Navantia S-80 Plus submarine is going through a decisive moment as it aims for the Indian Navy P-75I tender

One of the most critical programs for Spanish defense and industry, the Navantia S-80 Plus submarine, is going through a decisive moment given the imminent sea trials of the first unit, the Isaac Peral, and progress in the construction of the other three units, especially the second, the Narciso Monturiol.

The delays in the program have forced the Spanish Navy to extend beyond the planned operational life of its only two S-70 type submarines currently in service, also built by Navantia in the first half of the 1980s, with the assistance of the French design company now known as Naval Group.

The refurbishment of the extraordinarily large hull of the fourth flagship of the Galerna Class (S-71) is currently in the completion phase. The Tramontana (S- 74), which is scheduled for decommissioning in February next year, has been approved for the extension of its operational life for one more year with consultation with the Naval Group, which is the design authority of the type S-70. The fleet can count on at least two submarines, one of them operational. Life extension of the submarine is essential for Spain. 

The S-80 Plus program follows a regulated systems engineering process. It is necessary to pass a series of technical or quality reviews, in which it must demonstrate that the submarine is mature to move on to the next phase. Engine start-up is the fourth safety milestone, after power-up, battery loading and launching. The S-80 Plus has engines equipped with the DAR system (Diesel Alternator Rectifiers), which allow the charging of their batteries or directly supply energy to the main electric motor. The diesel engines are manufactured by the Navantia Motors factory (also in Cartagena) under licence from German company MTU.

In the coming months, the S-81 will undergo the first battery charges with the DAR and the test on moorings before the sea trials. In addition, in the dock, workers continue to complete the installation work of the sensors, the eyes and ears of the submarine. The submarine periscope has been replaced with an optronic mast, which provides more information about location and dimension compared to the conventional periscopes. 

The snorkel is a much improved Dutch design from the World War II era, which allows more air intake for the operation of diesel engines at periscope depth. 

The initial objective is to deliver the S-81 to the Spanish Navy in the first quarter of 2023. A lot of work remains in 2022 in which the critical sea trials will be carried out, scheduled for the beginning of this year. 

In addition to this milestone, Navantia is also working hard on the other three submarines that make up the Class, which are the Narciso Monturiol (S-82), the Cosme Garcia (S-83) and the Mateo Garcia de los Reyes (S-84), with approximate delivery dates in 2024, 2026 and 2028. 

The air independent propulsion module (AIP), which allows the submarine to transit for up to 3 weeks without taking oxygen from the outside, will be installed in S-83 and later in all three submarines.

The S-80’s Air Independent Propulsion (AIP) system is based on a bioethanol processor consisting of a reaction chamber and several intermediate Coprox reactors. The system is supplied by Abengoa’s Hynergreen and transforms bioethanol (BioEtOH) into high purity hydrogen. The output feeds a series of fuel cells from the company UTC Power.

The Cofferdam made with maximum resistance steel will facilitate the entrance and departure of divers or evacuation if necessary. 

Close to entering service, the S-80 Plus is one of the most cutting-edge products promoted by Navantia at fairs and exhibitions.

Navantia’s current main objective is to win the tender from the Indian Navy, called P75I, through which it will equip itself with six submarines with AIP. The Spanish company is one of the five companies shortlisted to win the contract, along with rivals such as Naval Group (France, Scorpene), ThyssenKrupp Marine Systems (TKMS) (Germany, Type 214), Rubin (Russia, Amur 1650) and Daewoo Shipbuilding & Marine Engineering (DSME) from South Korea.

Spain more open to technology transfer to India

Navantia held an online meeting in April 2020 with more than a hundred Indian companies interested in being part of its network of local suppliers in the P-75I program.

In April 2021, Navantia’s International Commercial Director, Abel Mendez Diaz, was on Indian television, underlining that the Spanish company is committed to a technology transfer program within the P75-I project to provide its Indian partner with the necessary knowledge for the construction of submarines.  

He said that Navantia offers full collaboration for the construction in India by local submarine companies. The company has already contacted more than a hundred potential suppliers in India, with whom it is studying the options that exist for the supply of equipment and main materials and the opportunities for technology transfer.

The offer includes the AIP system, dubbed Bio Ethanol Stealth Technology (BEST), and plans to incorporate additional features that increase existing capacities, such as lithium-ion batteries.

The S-80 Plus class submarines have a total load displacement of 3,200 tons, an overall length of 81.05m, a beam of 11.68m and a draft of 6.20m. With a cruising speed of 12 knots, the S-80 Plus class submarines offer a range of 8,000 nautical miles. The submarine accommodates 32 pax crew and eight marines/commandos. The Spanish Navy S-80 Plus class submarine is equipped with six × 533 mm torpedo tubes with DM2A4 torpedoes and Harpoon missiles.