Madeira Island Submarine Base (BSIM)

Madeira Island Submarine Base (Base de Submarinos da Ilha da Madeira, BSIM) is a Brazilian Navy submarine base at Itaguaí, in the state of Rio de Janeiro, on Sepetiba Bay. The installation is closed to the public and forms part of the Itaguaí naval complex.

Since 12 July 2021 the base has been the seat of the Brazilian Submarine Force Command (ComForS), transferred there by the Navy from its previous location. It supports the Scorpène-derived Riachuelo-class boats, the first of which, Riachuelo (S40), was launched on 14 December 2018, followed by Humaitá (S41) on 11 December 2020. Tonelero (S42) and Almirante Karam (S43) entered construction in 2017 and 2018 respectively.

The site houses the headquarters of Itaguaí Construções Navais, the shipbuilder responsible for the submarine programme, and the associated construction halls and launch facilities. Since 2018 the yard has also been the build site for the nuclear-powered submarine Álvaro Alberto.

The base was conceived to receive construction of the Navy's new submarines and to accommodate the shipbuilder, entering use in 2020 under the Submarine Development Program.