If one looks at the evolution of conventional submarines, there is one constant that repeats itself: the race to stay underwater as long as possible. It is not just about speed or weapons, but about autonomy in immersion, a factor that directly determines the discretion of the platform and its patrol capacity. When a submarine has to interrupt that cycle to ventilate, manage gases or refuel, its operating margin is reduced. For this reason, much of the engineering behind the new submarines focuses precisely on solving that problem. And that is where the technology that Spain is integrating comes into play. in the S-80 program.
The jump of the S-80 submarine. Amper, through its engineering subsidiary Proes-OSL Iberia, delivered to Navantia the carbon monoxide (CO) and hydrogen (H₂) catalytic reactors for the submarines S-83 “Cosme García” and S-84 “Mateo García de los Reyes”. These devices are part of the atmosphere revitalization system, integrated into the AIP compartment. According to the company itself, the project started in 2022 and the equipment has already received official certification from Navantia after completing the corresponding technical verifications.
A key piece. The delivery announced by Amper has to do with a very specific element of the submarine’s technical ecosystem, the system responsible for maintaining the interior atmosphere within safe parameters during operation. Revitalization of the atmosphere in the submarine. The reactors developed by the company allow the controlled elimination of carbon monoxide and hydrogen in the compartment where the AIP system is integrated. The technology uses a catalytic combustion process that purifies these gases and helps maintain breathable air on board.
In detail. The S-80 incorporates an AIP system developed by Navantia called BEST (Bio-Ethanol Stealth Technology). This system produces hydrogen on board using a reformer that uses bioethanol stored on the submarine. This hydrogen is then combined with oxygen in a fuel cell that generates electricity to power the ship’s systems during the dive, an architecture designed to extend operational autonomy without depending exclusively on batteries.
What it means to stay underwater for weeks. Navantia explains that the BEST AIP system is designed to allow conventional submarines to remain submerged for prolonged periods in different environmental conditions. In that scenario, the unit reduces the need to interrupt its immersion cycle to manage power or interior atmosphere. Navantia links this greater autonomy with an expanded patrol area and with a “zero Indiscretion Coefficient”, a term it uses to describe a decrease in the probability of being detected during the mission.
modern submarine. The design of the S-80 responds to the idea of a modern ocean submarine capable of operating on long missions. Navantia describes the platform as a highly automated system that can be operated by a crew of 32 sailors, with eight additional spaces for on-board personnel. The ship is approximately 80 meters long, about 7 meters in diameter and has a submerged displacement of close to 3,000 tons. In addition, it can exceed 19 knots underwater speed and reach depths greater than 300 meters during operation.
Apparently it is just one more component in the long list of equipment that makes up a submarine. However, systems like these are part of a much broader logic within the S-80 design. Each of them contributes to sustaining the operation of the submarine for longer periods without the need to modify its diving profile. As subsequent units in the series integrate these developments from their initial configuration, the S-80 program will show the extent to which these technologies can translate into greater operational autonomy underwater.
Images | NAVANTIA

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