Spanish Submarine To Go Undetected Longer With World-first Propulsion System

Navantia’s shipyard in Cartagena has reached a major milestone with the installation of its air-independent propulsion (AIP) system on the Spanish Navy’s Cosme Garcia (S-83) submarine.

Navantia’s journey with the AIP system began with final testing completed in 2020, following the development of a new program specifically designed for the Spanish Navy’s S-80 class submarines. The AIP system, now being integrated into the Cosme Garcia, utilizes bioethanol as a sustainable fuel source to produce hydrogen onboard. This hydrogen, when combined with stored oxygen, powers a fuel cell that generates electricity to charge the submarine’s batteries, providing a reliable source of energy without the need to surface frequently for air intake, which is crucial for diesel engines.

This AIP technology offers a groundbreaking advantage, allowing S-80 class submarines to stay submerged twice to three times longer than conventional diesel-electric submarines. Extended underwater endurance greatly reduces the submarine’s detection risk, as the need to surface or “snorkel” for air intake is minimized. This feature is especially critical for naval missions where stealth is paramount, as submarines are most vulnerable to detection when partially exposed to water.

The Cosme Garcia (S-83) is the first of the S-80 class to be equipped with this advanced AIP system, and there are plans to extend this capability to other submarines in the class, including the Isaac Peral (S-81) and Narciso Monturiol (S-82), according to reports from Infodefensa. Navantia’s AIP system is said to operate effectively at any depth and in various operational conditions, making it highly versatile and suitable for a wide range of naval missions.

The S-80 Plus-class submarines, introduced with the commissioning of the Isaac Peral in November 2023, are unique in being the only 3,000-ton submarines equipped with an AIP system. This addition significantly enhances their endurance and range, optimizing them for extended missions. The S-80 Plus-class submarines, originally commissioned in 2003, faced delays and redesigns that resulted in their final delivery beginning in 2023. With a length of 266 feet and a submerged displacement of approximately 2,965 tons, these submarines are designed to achieve speeds of up to 19 knots underwater and 12 knots on the surface, giving them exceptional maneuverability and range.

Navantia has also highlighted the potential for further upgrades to the AIP system, allowing for even greater stealth capabilities. The design and production modifications could make the submarines almost undetectable, a significant selling point for potential international buyers.