitchen for the local poor and theatrical productions to benefit the Red Cross. On 3 July 1918, seven days after the Portuguese Red Cross delegation opened in Ponta Delgada, its president, Luís de Bettencourt de Medeiros e Câmara, thanked the admiral for sending a donation of 890 escudos ($10US), the largest contribution at that time.80 Rear Admiral Dunn’s efforts reinforced the good image of the base and provided a vehicle for economic development in the region, surpassing the local patrons of good works.81 This image was reinforced during the influenza pandemic that autumn, when he offered his assistance and the support of the American Red Cross to the island. Upon his death many years later, the local newspaper, Correio dos Açores, reported the admiral’s demise in terms of a person who had greatly helped the population as a benefactor to the poor. He had worked to deliver grain to the various islands, imported American flour, and given gasoline to the local authorities so doctors could provide medical care during the pandemic. He had even sent a destroyer to Gibraltar to obtain medicine. Dunn was considered one of the principals responsible for keeping the death rate from influenza below 2,000 people in São Miguel.82

Despite Dunn’s efforts to convince Vice Admiral Sims of the importance of maintaining the American naval base in Ponta Delgada, demobilization began on 20 January 1919 with the embarkation of most of the Marines and planes on the USS Nereus (AC 10).83 However, minimal services were maintained on the island until September 1919 to support the small ships that were returning to the United States after the war. In March 1919, the Americans gave the Portuguese the two mounted 175mm cannons, as well as two 75mm cannons and some crated seaplanes. On 14 April, Dunn transferred the command to Rear Admiral Richard H. Jackson and returned to the United States.84

With the war over and new technology in place, the first transatlantic aviation crossing was successfully completed. On 19 May 1919, Navy lieutenant commander Albert C. Read and his crew arrived in the Azores in their Curtiss NC-4 flying boat from Newfoundland, Canada. Three planes attempted the crossing, but only one was successful. With the help of the Ponta Delgada naval base for refueling, the plane reached Lisbon in 27 hours.85

On 23 August 1919, Rear Admiral Jackson announced his plan to leave and to demobilize the base. He gave orders to dismantle the American hospital and to give the barracks to the Portuguese. With the Americans’ departure during the week of 20 August, Naval Base 13 was officially closed.86 The base was quickly disassembled. It had only ever been considered temporary protection for the coal supplies in the harbors and the Azorean seas from the Triple Alliance. 


Final Considerations

The final demobilization of Naval Base 13 on Ponta Delgada began in March 1919 with the order to withdraw defense vessels, reducing the mission of the detachment to support of small escorts returning to the United States. Admiral Dunn delivered the artillery and some materiel to the Portuguese authorities and departed on 14 April 1919. The departure of the last Marines took place the week of 20 August 1919.

The rapid demobilization of American forces was a reflection of how the United States always viewed the Azores Detachment of the U.S. Atlantic Fleet in Ponta Delgada: temporary. Its existence represented security to the population of São Miguel and generated confidence in the rest of the archipelago, especially in the nearest islands, and also for isolated ships crossing the sea between Bermuda and Gibraltar.87 The details of the base’s operability are not well known, however it was not very intense. Naval Base 13 was involved in regular exercises and sea and air patrols in the area between the Azorean sea (almost to the Bermuda Sea), Madeira, Lisbon, Gibraltar, and nearly to the Canarias sea, and that the most dangerous moment could have been contact with a possible U-boat that submerged, wreaking confusion among the Marine aviators on 11 September 1918.88 But the mission was, in part, accomplished: access to the Azores was denied to the enemy and the Azorean sea was secure. The main route between the United States and southern Europe, passing by Bermuda and the Azores, especially for nonconvoy ships, was more secure, and ships could be sure of secured harbors for refueling and repairs. With the support of the U.S. radio facilities in Ponta Delgada, Dunn could prepare their passage, escorting them if necessary.89

The legacy of the United States’ presence in the Azores, however, would remain in the collective memory for the help in preserving public order, goods, and free transportation to and from the United States, as well as for the dynamism of trade and technology. The existence of an Allied admiral led to a response from the Portuguese state by naming an officer with a rank equivalent to that of a U.S. Navy rear admiral and in the face of possible diplomatic instability, a pro-Allied leadership with vast civil, military, and diplomatic powers. Like the American presence, the transition from the military command of the Azores from Terceira to São Miguel between December 1917 and 1918 would be provisional—but indispensable—in representing the Portuguese government until a provisional high commissioner of the republic arrived in the region.

The American military presence extended to helping the local population, including providing support during the influenza epidemic. Internally, far from enemy action, the island and its American naval hospital provided a valuable resource as a secure refuge for all that crossed the Atlantic, providing medical care or assistance in death, at an important halfway point of the route. The American military base in the Azores provided logistical support, doctors, and administrative services, which were primary concerns. This was important for all 38 cases of death, and perhaps more importantly, for all those who survived because of these resources.

Although the U.S. Marines in the Azores did not see as much action as their aviator comrades who served in France, they provide the best demonstration of the Marine Corps’ ability to quickly mobilize an aviation unit and keep it on expeditionary service for a long period of time. This unit’s activities can be said to have contributed to the maintenance of a modest aerial component in the Corps until the Second World War. While monotonous, the 1st Marine Aeronautic Company’s service was not free of danger, as the few injuries and deaths show.90 The reduction of the company’s personnel is probably attributable to the lack of results and flexibility and use of materiel, as well as the fact that only half the planes shipped were used; many were cannibalized for spare parts.

Resilience and adaptability are two important characteristics of those who stayed in the Azores working on new solutions or producing developments like the first scouting flight in the Azores (16 February 1918) and air-to-ground transmission in that region of the Atlantic, or even helping the Portuguese Navy to assemble the HS-2L plane that First Lieutenant Adolfo Trindade acquired from the United States for the Portuguese air center in the Azores (Centro de Aviação Marítimo dos Açores), as the counterpart of the U.S. Navy facility.91

Additional research may prove that the U.S. commands in the Azores and Europe remained open until planes gained sufficient ability to cross the Atlantic without stopping. The first transatlantic crossing completed in the Azores was not attempted simply to show off technological advancements but to advance commercial interests. Between the two world wars, Horta and Ponta Delgada continued to support naval and other pioneers of international aviation, including pilots from Portugal, Britain, the United States, France, Italy, and Poland. 

Indeed, the First World War was not the end of America’s presence in the Azores. The U.S. Air Force installed facilities on Santa Maria Island at the end of World War II, then moved to Terceira Island in 1946. Between 1939 and 1945, Portugal was again forced to defend the strategic importance of the Azorean sea, first as neutral then after supporting the Allies in the Azores.92 Both sides of the conflict saw in the islands the possibility of establishing harbors and airfields to support their military plans. The safeguarding of communications and the passage of sea convoys in the Atlantic as well as aerial cover of the routes were excellent reasons to invade the Azores, providing a starting point for the various belligerent expansionist projects, with or without the consent of the Portuguese state. 

Portugal’s fascist prime minister António de Oliveira Salazar declared the country’s neutrality in World War II, reinforcing the 1939 Iberian Pact with Spain and the military power in the three most important islands, preparing them to receive the government. Again isolated in the North Atlantic, the Azores suffered a new struggle for the domination of the seas. The interaction between civil and military authorities imposed by outside pressures shows the vulnerability of the Azorean people during World War II. The islands underwent serious difficulties to sustain the presence of a large Portuguese military contingent.93 With an economy that was dependent on others, the Azores was even more exposed to factors such as the economic blockade and the submarine warfare. The Azoreans again experienced many insecurities during the war due to both internal and external pressures, including lack of materials, food, and transport; inflation; reduced capacity for import and export, creating a black market; the drop in purchasing power; and the possibility of riots. Controlled by a fascist government with exceptional and authoritarian powers, the balance between the authorities, the military forces, and the Azoreans would work again, especially after 1943. To control the Azores Gap, the British (in 1943) and the Americans (in January 1944) requested use of the Portuguese government facilities in Terceira and Santa Maria Islands and support in São Miguel and Faial Islands.94 The establishment of permanent U.S. facilities in Santa Maria and the change to Terceira in 1946 prove that Rear Admiral Dunn’s view of the Azores’ strategic importance was correct and works until today.95

The Cold War reinforced the importance of the archipelago not only by the American facilities at Lajes Air Base (Air Base 4) on Terceira but also by the NATO harbor on São Miguel and a communications center on the same island.96 The visits by U.S. presidents to the archipelago, sometimes for international summits, are proof that even today the Azores are the first line of the U.S. Atlantic defense.97

On 8 February 1927, Rear Admiral Dunn appeared before the American Battle Monuments Commission (ABMC) to suggest the building of a modest memorial at Ponta Delgada “to commemorate the services of the American Navy in that vicinity during the World War. On the motion of Colonel Markey, it was decided that the Commission should erect a monument at Ponta Delgada.”98 The chairman of the ABMC, General John J. Pershing, requested authorization from the U.S. embassy in Lisbon to construct a monument to the memory of the World War I-era U.S. detachment in the Azores. The U.S. embassy forwarded the request to the Portuguese Foreign Affairs Ministry, which approved the plans and directed the Internal Affairs Ministry to collaborate with the ABMC and informed the local authorities. Unfortunately, while a design for the memorial was selected, the plan to build it was eliminated for economic reasons.99

Today, the process for a World War I memorial has been initiated again with the ABMC by the author and the U.S. consulate in Ponta Delgada, with the support of the U.S. embassy in Lisbon. It is the last effort to celebrate this common history after the 100th anniversary of the attack on Ponta Delgada and the first flight in the Azores.100 Both countries should work together to build this unique memorial to the U.S. Navy’s operations in the Iberian Peninsula during World War I. 



  1. The Azores are located between latitude 36º55’43’’ N and 39º43’02’’ N, and between longitude 24º46’15’’ W and 31º16’02’’ W. Ponta Delgada is on São Miguel Island, the major city of the Azores archipelago of Portugal. The Azores are nine islands divided into three widely separated island groups in the North Atlantic: the eastern group consists of São Miguel, Santa Maria, and the Formigas islets; the central group consists of Faial, Pico, São Jorge, Terceira, and Graciosa; and the northwestern group consists of Flores and Corvo. See “Units Composing, and the Commanding Generals of, the Second Division–Verdun Operations,” in Maj Edwin N. McClellan, The United States Marine Corps in the World War (Washington, DC: Historical Branch, G-3 Division, Headquarters Marine Corps, 1968; revised/reprinted by Marine Corps History Division in 2014), 38.
  2. RAdm Herbert O. Dunn letter to VAdm William S. Sims, 14 July 1918, World War I documents collection, Naval History and Heritage Command (NHHC), Washington, DC, accessed 5 October 2020; Joseph C. Sweeney, “Franklin Delano Roosevelt as Lord of the Admiralty 1913–1920,” Journal of Maritime Law & Commerce 48, no. 4 (October 2017): 442; and Luís Nuno Rodrigues, ed., Franklin Roosevelt and the Azores during the Two World Wars (Lisbon, Portugal: Fundação Luso-Americana para o Desenvolvimento, 2008).
  3. For more, see all entries for Portugal, 1914–1918, Online International Encyclopedia of the First World War (website), accessed 5 October 2020.
  4. João Carlos Moreira Tavares, “A defesa de Portugal durante a Grande Guerra. Doutrina e antecedentes históricos,” XIII Colóquio de História Militar: Portugal Militar. Da Regeneração à paz de Versalhes (Lisbon: Comissão Portuguesa de História Militar, 2003), 435–520.
  5. Nuno Severiano Teixeira, “Porque foi Portugal para a guerra: os objetivos nacionais e as estratégias políticas,” Portugal e a Grande Guerra, Nova História Militar de Portugal, vol. 4, dir. Nuno Severiano Teixeira and Manuel Themudo Barata (Rio de Mouro, Portugal: Circulo de Leitores, 2004), 14–34.
  6. António J. Telo, “Os começos do Século,” Nova História Militar de Portugal, vol. 4, dir. Nuno Severiano Teixeira and Manuel Themudo Barata (Rio de Mouro, Portugal: Círculo de Leitores, 2004).
  7. Entry for Herbert O. Dunn, [1857–1939], [RAdm 6.8.15], 22.11.15–4th Division, Atlantic Fleet, 1916–5th Division, Atlantic Fleet, 1917, Azores Detachment, Atlantic fleet, in Dr. Graham Watson, “World War I at Sea: Flag Officers of the United States Navy 1914–1918,”, accessed 5 October 2020.
  8. Josephus Daniels, Our Navy at War (Washington, DC: Pictorial Bureau, 1922), 276–78. The Azores had two excellent harbors: Horta at Faial Island and Ponta Delgada at São Miguel Island. While Horta is considered a better harbor in terms of winds, sea, and orientation, Ponta Delgada is larger and more populated.
  9. “U.S. Consulate Ponta Delgada,” U.S. Embassy and Consulate in Portugal (website), accessed 5 October 2020.
  10. José Vilela, Datas e Factos de Cabo Submarino em Portugal (1855–2015) (Lisbon: Fundação Portuguesa das Comunicações, 2016). The pioneers of the submarine cable and wireless telegraph communication centers in the archipelago are the British.
  11. Jorge Tavares da Silva and Rui Pereira, “China and the Portuguese Atlantic: The BRI’s Last Puzzle Piece,” in The Belt and Road Initiative: An Old Archetype of a New Development Model, eds. Francisco Jose B. S. Leandro and Paulo Afronso B. Duerte (Singapore: Palgrave MacMillan, 2020),
  12. José Medeiros Ferreira, Revisão Histórica da Participação de Portugal na Primeira Guerra Mundial–a Dimensão Ibérica Insular (Angra do Heroísmo, Portugal: Instituto Histórico da Ilha Terceira, 1987).
  13. John Brooks, The Battle of Jutland (Cambridge: Cambridge University Press, 2016),; and John Brooks, Dreadnought Gunnery and the Battle of Jutland: The Question of Fire Control (London: Routledge, 2005).
  14. Comando Militar dos Açores, Correspondência confidencial recebida. Pastas de notas, 1915, Centro de Documentação da Zona Militar dos Açores (CDZMA), FIA, 1092.
  15. Fortunato de Almeida, As Grandes Linhas da Política Externa Britânica do século XX—Evolução e Tendências, Ministério dos Negócios Estrangeiros, Lisboa, 1962.
  16. Dez Anos de Política Externa, vol. 4 (Lisbon, Portugal: Ministério dos Negócios Estrangeiros, 1973).
  17. Robert O. Work, Naval Transformation and the Littoral Combat Ship (Washington, DC: Center for Strategic and Budgetary Assessments, 2004); C. Valentim and P. Costa, coord., A Marinha Portuguesa na Grande Guerra: o afundamento do Caça-minas Roberto Ivens (Lisbon, Portugal: Comissão Cultural de Marinha, 2018); and Tad Fitch and Michael Poirier, Into the Danger Zone: Sea Crossings of the First World War (Cheltenham, UK: History Press, ebook, 2014). In early 1916, England’s lack of vessels led to Portugal confiscating German boats docked at its ports, instigating Germany’s declaration of war. This act would lead to the reformulation of German civilians’ status in Portugal, forcing those of military age to stay in prisons like São João Baptista in Angra do Heroísmo, Terceira. The prisons housed 715 prisoners of war, some with their families, by August 1918. Within the international war context, the Portuguese government sought to provide the best possible conditions, a complicated task due to the lack of medical support, food, water, and vaccinations. With the signing of the peace treaties, Portugal repatriated the remaining 596 ex-prisoners of war to Germany, after a short passage through Madeira and Lisbon. For more, see Sérgio Rezendes, Depósito de Concentrados alemães na ilha Terceira—A História de uma reclusão forçada (1916–1919) (Casal de Cambra, Portugal: Caleidoscópio, 2019).
  18. José Medeiros Ferreira, “Os Açores nas duas Guerras Mundiais,” Boletim do Instituto Histórico da ilha Terceira 45 (1987).
  19. Luís M. Vieira de Andrade, Os Açores e os Desafios da Política Internacional, Assembleia Legislativa Regional dos Açores, EGA, Ponta Delgada, 2002.
  20. Rodrigo Álvares Pereira, Esboço Histórico do Batalhão de Caçadores n.º 11 mais tarde Regimento de Infantaria n.º 26 (Ponta Delgada, Portugal: Artes Gráficas, 1927).
  21. Sérgio Rezendes, Ponta Delgada e a I Guerra Mundial—No centenário de todas as mudanças (Ponta Delgada, Azores: Câmara Municipal de Ponta Delgada, 2017), 156.
  22. “Class: Orion (Fleet Collier No. 11),”, accessed 6 October 2020.
  23. “Açores na Grande Guerra,” Açores 1914–18, Momentos de História, Projecto 100 (website), accessed 6 October 2020.
  24. Hans Joachim Koerver, German Submarine Warfare, 1914–1918: In the Eyes of British Intelligence (Berlin, Germany: Schaltungsdienst Lange, 2012). The U-155 was a 2,272-ton submarine with a crew of 56. “Type U 151: U-Cruisers and Merchant U-boats Class,” WWI U-Boat Types,, accessed 4 October 2020.
  25. “USS Orion (AC-11),” NavSource Online Service Ship Photo Archive, accessed 6 October 2020; and Entidades Estrangeiras Agraciadas Com Ordens Portuguesas, Ordens Honorificas Portuguesas, Presidência da República Portuguesa (website), 6 accessed October 2020. The Torre e Espada was bestowed on the Orion’s crew on 20 January 1922.
  26. Rezendes, Ponta Delgada e a I Guerra Mundial.
  27. U-155 activities in U-Boats and T-Boats, 1914–1918 (Washington, DC: National Archives and Records Service, 1984), 26.
  28. “A defesa da ilha,” Açoriano Oriental no. 4287 (July 1917): 14.
  29. Rezendes, Ponta Delgada e a I Guerra Mundial, 160.
  30. Walter S. Poague, Diary and Letters of a Marine Aviator (n.p.: Facsimile Publisher, 2016), 141.
  31. “NRP Augusto Castilho,” Associação Commandante Carvalho Araújo (website), accessed 29 May 2021.
  32. António José Telo and Augusto Salgado, A Grande Guerra no Atlântico Português, vol. 1 (Lisbon, Portugal: Fronteira do Caos Editores, 2018); Lawrence Sondhaus, Naval Warfare, 1815–1914 (London: Routledge, 2001); Jeremy Black, Naval Warfare: A Global History since 1860 (Lanham, MD: Rowman and Littlefield, 2017); Claude Delmas, Le Monde Atlantique (Paris: Presses Universitaires de France, 1958); and Karl Lautenschläger, Technology and the Evolution of Naval Warfare, 1851–2001 (Washington, DC: National Academy Press, 1984).
  33. Arthur J. Marder, From the Dreadnought to Scapa Flow: The Royal Navy in the Fisher Era, 1904–1919, vol. 3, Jutland and after (May 1916–December 1916) (London: Oxford University Press, 1978); and Ana P. Pires, Rita Nunes, and Sérgio Rezendes, eds. and coords., A Grande Guerra e os Açores—da Estratégia Naval à Pneumónica (Ponta Delgada: Letras Lavadas, 2019).
  34. Luís M. Vieira de Andrade, Uma Perspectiva Açoriana da Política Externa dos Estados Unidos da América e o Atlântico Norte (Ponta Delgada: Letras Lavadas, 2017); and J. M. Ferreira, “A importância do Porto de Ponta Delgada na I Guerra Mundial,” in Ponta Delgada—cinco séculos de concelho 1499–1999 (Ponta Delgada: Câmara Municipal de Ponta Delgada, Nova Gráfica, 2001).
  35. Ayres J. Corrêia, “Base Naval dos Estados Unidos da América do norte em Ponta Delgada: em política exterior dos Estados Unidos da América do Norte. O presidente Wilson e a guerra europeia—a ocupação das ilhas,” Revista Michaelense, no. 1 (1918): 76.
  36. Jon Tetsuro Sumida, “A Matter of Time: The Royal Navy and the Tactics of Decisive Battle 1912–1916,” Journal of Military History 67, no. 1 (January 2003): 85–136, https://doi:10.1353/jmh.2003.0075; and António J. Telo, “Os Açores e as estratégias para o Atlântico,” in Artur Teodoro de Matos, Avelino de Freitas de Meneses, and Jose Guilherme Reis Leite, História dos Açores—do descobrimento ao século XX, vol. 2 (Angra do Heroísmo, Portugal: Instituto Açoriano de Cultura, 2008).
  37. Christofer Waldenström, “Sea Control through the Eyes of the Person Who Does It: A Theoretical Field Analysis,” Naval War College Review 66, no. 1 (Winter 2013); and Tiago Moreira de Sá, História das relações Portugal–EUA (1776–2015) (Alfragide, Portugal: Dom Quixote, 2016).
  38. António José Telo and Augusto Salgado, A Grande Guerra no Atlântico Português, vol. 2 (Lisbon: Fronteira do Caos Editores, 2018).
  39. Jorge Borges de Macedo, História Diplomática Portuguesa—constantes e linhas de força—estudo de geopolítica (Lisbon: Instituto da Defesa Nacional, 1987).
  40. António M. Godinho, “Marines in the Azores Islands in World War I: Diary of Walter S. Poague,” Fortitudine 37, no. 1 (2012): 26.
  41. Telo, “Os Açores e as Estratégias para o Atlântico,” 217–64.
  42. The Tonopah (M 8) was originally launched as the USS Connecticut on 24 November 1900, was renamed Nevada in January 1901, and was commissioned on 5 March 1903. The ship was then renamed Tonopah on 2 March 1909 to allow Battleship No. 36 to be named Nevada. “M-8 USS Nevada,” NavSource Online: Battleship Photo Archive, accessed 10 October 2020.
  43. “Destroyers Americanos,” Açoriano Oriental, no. 4.289, 28 July 1917.
  44. Comando Militar dos Açores, Correspondência sobre a base naval americana/relatórios, Pastas de notas, 1919, CDZMA, FIA 15.
  45. António J. Telo, Os Açores e o Controlo do Atlântico, 1898–1948 (Lisbon: Edições Asa, 1993).
  46. “Herbert Dunn, RADM—Military Timeline,”, accessed 10 October 2020); and RAdm Herbert O. Dunn, commander, U.S. Naval Forces Based in the Azores to VAdm William S. Sims, commander, U.S. Naval Forces Operating in European Waters, 3 February 1918, NHHC, hereafter Dunn to Simms, 3 February 1918.
  47. “O caso da alfândega e os destroyers americanos,” Açoriano Oriental, no. 4.294, 1 September 1917. For example, the price of a chicken (750 reis or $194.95US 2019) would cost an additional 675 reis on board.
  48. The military commander of the Azores’s headquarters was transferred from Angra do Heroísmo (Terceira Island) to Ponta Delgada (São Miguel Island) from 12 December 1917 to 27 December 1918. This change was temporary and only for indispensable people and services dealing with foreign forces. The centralization of the Portuguese commands by one individual on an equal basis with the American admiral was deemed more critical.
  49. Sérgio Rezendes, A Grande Guerra nos Açores—Memória Histórica e Património Militar (Ponta Delgada: Letras Lavadas, 2014).
  50. Rezendes, A Grande Guerra nos Açores—Memória Histórica e Património Militar (2014). 
  51. For more information, see Naval Investigation: Hearings before the Subcommittee of the Committee on Naval Affairs, United States Senate, Sixty-sixth Congress Second Session, vol. 1 (Washington, DC: Government Printing Office, 1921), 136–38.
  52. RAdm Herbert O. Dunn, commander, U.S. Naval Forces Based in the Azores to VAdm William S. Sims, commander, U.S. Naval Forces Operating in European Waters, 15 February 1918, box 23, NHHC; and Dunn to Sims, 3 February 1918.
  53. Paul Kennedy, Strategy and Diplomacy, 1870–1945 (London: Fontana Press, 1989).
  54. José Leon Machado, Darkening Stars: A Novel of the Great War, trans. Milton M. Azevedo and Karen C. Sherwood Sotelino (Braga, Portugal: Edições Vercial, 2012); and Isabel Pestana, Memórias do General—Os meus três comandos de Fernando Tamagnini, parte 2 (Viseu, Portugal: SACRE/Fundação Mariana Alves, 2004).
  55. Sérgio Rezendes, A Grande Guerra nos Açores—Memória e Património Militar (Casal de Cambra, Portugal: Caleidoscópio, 2017).
  56. Dunn to Sims, 3 February 1918.
  57. LtCol Vírgilio Júlio Sousa (engineer) and Lt Carlos David Calder (artillery). The Portuguese major was José Pedro Soares, and the British officer is unknown. In a second meeting, Capt Holmes, USN, (infantry) was present. Rezendes, A Grande Guerra nos Açores (2017).
  58. Rezendes, A Grande Guerra nos Açores (2014).
  59. Portuguese terminology. J. B. Ferreira, Armas portáteis e Material de Artilharia (Lisbon: Imprensa Nacional, 1909).
  60. In position on 6 April 1918. RAdm Herbert O. Dunn, commander, U.S. Naval Forces Based in the Azores, to VAdm William S. Sims, commander, U.S. Naval Forces Operating in European Waters, 6 April 1918, NHHC. This letter mentions some of the principal U.S. ships at Ponta Delgada harbor. 
  61. Godinho, “Marines in the Azores Islands in World War I,” 25–33. This piece was produced for the 100th Marine Corps Aviation anniversary. 
  62. Walter S. Poague was born in Chicago, IL, on 21 August 1891, into the city’s high society. After graduating from the University of Chicago in 1914, he worked as a sales manager at the real estate mortgage department of the Woodlawn Trust and Savings Bank, where his father was the director. In June 1917, he decided to enlist in the Marine Corps and was sent to the Azores. 
  63. Godinho, “Marines in the Azores Islands in World War I”; and Hugo Cabral, “1st Marine Aeronautic Company—A primeira dos Marines, a primeira nos Açores,” Mais Alto 55, no. 427 (Maio/Junho 2017): 25–34.
  64. The aircraft were very similar in design being both biplanes with two seats; the main difference was that the R-6 had a more powerful engine at 200 horsepower and had two main pontoons, while the N-9 had a 100-horsepower engine with only one main pontoon. Godinho’s work reported the R-6s at 10, while Cabral’s counted only 8. Godinho, “Marines in the Azores Islands in World War I”; and Cabral, “1st Marine Aeronautic Company–A primeira dos Marines, a primeira nos Açores,” 25–34.
  65. One interesting note is the setup of operations for flights compared with a similar setup with Curtiss HS-1s at Pauillac, France. At Ponta Delgada, the Marines installed their facilities (from tents to machinery shops) in 25 days; in France, with facilities already in place, it took 20 days.
  66. Strange by current standards, at the time, a Marine only earned their wings as a naval aviator after completing basic instruction, integrating the operational units, and concluding the final tests.
  67. Godinho, “Marines in the Azores Islands in World War I,” 33.
  68. Godinho, “Marines in the Azores Islands in World War I,” 33.
  69. In addition, it had a new 330 horsepower Liberty engine, which were unlike the V2 (200 hp) or OXX3 (100 hp) engines to which they were accustomed.
  70. Poague, Diary and Letters of a Marine Aviator, 138–47.
  71. Poague, Diary and Letters of a Marine Aviator, 43.
  72. Poague, Diary and Letters of a Marine Aviator, 138–39.
  73. Godinho, “Marines in the Azores Islands in World War I,” 33; and “1Lt Walter Smith Poague,” memorial identification 75688814,, accessed 24 June 2021.
  74. Cabral, “1st Marine Aeronautic Company—A primeira dos Marines, a primeira nos Açores,” 25–34.
  75. Cópia da ata nº19 do Conselho Técnico, 18 February 1921, box 4183, Biblioteca Central de Marinha, Arquivo Historico, Direção da Aeronáutica Naval; Tradução do Acordo entre os governos dos Estados Unidos e Portuguez, para o estabelecimento de centros de aviação marítima em Ponta Delgada e na Horta, 14 June 1918, Biblioteca Publica e Arquivo Regional de Ponta Delgada (BPARPD); and “Processo de aviação Marítima,” (Agreement between the United States and Portugal for the Establishment of Naval Air Stations in Ponta Delgada and Horta), BPARD, Administração Central Delegada, Governo Civil de Ponta Delgada—Alto Comissário da República nos Açores, Repartição de Gabinete—Gabinete Militar 00021.
  76. The excitement of the American disembarkation was described by the monthly magazine Revista Micaelense. Ayres J. Corrêa, “A Base Naval dos estados Unidos da América do Norte em Ponta Delgada: em Política exterior dos estados Unidos na América do Norte—o presidente Wilson e a guerra europeia—a ocupação da ilha,” Revista Michaelense, Ponta Delgada, 1918.
  77. Ferreira, “Os Açores nas duas Guerras Mundiais.”
  78. Comando Militar Dos Açores, Ofício americano sobre exercícios navais, Pastas de notas, 1917, CDZMA, FIA 1230. 
  79. “Ofícios 44 a 46 de 28 de Julho de 1917,” in Livro 336 do Governador civil de Ponta Delgada: Correspondência expedida por este Governo Civil a diversas autoridades e pessoas, 1ª Secção, BPARPD, Fundo do Governo Civil de Ponta Delgada (FGCPD), 123–26.
  80. Sérgio Rezendes, A Grande Guerra nos AçoresPatrimónio e Memória Militar (Casal de Cambra: Caleidoscópio, 2017).
  81. RAdm Herbert O. Dunn, commander, Azores Detachment, letter to VAdm William S. Sims, commander, U.S. Naval Forces Operating in European Waters, 14 October 1918, NHHC.
  82. “Almirante H. O. Dunn—Na morte do comandante da base naval americana em Ponta Delgada durante a guerra europeia,” Correio dos Açores, no. 5.452, 9 March 1939; and “RAdm Herbert Omar Dunn,”, accessed October 6, 2020.
  83. “Azores Naval Base Made for Allied Naval Victory,” Chico (California) Record, no. 67, 20 March 1919, accessed 5 October 2020; and “Almirante H. O. Dunn,” Açoriano Oriental, no 4.378, 19 April 1919.
  84. “Azores Naval Base Made for Allied Naval Victory.” 
  85. Livro 342 do Governador civil de Ponta Delgada: Correspondência expedida por este Governo Civil a diversas autoridades e pessoas. 1ª Seção, BPARPD, FGCPD.
  86. Demobilization Plan—Memorandum No. 2, 14 November 1918, RG 45, entry 517B, NHHC.
  87. For example, the armed yacht Wadena (SP 158) on 26 July 1918. See Frank A. Blazich Jr., “United States Navy and World War I: 1914–1922,” NHHC (website), accessed October 9, 2020.
  88. RAdm Herbert O. Dunn, commander, U.S. Naval Forces Based in the Azores to VAdm William S. Sims, commander, U.S. Naval Forces Operating in European Waters, 17 August 1918, NHHC; and entry for 11 September 1918, Poague, Diary and Letters of a Marine Aviator, 128.
  89. For the convoy system in this part of the Atlantic, see the work of Augusto Salgado, for example, “The Convoy System in the Mid-Atlantic, 1917–1918,” The Mariner’s Mirror 105, no. 3 (2019); 288–96,
  90. Entries for 2 September 1918 and 9 October 1918, Poague, Diary and Letters of a Marine Aviator, 124, 138.
  91. Clark G. Reynolds, “Voyage of the NC-3,” Naval History Magazine 1, no. 1 (April 1987).
  92. José Meideros Ferreira, Portugal e os EUA nas Duas Guerras Mundiais: a Procuro de Plano Bi-Lateral (Lisbon, Portugal: Grupo de Estudos e Reflexão, Cadernos Navais, 2004). For the impact of WWI facilities in the Azores in a view after WWII, see Seward W. Livermore, “The Azores in American Strategy-Diplomacy, 1917–1919,” Journal of Modern History 20, no. 3 (September 1948): 197–211,
  93. Sérgio Rezendes, “Guerra Mundial, II: o contexto europeu e o interesse pelos Açores,” Cultura, Governo dos Açores (website), accessed 10 October 2020.
  94. “Chronology,” Arquivo & Biblioteca, Fundação Mário Soares and Maria Barroso (website), accessed 15 October 2020; and “Aeroporto de Santa Maria, História,” LPAZ—Associação para a Valorização e Promoção do Aeroporto de Santa Maria, accessed 15 October 2020.
  95. “Chronology: 30 May 19, Agreement with Great Britain and the United States for the Withdrawal of Lajes Base and Santa Maria Base on June 3,” Arquivo & Biblioteca, Fundação Mário Soares and Maria Barroso (website), accessed 15 October 2020; and “Lajes Field Air Force Base in Lajes, Portugal,”, accessed 15 October 2020.
  96. Today, it is home to the 65th Air Base Wing of the U.S. Air Force.
  97. Theodore Roosevelt (1909), Richard Nixon (1971 and 1974), George W. Bush (2003), and Barack Obama (2016); and U.S. Embassy and Consulate in Portugal, “U.S. and Portugal Meet on Economic Recovery, Foreign Policy Priorities, and Lajes,” press release, 15 July 2020.
  98. Record of 23d meeting, 8 February 1927, RG 117 entry 2, box 1a, binder 2, American Battle Monuments Commission (ABMC) Archives, 67.
  99. Record of 33d meeting, 1 December 1930, RG 117, entry 2, box 1a, binder 2, ABMC Archives.
  100. “Ponta Delgada assinala os 100 anos do bombardeamento da 1.a Guerra Mundial,” 5 July 2017, Rádio e Televisão de Portugal, video, 1:50min; and “Cem anos depois do primeiro voo nos Açores,” 17 February 2018, SIC Noticias, video, 1:28 min.


Dr. Sérgio Alberto Fontes Rezendes holds an undergraduate degree in history and social science, a master’s in cultural heritage and museology, and a PhD in insular (Azores) and Atlantic history. This article is derived from a portion of his master’s thesis, published by Letras Lavadas (1st ed., 2014) and Caleidoscópio (2d ed., 2017). Rezendes has served as vice director of the Military Museum of the Azores and also worked with the Military Museum of Lisbon and Military Historical Archives. Currently, he is a teacher at Castanheiro School in Ponta Delgada, Azores; serves as a collaborator of the Portuguese Coordinating Committee for the Evocation of the Centenary of World War I and of the Centro República; and is a post-doctoral researcher of the History, Territories and Communities Institute of the New University of Lisbon, Portugal. With six published books and many scientific works, Rezendes was appointed as a member of the Scientific and Pedagogical Commission of the Azorean government for the subject of history, geography, and culture of the Azores and by dispatch of the Portuguese National Defense Ministry, as a member of the Military Tourism Commission for the Azores, in 2014. As president of the Azorean Reserve Officer Association, he is the national representative to the Defense Attitudes and Security Issues Committee of the Interallied Confederation of Reserve Officers, North Atlantic Treaty Organization. This article derives in part from Sergio Rezendes, “World War I in the Azores: Historical Memory and Military Heritage” (master’s thesis, University of the Azores, 2008). The author thanks António Paulo Godinho and Hugo Cabral for their research about the 1st Marine Aeronautic Company in the Azores. The author also thanks Susan Burkat Trubey and translator Carolina Cordeiro for their language review of this article.

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