An official ceremony commemorating the induction of the non-nuclear submarine, S 81 Isaac Peral, into the Maritime Forces of the Spanish Navy took place in Cartagena on November 30, 2023. As part of the Spanish national project S-80 Plus (S-80A), this submarine was built at the facilities of the Spanish shipbuilding consortium Navantia. The Spanish fleet welcomed Isaac Peral as its first modern submarine since 1985.
The initial phase of the design and construction initiative spearheaded by Navantia for the four sizable non-nuclear submarines of the Spanish Navy designated S-80 (subsequently revised as S-80 Plus/S-80A) has been effectively completed. Nevertheless, it evolved into an extensive saga.
In 1991, in Spain, the conceptualisation of the S-80 program’s future submarine commenced. Izar, a consortium of the Spanish Navy, was awarded the contract in March 2004 to construct four submarines for this undertaking; delivery of the lead submarine was scheduled for 2011. The lead submarine, S 81 Isaac Peral, was initiated at the Izar facility (presently Navantia) in Cartagena in 2005. The remaining three submarines were constructed between 2007 and 2010. As a result of design errors, financial and technical complications, and extended construction times, the submarines necessitated numerous redesigns. The current estimate for the cost of the submarine is 4 billion euros, up from the contracted amount of 1,756 billion euros.
S 81 Isaac Peral, the lead submarine, left the shipyard’s slipway in Cartagena in April 16, 2021. The official inauguration ceremony from the floating dock into the water happened on May 7, 2021, while the formal launching ceremony occurred on April 22, 2021. The submarine underwent factory sea trials on May 27, 2022, and a year and a half were devoted to refinements and testing.
The initial intention was for every S-80 submarine to be outfitted with Air-Independent Propulsion (AIP). Since 2003, Navantia and the Spanish energy company Abengoa have been collaborating on developing AIP. Despite this, the development of AIP was also significantly delayed. The Spanish Air-Independent Propulsion system used in the S-80 submarine project operates on the principle of high-purity hydrogen production through the decomposition of bioethanol (BioEtOH) in specialised Coprox processor reactors. Hydrogen and oxygen that are produced are supplied to fuel cells that UTC Power has devised. In a cryogenic reservoir operating at high pressure, liquid oxygen is stored. In a mélange with seawater, the carbon dioxide produced during the decomposition of bioethanol is discharged overboard. At least 300 kW is the capacity of the S-80 Plus submarine’s AIP system, and the vessel is anticipated to have a 15-day submerged range and endurance.
The declaration of the AIP system’s readiness for serial production and the successful conclusion of bench tests was not made public by Navantia until February 2020. The decision was made to exclusively implement the AIP system during construction on the third (S 83 Cosme García) and fourth (S 84 Mateo García de los Reyes) submarines out of the four under construction due to development delays. The 2027-2028 deployment of these two submarines to the Spanish Navy is viewed with optimism. S 81 Isaac Peral and S 82 Narciso de Monturiol, the first two submarines of this type, were completed entirely on diesel-electric propulsion and are not anticipated to be retrofitted with AIP until their initial major overhauls. S 82 Narciso de Monturiol, the second submarine currently under construction, is slated to be launched during the final quarter of 2024, and its commissioning is anticipated by the conclusion of 2025.
With a maximum length of 80.81 metres and a complete underwater displacement of 3700 tonnes, the S-80 Plus submarines are large vessels.