Brazil Marks Major Submarine Milestones with Launch of Almirante Karam S43 and Advancement of Nuclear Program

Conventional Fleet Expansion Concludes with Almirante Karam S43 Launch

The Brazilian Navy celebrated a pivotal moment in its Submarine Development Program (PROSUB) on November 26, 2025, with the christening and launch of the conventional submarine Almirante Karam S43. The ceremony, held at the Itaguaí Naval Complex, marked the completion of the conventional construction phase of the program. The Almirante Karam S43 is the fourth and final unit of the Riachuelo-class, a derivative of the French Scorpène-class submarines, and was named after Admiral Alfredo Karam.

Following its launch, the Almirante Karam S43, which displaces approximately 1,900 tons submerged and measures about 70.62 meters in length, will undergo comprehensive harbor and sea trials. These trials are crucial for ensuring the proper functionality of its advanced systems, including diesel-electric propulsion, sophisticated sonar, and armament capabilities such as SM39 Exocet anti-ship missiles and F21 heavyweight torpedoes. Its delivery to the Submarine Force is anticipated in 2026.

Progress Continues on Nuclear-Powered Álvaro Alberto

Simultaneously, Brazil is making strides in the development of its first nuclear-powered attack submarine (SSN), the Álvaro Alberto (SN-10). This ambitious project is a cornerstone of Brazil's long-term naval strategy, aiming to enhance its maritime sovereignty and protect the vast oceanic area known as the 'Blue Amazon'. The official construction of the submarine's hull commenced with the first steel cut on June 12, 2024.

The Álvaro Alberto is designed to have a displacement of 6,000 tons and a length of 100 meters, powered by a pressurized water reactor (PWR) and a nuclear turbo-electric engine. While its launch is expected around 2029, commissioning is projected to occur between 2032 and 2034. Brazil is independently developing its nuclear propulsion system and mastering the nuclear fuel cycle, a critical component of this strategic endeavor.

PROSUB: A Strategic Partnership for Naval Modernization

The Submarine Development Program (PROSUB) was established in 2008 through a strategic partnership between Brazil and France's Naval Group. The program's objectives extend beyond merely acquiring new vessels; they include:

• Delivering a modern submarine fleet.
• Transferring critical technologies to Brazil.
• Building a sovereign naval industrial base within Brazil.
• Developing indigenous nuclear propulsion capabilities.

The creation of the Itaguaí Naval Complex has been instrumental in facilitating these goals, enabling Brazil to move towards independent design and construction of submarines on its own territory. The recent milestones signify Brazil's continued commitment to becoming a significant naval power in the South Atlantic.