Brazilian Submarine Force

The Submarine Force (Portuguese: Força de Submarinos; ForSub) of the Brazilian Navy is the component of the Fleet that organizes these assets and their naval bases, auxiliary vessels, training schools, and divers. Its operational components comprise four submarines, one rescue ship, one aviso, and a special operations unit, the Combat Divers Group. Its main anchorage and command headquarters is Madeira Island, in Itaguaí, with additional facilities on Mocanguê Grande Island, in Niterói–both in the state of Rio de Janeiro.

Brazil has operated submarines since 1914, beginning with the Foca class. Historically, there has been an average of four to five submarines in service, with a peak of ten in 1977–1978. They were built abroad until the 1980s, when Brazilian industry became the first in the Southern Hemisphere to assemble submarines. The technological source shifted from Italy to the United States, the United Kingdom, Germany, and currently France. From the Second World War to the early Cold War, during the Italian and American phases, priority was given to training surface forces in anti-submarine warfare.

From the 1970s onward, Navy strategists rethought submarines as elements of a balanced blue-water fleet and/or as instruments for sea denial in a defensive campaign off the coast. The 2008 National Defense Strategy confirmed their priority on the Navy's agenda, and since then the Submarine Development Program (ProSub) has aimed to build a mixed fleet of conventionally armed submarines with conventional (diesel-electric) propulsion and nuclear propulsion in Brazil. The conventional submarines–the only type currently in service–are more suitable for positional warfare. The future Brazilian nuclear-powered submarine will be a complementary platform with greater autonomy and mobility, officially intended for deterrence and the patrol of jurisdictional waters.

Brazilian submariners are volunteers trained at the Admiral Áttila Monteiro Aché Training and Instruction Center (CIAMA). The career of a submarine crew member is prestigious, highly specialized, and psychologically demanding. The working environment is isolated, confined, artificial, and has its own culture. Risks are constant. The largest accident in ForSub's history was the sinking of Tonelero (S-21) at the pier in 2000, but there were no fatalities or injuries.