Tecnico in 1936 at the age of 22, he went to work as a design and site engineer in charge of foundations and harbor projects for a German firm, Gruen and Bilfinger, A.G. From 1941 to 1943, he served in the Engineer Corps of the Portuguese Army. While stationed in the Azores, he met his future wife. The couple was married in 1944.
Vasco Costa held various academic positions at the two universities (they are affiliated) through 1980, when he became a full-time consulting engineer for harbor works in Lisbon. During his early years in academia (1946–1947), he was awarded a one-year scholarship in the United States—one semester at Cornell and one at the Bureau of Reclamation in Denver. In 1960, he was awarded a scholarship at the Hydraulics Research Station in Wallingford, England, where he worked on a thesis on the impact of vessels with berthing structures. During this period, he also founded CONSULMAR, an engineering consulting company; Fernando was director-general of the company from 1972 to 1980, and he worked there until his death in 1996. As a consultant, he participated in studies for all of the main Portuguese ports (Lisbon, Leixoes, Setubal, Sines, Viana do Castelo, Aveiro, Figueira da Foz, Portimao, Ponta Delgada, Funchal) and many foreign ports, such as Bissau (Guinea-Bissau), Ana Chaves (San Tome and Principe), Tenerife (Canary Islands), Mormugoa (India), Mocamedes (Angola), Maputo (Mozambique), and Ka-Ho (Macao).
The author of more than 50 papers and five books, mostly on various aspects of port engineering, Vasco Costa also wrote several papers on hydraulic modeling, another subject of great interest to him. He authored the Tabelas Tecnicas, a technical reference book used in Portugal by engineers for many years. He had a remarkable ability to combine a theoretical understanding of the physics of natural problems with the simplifications necessary to arrive at usable solutions—and an even more remarkable ability to express this understanding in terms that could be understood by others. His papers on the dynamics of berthing and mooring ships, including very large ships, were both theoretical and practical.
He was very involved in risk analysis of structures and structural