As part of the preparatory tasks prior to its entry into service, the Brazilian Navy conducted the first navigation and static dive tests of the new Riachuelo-class submarine Tonelero (S-42).
The maneuvers, carried out on Friday 25 and Saturday 26, consisted in the first sea launch of the “Tonelero” by its own means, and the static immersion test, which took place in the Sepetiba Bay, near the Itaguaí Naval Complex, where the new MB submarines are being built. Stability tests were also carried out, the purpose of which is to calculate the displacement of the submarine on the surface and in immersion to ensure the safe performance of the sea trials.
During open-sea navigation, various onboard systems were inspected and operationally verified to comply with safety procedures. These included testing the radar systems, observation and optronic periscopes, navigation systems, echo sounder, communications, cavitation and noise emission, sonar, and underwater telephony.
Concluding this phase, on Saturday the 26th, the Rescue Watch test was conducted, designed to allow the submarine to execute an emergency dive if it is unable to return to the surface, thereby ensuring the safe execution of the submarine’s first dynamic dive, scheduled for January 2025.
Prior to these initial sea trials, the Tonelero underwent buoyancy tests last August after leaving the Itaguaí Naval Construction Complex (ICN) dry dock. It is the third unit of the Submarine Development Program (PROSUB), belonging to the Riachuelo Class, built locally with assistance from the Naval Group.
The Tonelero will be the second unit to enter service with the Brazilian Navy, with its definitive incorporation estimated for 2025, further demonstrating the progress of the PROSUB program. The program has already delivered two units now in service: the Riachuelo (S-40), after which the Scorpène-class was named in Brazil, and the Humaitá (S-41), which entered service in 2022 and early 2024, respectively.
Meanwhile, the final submarine of this class, the Angostura (S-43), is advancing in construction, while the initial stages of building the future nuclear submarine Álvaro Alberto have begun, expected to enter service within the next decade.
Images used for illustrative purposes. Credits: ICN
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