S-80 Plus-class submarine

S-80 Plus-class submarines are designed to improve threat scenario missions. Their operational mobility will allow them to operate in remote areas, traveling discreetly at high speeds. Their air independent propulsion (AIP) system, of new technological design, will ensure their ability to remain in an area for a very long period of time without being detected and their ability to operate in possible conflict zones.[4]

Capabilities include:

• A combat system for multiple target acquisition in different scenarios
• The ability to transport personnel, including special operations forces
• Low noise and magnetic signatures in order to minimize detection
• Low radar and infrared signatures in order to minimize detection

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. Provided by Hynergreen from Abengoa, the system transforms the bioethanol (BioEtOH) into high purity hydrogen. The output feeds a series of fuel cells from UTC Power company.

The Reformator is fed with bioethanol as fuel and oxygen (stored as a liquid in a high pressure cryogenic tank), generating hydrogen and carbon dioxide as subproducts. The produced hydrogen and more oxygen is fed to the fuel cells.

The bioethanol-processor also produces a stream of highly concentrated carbon dioxide and other trace gases that are not burned completely during combustion. This gas flow is mixed with sea water in one or more ejector venturi scrubber and then through a new system, SECO₂ (or CO₂ Removal System), developed by Bionet, and whose purpose is to dissolve the "bubbles" of CO₂ in water to undetectable levels.[5]

The oxygen and fuel flow rates are directly determined by the demand for power. The AIP power in the S-80 submarine is at least 300 kW (400 hp).[5] A permanent-magnet electric motor moves a fixed propeller of a special design, that doesn't create cavitations at high speed.

In the 1980s France began studies for the replacement of their S-60 Daphné-class diesel submarines. The French shipyard DCNI came up with an all-new design called S-80, with a teardrop hull and new weapons and sensors, which their government decided not to fund.[6] DCNI then proposed a cheaper option called the S-90B, an S-70 Agosta-class submarine with limited improvements which was again rejected by the French but which was exported to Pakistan.[6] Meanwhile, Spain faced the same problem in replacing their Daphnés, known as the Delfín class in Spanish service, as part of Plan ALTAMAR. Bazán (later Izar, and then Navantia) started on a new design but when it started to look like the S-80, it was agreed to collaborate in a joint venture based on the French S-80.[6] This joint design was shown at Le Bourget Navale in October 1990.[6]

The end of the Cold War meant that funding dried up and the joint venture had to wait until 1997 for their first sale - to Chile - of the new design,[7] which was designated the Scorpène class in export markets. The same year Spain started to look again at its requirements, and in 1998 they indicated that they would buy four Scorpènes,[6] optionally with an air-independent propulsion (AIP) system for greater endurance when submerged. A staff requirement for the S-80 Scorpène variant was completed in October 2001.[8] This was soon overtaken by events, as the Armada (navy) became more interested in using submarines for power projection than in a more static, defensive role.[8] This shift was codified in guidance of January 2002 from the Chief of Naval Operations and in the strategic defence review of February 2003.[8] The new requirement called for a larger submarine with better endurance and land-attack missiles, which became known as the S-80A design. This was an AIP submarine with a hull diameter of 7.3 metres (23 ft 11 in) compared to 6.2 metres (20 ft 4 in) for the Scorpène family, a submerged displacement of around 2,400 tonnes versus 1,740 tonnes, larger rudder surfaces and a different fin position.[8]

The Spanish government approved the purchase of four S-80A submarines in September 2003 and signed a contract with Izar on 24 March 2004.[9] The original deal was €1,756m to design and build four submarines,[9] about €439m per boat, but by 2010 this had increased to €2,212m[10] (€553m/boat). The plan envisaged the first boat to be delivered in 2011 but government dithering over who should supply the combat system pushed it back to 2013.[8] In 2011 Spain's budget crisis further delayed the first delivery until 2015, with the remaining boats being delivered at one year intervals until 2018.[11] Construction of S-81 began on 13 December 2007.[12] In January 2012 the names were announced, honouring three engineers who made submarines and the first commander of Spain's submarine force respectively - Isaac Peral (S-81), Narciso Monturiol (S-82),[13] Cosme García (S-83) and Mateo García de los Reyes (S-84).[14]

In May 2013, Navantia announced that a serious weight imbalance design flaw had been identified which will delay the delivery of the first submarine to the Spanish Navy until possibly 2017.[15] Lengthening the submarine created additional buoyancy.[16] Navantia signed on the US company General Dynamics Electric Boat to help solve the excess weight.[17] In September 2014, the detected overweight was reported to have been resolved and the construction work to be ready to resume in late October 2014.[18] In November 2014, Navantia again reported having completed the redesign work to address the problem of overweight. In all, the hull will be lengthened by seven metres, and the displacement increased by 75 tons. As of January 2018, the intended delivery date of the first submarine is September 2022.[19] In January 2017, it was reported that the AIP system would not be ready in time for the delivery of the first submarine.[20] In November 2018 the companies Abengoa and Tecnicas Reunidas, said they had completed in an excellent way, their tests for the revolutionary AIP engine of the submarine.[21] The Indian Navy considered the S-80 for its next generation of submarines under Project 75I.[22]

• List of submarine classes in service

This article incorporates material from Spanish Wikipedia