Gago Coutinho (1869-1959)

Carlos Viegas Gago Coutinho was born in Belém, Lisbon, on 17 February 1869. He was the son of José Viegas Gago Coutinho and Fortunata Maria Coutinho. In 1885, he concluded his secondary education and then enrolled at the Polytechnic in order to prepare his entrance into the Navy School one year later. He entered the navy as a naval cadet in 1886. In 1890, he was promoted to midshipman, in 1891 to second lieutenant and in 1895 he became first lieutenant. In 1907, he was promoted to the position of lieutenant and in 1915 to commander. In 1920, he became captain. In 1922, he was promoted to vice-admiral and in 1958 to admiral.

Gago Coutinho’s activity can be divided into four main areas that follow each other chronologically: navy, especially from 1893 to 1898; geographical works, between 1898 an 1920; aerial navigation, from 1919 to 1927; and nautical history and the history of the discoveries, from 1925 to 1958.

His first long embarkation was aboard the corvette “Afonso de Albuquerque”, from 7 December 1888 to 16 January 1891, on a voyage to Mozambique and in the West African Naval Division. From this corvette he passed on to the gunboat “Zaire”, where he remained until 24 April 1891, travelling to Lisbon. After his placement in the West African Naval Division, he embarked successively on the launch gunboat “Loge”, which he commanded, on the gunboat “Limpopo”, on the gunboat “Zambeze” and on the corvette “Mindelo”. On service in this corvette in Brazil in 1894, he contracted yellow fever and had to be admitted to the Hospital da Beneficência Portuguesa in Rio de Janeiro. Once back in Portugal, he spent some time on board the gunboat “Liberal” and in the corvette “Duque da Terceira”. He underwent a new journey in the North Atlantic in the corvette “Duque da Terceira”. He travelled up to Mozambique aboard the “Pero de Alenquer” and then changed over to the corvette “Rainha de Portugal”, and then to the gunboat “Douro”, which brought him back to Lisbon. He then embarked on the battleship “Vasco da Gama”, until 31 March 1898, moving on to his first ultramarine geographer commission in Timor.

From March 1989 onwards, most of Gago Coutinho’s activity was developed within the framework of the Cartography Commission, created in 1883, first on field works to mark off borders or geodesics processed in Timor, Mozambique, Angola and S. Tomé, and as from 1919 as a member of this Commission. He presided over its destinations from 1925 onwards until it was transformed into the Junta de Investigações do Ultramar in 1936.

Between 27 July 1898 and 19 April 1899, Gago Coutinho was involved in field works, in marking off the borders of Timor and in drawing up the map of this territory. On return to Portugal, he was nominated to mark off the borders in Niassa, a mission that took place between 5 September 1900 and 28 February 1901. He then left for Angola, where he dedicated himself to marking off the border of Noqui with the Cuango River until the end of 1901. He was then involved in marking off the borders in the Tete district, in Mozambique, between 27 February 1904 and 18 December 1905.

He was nominated head of the Geodesic Mission of West Africa, having worked for this mission for approximately 4 years, from May 1907 up until the beginning of 1911. It was on this mission that he met Sacadura Cabral, whom he befriended and who would become the mentor of the future aerial navigation projects. Immediately afterwards he was chosen to lead the Portuguese mission to mark off the border of Angola in Barotze, which was only finally established in 1912. On return to Portugal in 1914, he was nominated head of the Geodesic Mission of S. Tomé in 1915.

His works at the service of the Cartography Commission were interrupted during the periods in which he was on board the gunboats “Sado” in India and “Pátria” in Timor, from September 1911 to August 1912, and from March 1922 to December 1923, when he made the aerial crossing from Lisbon to Rio de Janeiro.

(clique na imagem acima para ver ampliação)
Hidroavião bimotor Felixtowe F.3, utilizado por Gago Coutinho e Sacadura Cabral na viagem Lisboa-Funhal

(clique na imagem acima para ver ampliação)
Sextante de Gago Coutinho usado
na travessia do Atlântico.

In mid-1919, encouraged by Sacadura Cabral, when he was completing the work related to the geodesic mission of S. Tomé, Gago Coutinho started dedicating himself to the progress of aerial navigation methods. Cabral and Coutinho had flown together for the first time in 1917. Sacadura Cabral had already planned the aerial voyage to Brazil, which he intended making on the one-hundredth anniversary of the independence of this country, in 1922. Gago Coutinho therefore started dedicating himself to resolving the problems that faced aerial navigation with no points of reference on the surface. In order to try out the aerial navigation process under study, Sacadura Cabral and Gago Coutinho undertook several voyages together, including the first aerial voyage between Lisbon and Funchal in 1921, taking this opportunity to update the observation methods under development. These studies culminated in 1922 with the aerial voyage between Lisbon and Rio de Janeiro.

He was a member of several scientific associations, namely the Academia das Ciências, the Academia Portuguesa de História, the Sociedade de Geografia de Lisboa and several Geography Societies of Brazil, among others.

Scientific Activity

Gago Coutinho carried out many border-marking missions in the Portuguese colonies, namely in Timor, Mozambique and Angola. In Timor, he marked off the border with the part of the island occupied by the Dutch at the time, in the years 1898 and 1899. In Mozambique, he marked off the borders in the Zambeze and in lake Niassa in the year 1900, also setting up triangulations. In 1901 and 1902, he led the team that marked off the borders in the North of Angola, between this colony and the Belgian Congo. Between 1907 and 1910, he worked in Mozambique once more, returning to Angola in 1912 on a mission to mark off the western border with Rhodesia. Between 1915 and 1918, he led the geodesic mission in S. Tomé, where he set up milestones to establish a geodesic network of the island, after which he made triangulation observations, measured the precision of two bases and countless astronomical observations. During these observations, he confirmed the passing of the equator through the islet of Rolas. The map resulting from these observations was delivered in 1919, together with the Relatório da Missão Geodésica da Ilha de S- Tomé 1915-1918, which was officially considered to be the first complete geodesic work of one of the Portuguese colonies.

Gago Countinho died in Lisbon on 18 February 1959.

What made Gago Countinho famous was his pioneering scientific work in astronomical aerial navigation and his first crossing of the Southern Atlantic between Lisbon and Rio de Janeiro with Sacadura Cabral. Right from the first time he flew with Sacadura Cabral in 1917, Gago Countinho tried to resolve the problems facing astronomical aerial navigation. One of the main problems was the difficulty in defining the line of the horizon at a normal flying height. The difficulty in making precise measurements of the flying position with an ordinary sextant raised problems of an instrumental and methodical nature.

In order to resolve the problem of measuring the altitude of a celestial body without a sea horizon, Gago Countinho designed the first sextant with an artificial horizon that could be used on board aircraft. This instrument, which Gago Coutinho called the “precision astrolabe”, makes it possible to materialise an artificial horizon using a spirit-level and also has an electrical system lighting up the spirit-level, making night-time observations possible. Between 1919 and 1938, Gago Coutinho dedicated himself to perfecting this instrument, which was later manufactured and made known by the German constructor C. Plath under the name “System Admiral Gago Coutinho”.


Corrector de rumos

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Coutinho Sacadura route corrector used in navigation.

(click on the picture to see an enlarged version)

Route of the journey from Lisbon to Rio de Janeiro

Lusitanian hydroplane in which Gago Coutinho and Sacadura Cabral left Lisbon on 30 March 1922.

Hydroplane Santa Cruz in which Gago Coutinho and Sacadura Cabral completed the last part of the journey between Lisbon and Rio de Janeiro, on exhibition at the Museu de Marinha in Lisbon.

In collaboration with Sacadura Cabral, he designed and built another instrument which they called the “Plaqué de abatimento” or “route corrector”, which made it possible to graphically calculate the angle between the longitudinal angle of the aircraft and the route to be followed, taking the intensity and direction of the wind into account.

In order to verify the effectiveness of their methods and instruments, Gago Coutinho and Sacadura Cabral made several aerial voyages, one of which was the journey between Lisbon and Funchal in 1921, in approximately seven and a half hours. On this journey, Gago Coutinho performed 15 calculations of straight altitude lines and several observations of the strength and direction of the wind. According to his annotations, the navigation processes used “were sufficient to determine with precision any point away from the earth, as small as it might be, a resource which became essential in a projected aerial journey from Lisbon to Brazil”. The journey that finally demonstrated to the entire world the value of these instruments and methods was the aerial crossing of the South Atlantic Ocean, between Lisbon and Rio de Janeiro, between 30 March and 17 June 1922.

After this journey and the subsequent homage and official receptions, Gago Coutinho continued to work for the Cartography Commission, dedicating most of his time to the history of the voyages of the discoveries in the fifteenth and sixteenths centuries, having published many texts in which he analysed the methods used and tried to explain how the Portuguese managed to navigate so far from the coast and to sight land in the fifteenth and sixteenth centuries. From his sail navigation experiences in several ships in which he rendered service, he tried to explain how the Portuguese used the most appropriate methods at the time to stand up to the winds and crosscurrents.

He made several journeys in which he practised making observations using an astrolabe similar to those used by the Portuguese in the fifteenth century, comparing its results with those obtained in sextants and chronometers with the aid of a radio signal. From these studies he concluded that the experience of the Portuguese navigators of the time of the discoveries was decisive in making astronomical navigation possible and that journeys were duly planned based on experience and that their return routes were not the result of storms and other unforeseen events, as defended by some historians. Worthy of particular mention are his studies on the regime of winds and currents in the North Atlantic, which forced the Portuguese navigators to sail around the crosscurrents and winds in deep sea on return from Guinea or Mina. This manoeuvre, called the detour of Guinea or detour of Mina, and which Gago Coutinho habitually called “the off-sea detour“, started being practised in the mid-fifteenth century. By the start of the sixteenth century, it had become routine navigation.


Fernando Reis  


The only publication in book form was the Relatório da Missão Geodésica da Ilha de S. Tomé 1915-1918. However, he published numerous works in periodic publications, many of these works having been put together into two volumes organised and prefaced by Commander Moura Brás: A náutica dos descobrimentos. Os descobrimentos marítimos vistos por um navegador: colectânea de artigos, conferências e trabalhos inéditos do Almirante Gago Coutinho, Lisbon, Agência Geral do Ultramar, 1951-1952, 2 vols.

Many other texts were published in two volumes edited by Teixeira da Mota: Obras completas de Gago Coutinho, Lisbon, Junta de Investigações do Ultramar, 1972.


ALBUQUERQUE, Luís de, Curso de História da Náutica, Lisboa, Alfa, 1989.

BOLÉO, José de Oliveira, Gago Coutinho e Sacadura Cabral, Lisboa, Sociedade de Geografia, 1972.

CORRÊA, Pinheiro, Gago Coutinho, Precursor da Navegação Aérea, Porto, Portucalense Editora, 1969.

Correia, José Pedro Pinheiro,

LEMOS; Carlos M. Oliveira e, O Almirante Gago Coutinho, Lisboa, Instituto Hidrográfico, 2000.

REIS, Manuel dos, CORTESÃO, Armando, Gago Coutinho Geógrafo, Coimbra, Junta de Investigações do Ultramar, 1970, sep. de Memórias da Academia das Ciências de Lisboa, Tomo XIII, 1969.


Aeromodelismo e Aviação em Portugal

Raid Aéreo Lisboa-Rio de Janeiro 1922-2002

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