S-80A

Spain’s S-80A submarine comes up to the surfaceNavantia believes the Armada Española’s next-generation S-80A design will establish its credentials as a submarine prime contractor and systems integrator. Richard Scott reports on the evolution and contents of the submarine programme

26 jni.janes.com ■ JANE’S NAVY INTERNATIONAL DECEMBER 2007

A cigar-shaped steel hull sited to over-look the waterfront in the historic naval port of Cartagena, on the

southeast coast of the Iberian peninsula, serves as a reminder that Spain has been involved in the design and construction of submarines for more than 120 years.

This monument is in fact the Isaac Peral, the world’s fi rst electrically powered sub-mersible vessel, launched from the San Fernando shipyard in 1888.

Although primitive by modern standards, it was in its day a trailblazer. As well as pioneering new concepts in hull design, it also demonstrated its ability to fi re White-head torpedoes and maintain full propul-

sive power and control while submerged. Today, just over 1 km from where this

little piece of naval history stands, the frames are being welded and the steel shaped at Navantia’s Cartagena shipyard for a new class of submarine some 10 gen-erations removed from Isaac Peral. These are the structures of the new S-80A design, the most advanced submarine ever to be built for the Armada Española and, accord-ing to both Navantia and its customer, a true ocean-going force-projection asset that will set new standards in non-nuclear submarine performance when delivered in 2013. Indeed, putting aside the absolute speed, mobility and power available to a

nuclear-powered attack submarine (SSN), the S-80A weapon system will be similar to that of a modern SSN in many respects, including the ability to fi re land-attack cruise missiles.

A fi rst few rings of the pressure hull of the fi rst of class — the as yet unnamed S-81 — are already assembled. However, it will be the conclusion of the programme’s Crit ical Design Review, scheduled for sign-ing off at the end of November 2007, that will sanction the release of detailed engi-neering drawings to the shopfl oor.

In advance, Navantia has already com-pleted source selection and concluded commercial terms for all major S-80A

Artist’s impression of the S-80A submarine at sea. Rejecting suggestions that it is merely a scaled-up derivative of the Scorpene, Navantia insists the S-80A is “all new from the keel up”.

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DECEMBER 2007 JANE’S NAVY INTERNATIONAL ■ jni.janes.com 27

subsystems, contracting for equipment from a diverse international supplier base. Its 400-strong engineering team has been utilising the FORAN computer-aided design (CAD) tool to progressively refi ne the three-dimen-sional electronic design in preparation for its release to manufacture.

Additionally, a series of land-based test facilities are beginning to take shape to de-risk and demonstrate a number of dev-elopmental inte grated systems critical to the capability of the submarine.

While the S-80A design solution has been driven by the specifi c operational require-ments of the Spanish Navy, Navantia also sees it as the baseline for an export design intended to compete at the ‘high end’ of the non-nuclear submarine market. Having latterly collaborated with France’s DCNS on the Scorpene design — sold to Chile, India and Malaysia — Navantia believes it is ready to strike out alone in an effort to replicate the international success already enjoyed by its surface shipbuilding arm; indeed, Turkey has publicly declared the S-80A as one of the candidates for its next submarine requirement alongside rival pro-posals from DCNS and ThyssenKrupp-owned HDW.

Of course, the challenges inherent in the design, development, manufacture, in-tegration, test and acceptance of a brand new submarine design — and one incorp-or ating so many new-to-type systems — are not lost on any independent observer, nor on Navantia’s project management team. The chronic problems and delays affl icting the Royal Australian Navy’s Col-lins-class submarine programme perhaps resonate most, given that this was a simi-larly ambitious and complex engineering endeavour that also attempted to emu-late many of the fi ghting characteris-tics of an SSN.

While by no means complacent, Navantia believes its experience as a platform system integrator, rather than a submarine builder per se, will count in its favour. So too, it suggests, will the experience of its Faba Systems subsidiary, which is taking a piv-otal role as design authority for the supply of the Integrated Platform Management System (IPMS) and, in partnership with Lockheed Martin, the combat system core.

Different beastsThe very provenance of the S-80A design is something that Navantia is anxious to clarify, the company de-basing the miscon-ception that it is nothing more than a scaled-up derivative of the Scorpene export design jointly offered to the international market in partnership with DCNS. While the two designs may exhibit a superfi cial resemblance in their general arrangement and hydrodynamic form, they are in fact very different beasts in terms of their size, engineering design, equipment outfi t and operational performance, according to Fer-nando Miguelez, director of Navantia’s Cartagena shipyard.

“The simple fact is that the S-80A is an all-new design from the keel up… there has been nothing taken from the Scorpene, and the two project teams are run by different managers in different buildings,” he says. “This is a new submarine designed from scratch by Navantia to match the Spanish Navy’s specifi c operational requirement and operating profi le, which calls for a submarine offering performance some way in excess of the Scorpene.

“Whereas the Scorpene is very much a defensive

submarine, designed for ASW [anti-

submarine

warfare] and ASuW [anti-surface warfare] in local waters, the S-80A is a far more able ocean-capable design, incorporating AIP [air-independent propulsion] as standard, offer-ing longer range and endurance, and afford-ing a strategic force-projection capability.”

Like for like, the S-80A is about 30 per cent bigger than the Scorpene (it is only 4.5 m longer but has a larger hull diameter of 7.3 m vice 6.2 m). Submerged displacement works out at 2,400 tonnes, signifi cantly greater than the 1,740 tonnes of the Scorpene.

“There are also important differences in the hydrodynamic form,” says Miguelez. “Yes, the two designs share a classic Alba-core hullform, but the S-80A has some-what larger rudder control surfaces, and the fi n position on the hull is different.”

It is, however, ‘under the skin’ where the different genealogy of the S-80A becomes far more apparent. “The Scorpene is an export design which, for quite obvious rea-sons, is largely based on systems and equip-ment provided by a French supplier base,” Miguelez points out.

He continues: “As Spanish industry only offers solutions in certain niche areas, for the S-80A we have gone out to the world market to source the ‘best of breed’ equip-ment to suit the Spanish Navy’s perfor-mance specifi cation.”

The end result, he says, will be “a highly automated, ultra-quiet boat with a com-pletely new set of equipment being supplied from a wide range of vendors across plat-forms, machinery and combat systems”.

There are also several technical innova-tions that mark the S-80A out from the crowd. “We are installing a new AIP system based on the use of Ethanol reformer cell technology; adopting a truly open, inte-grated combat system architecture; and using a positive discharge weapon launch system that will be fully prepared for the

The fi rst pressure hull rings for S-81 are taking shape inside Navantia’s Cartagena yard.

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Tomahawk land attack missile from the outset,” Miguelez says. “We are also intro-ducing a high level of automation into the design to permit a crew of just 32.”

Origins in ALTAMARThe genesis of what was, in its original form, the Serie 80 (S-80) programme can be traced as far back as 1989 when the Arm ada fi rst promulgated its ambitious recapitalisation programme under Plan ALTAMAR. Early submarine concept and feasibility study work concluded in 1991, but it was not until July 1997 that S-80 project activity began in earnest.

A mission needs document was approved in September that year, with a draft naval staff target circulated in November and subsequently formalised in April 1998. Foll-owing approval of the formal naval staff requirement by the Almirante Jefe del Est-ado Mayor de la Armada (AJEMA) in Oct-ober 1998, Empresa Nacional Bazan (later incarnated as IZAR and latterly Navantia) was awarded a two-year project defi nition contract in November 1999. This activity concluded in October 2001.

At this juncture the development pro-gramme took a new turn. The Spanish Navy, in reviewing the original require-ments captured in its statement of oper-ational need, judged that the staff require-ment needed to better refl ect new missions and operating patterns consequent of the changed post-Cold War strategic situation. As a result, the naval staff requirement was revisited and updated, being approved by the AJEMA in its new form in July 2002.

Speaking at the IQPC Underwater Bat-tlespace conference in London, UK, in January 2005, the then commander of the Spanish submarine fl otilla, Captain Jaime Munoz-Delgado, described the changes

impacting his command and the submarine community as a whole. “The strategic guid-ance issued by the AJEMA in January 2002 made it clear that naval operations involving power projection over land and protecting naval and land forces in shallow waters are more likely than conventional naval combat,” he said. “For the submarine force, that means building on our classic missions of anti-sub-marine warfare and anti-surface warfare to embrace a range of additional tasks.

“These include naval power projection; support to special operations; intelligence, surveillance and reconnaissance; indicators and warnings; amphibious/land force pro-tection; deterrence; offensive mining; task group support; and naval force protection.

“A consequence of this was the need to look again at the staff requirement for the S-80. In particular, we confi rmed the need for AIP, which was previously regarded as an option only.”

Capt Munoz-Delgado added: “We also recognised the need for the submarine to make a substantial contribution at force level. This demands a reliable and assured system of communications and real-time information exchange.”

This new thinking was enshrined by the Spanish government’s strategic defence review, published in February 2003, which reaffi rmed the need to acquire a new sub-marine capability. It also set out a require-ment to have a minimum of two submarines available to be deployed concurrently on separate operations; noted the importance of AIP to extend submerged endurance; and recognised the ability of submarines to con-tribute to force projection by launching deep-strike weapons against land targets.

The corollary for the S-80 programme was a second defi nition phase, starting in November 2002, that saw IZAR (as was) tasked to re-engineer the original design to

meet the updated requirements set. This resulted in a larger-diameter boat re-desig-nated as S-80A, the ‘A’ suffi x being added to indicate the substantial evolution from the original S-80 concept.

A government go-ahead for the S-80A programme fi nally arrived in September 2003. This was followed in March 2004 by the award of a design-and-build contract to what is now Navantia, for an initial four boats to be delivered from 2011.

However, a government-led decision on the principal industry partner for the combat system was not forthcoming until 2005. This delay has had a signifi cant impact on the master schedule, given the complex inter-dependencies between the platform and combat system, with the delivery of S-81 now re-baselined for 2013. All three follow-on boats are due for handover by the end of 2015.

Design aspectsAdopting a single-hull ‘teardrop’ or Alba-core design, the external form of the S-80A has been optimised to reduce self-noise. “The hullform has been subject to exten-sive modelling, simulation and testing to prove its fl ow self-noise characteristics,” reports Mauricio Alvarez Ortiz, Navantia’s S-80 programme manager. “This has inc-luded tow tank testing [at SSPA in Goth-enburg, Sweden] to validate the hydro-dynamic characteristics. Tow tank test also proved the design of the skew-bladed fi xed-pitch propeller.”

The decision to go for a conventional cru-ciform rudder confi guration, rather than an X-form arrangement, was the subject of signifi cant analysis and debate within the design team. “We looked very hard at an X-form design,” Alvarez says, “and acknow-ledge that it offers some advantages in manoeuvring and control.”

But in the fi nal analysis it was the better intrinsic safety of the classic cruciform arr angement that convinced Navantia. “In the event of a control system failure, the cruciform surfaces can be operated effec-tively with just two sticks,” Alvarez says. “Manual operation of an X-form rudder is far more diffi cult in the manual rever-sionary condition.”

He points out that safety and survivabil-ity have been given a high priority in the design philosophy. “We have sought a greater safety operating envelope than oth-er submarines, and have specifi ed a high level of emergency recoverability. This can be attributed to the excellent performance of both the aft hydroplanes and the emer-gency ballast tank blowing system.”

According to Alvarez, the excellent depth-plane control performance accorded by the S-80A will mean no limitations in speed with depth. Furthermore, the boat will be highly responsive, “being able to perform a ‘crash stop’ in less than 80 seconds or fi ve lengths, and able to dive from periscope depth to 100 m [assuming a speed of 5 kt while ‘snorting’] in just 50 seconds”.

Modelling of depth-keeping at periscope depth suggests no snort mast immersions or

S-80A general arrangement.

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sail emergencies while snorkelling in cond-itions up to Sea State 6. Control speed, using the ‘Chinese’ effect of the hydroplanes, is just 2.8 kt. “Most submarines struggle to go at less than 4 kt,” says Alvarez, “so the S-80A will benefi t from enhanced manoeu-vrability — something that is very important while operating in shallow-water conditions — and reduced noise.”

In seeking to minimise vulnerability and achieve maximum stealth, Navantia has con-ducted extensive signature studies looking at the widest possible range of acoustic and non-acoustic infl uences, the latter inc luding magnetic, electrostatic, ELFE (extra-low fre-quency electric), radar, pressure, wake and visual. “The combat system has been de-signed to be fi tted in a noise-optimised plat-form,” remarks Alvarez. “Our self-noise cal-culations are now being used to optimise the positioning of the sonar arrays on the hull.”

Signifi cant attention has also been paid to minimising target echo strength. At this stage the Spanish Navy has decided not to fi t anechoic tiling, “although the option remains for their fi tting at a later date should requirements dictate”, Alvarez says.

Machinery, selected for inherent low vib-ration and airborne noise characteristics, will be fi tted on shock/noise mounts and then grouped on fl oating rafts in the pres-sure hull. Flexible couplings are employed to ensure that equipment and systems are isolated from the hull. Other signature re-duction measures include a diesel exhaust gas diffuser (to suppress thermal and noise

emissions) and the selective application of radar-absorbent material around the masts.

The pressure hull structure itself will be formed from HLES 80 steel, the same mat-erial as used for Scorpene. “Finite element models were used to calculate collapse pres-sure, their predictions then being validated by the manufacture of a sub-scale [6.8 m length and 1.46 m diameter] pressure hull model,” says Alvarez. “This was used to test the real pressure of collapse in as-built conditions.”

Manufacture of the fore and aft pressure domes for the fi rst two boats has been out-sourced to BAE Systems Submarine Solu-tions in Barrow, UK. “Each dome has a large number of penetrations,” explains Alvarez, “and we decided to fi nd a specialist subcon-tractor for these structures. The domes for boats three and four will be partly assembled in Barrow then completed in Cartagena.”

Navantia has, under the terms of a frame-work contract, accessed specialist technical advice and design assurance from UK sci-ence and technology group QinetiQ. This has included support in the areas of hydro-dynamics, structures, shock, signatures, vul-nerability and towed-array handling.

Platform and propulsionThe propulsion plant developed for the S-80A is a hybrid arrangement of classic diesel-electric (combining three 1,200 kW-rated Navantia MTU 16 V 396 SE 84L – GB31L diesel alternator rectifi er sets and two 180-cell groups of Tudor batteries) and

a 300 kW AIP system based on reformed ethanol and liquid oxygen. The latter sys-tem, seen as one of the S-80A’s principal performance discriminators, is being devel-oped by Navantia in conjunction with UTC Power and Hynergreen, with a land-based test site to be built at Cartagena to prove the system and allow for an evaluation of long-endurance performance.

“UTC is, we believe, the best in the world in this area,” says Alvarez. “They are the pioneers in fuel-cell technology, with over 40 years’ experience and a range of expertise in different fuel-cell types. The open anode proton exchange membrane technology we will use is unique to UTC, and represents the very best technology available today.”

The full AIP system will be accommo-dated in a 7.89 m section in the centre part of the boat. This will be split horizon-tally into two separate compartments: the fuel-cell system, bio-ethanol proces-sor, power-conditioning system, CO2 dis-posal system and auxiliaries on an upper deck; and the liquid oxygen tank fi tted in a lower compartment.

Navantia is confi dent it can deliver the Spanish Navy’s requirement for an AIP sol-ution providing an endurance of 15 days at 4 kt (assuming a nominal 110 kW hotel load). “If you can switch off non-essential power consumers and reduce hotel load to 50 kW, then endurance could be extended to 20 days,” says Alvarez. “Alternatively, a submarine on the bottom could conserve


power, and therefore prolong its sub-merged endurance, by removing the pro-pulsion load.”

Installed power is put to work by a 3,500 kW synchronous AC permanent magnet motor driving a single shaft. “We have sourced this from Gamesa Cantarey in Cantabria,” says Alvarez. “Their design [a prototype of which has already undergone successful testing] is based on four three-phase semi-motors and features IGBT [insulated gate bipolar transistor] power electronics con-trolled by pulse-wave modulation.

“It is lightweight, compact, quadruple-redundant and offers shock performance double that of the competition,” says Alva-rez. “And, importantly for safety, it can continue operating in the event of a cooling system failure.”

Although Navantia’s Faba Systems div-ision is long established as a supplier of IPMS systems for surface ships, the S-80A

programme will see the fi rst implemen tation of a submarine IPMS by the company. Op-erated from two Sainsel-supplied CONAM consoles, this highly automated Sistema de Control de Platforma (SCP) will control and monitor equipment throughout the vessel, taking signals from the propulsion plant, AIP system, auxil iaries, safety sys-tems, steering station and combat system. Local service stations distributed around the submarine will collect and transmit sig-nals over the SCP network.

A damage-control system is embedded in the SCP. Other functionality includes condition-based monitoring and diagnos-tics, and onboard training.

Faba acknowledges that the biggest chal-lenge in the development of the S-80A’s SCP is the safety-critical nature of the system. Accordingly, a land-based test and reference system is about to start building at Faba’s Cartagena facility to support

development and provide a high-fi delity test and simulation environment.

Italy’s Avio SpA is supplying its GAUDI (Guidance Automation Unit Distributed Int -elligence) steering-control system to Faba Systems for the S-80A programme. Based on a distributed architecture, GAUDI is claimed by its manufacturer to offer greater fl exibility, survivability and reliability than more conventional centralised systems.

Combat core One of the most critical and contentious decisions in the formative years of the S-80A programme was that concerning the archi-tecture of the combat system core. Following a protracted evaluation of competing solu-tions, culminating in a face-off between US rivals Lockheed Martin and Raytheon, the former was in 2005 selected to partner Faba Systems in the design, development and inte-gration of a fully integrated combat system core that included a multi-array sonar suite and associated processing functionality, a com mand-and-control subsystem and a weapon-control subsystem.

The adoption of an open-system archi-tecture, leveraging commercial off-the-shelf technology already proven on the US Navy’s Virginia- and Los Angeles-class SSNs, is intrinsic to the combat management and weapon-control system and its associated integrated sonar suite, says Ramón Andréu, Navantia’s S-80A combat system manager. “What we are getting is in many respects a scaled version of the system going aboard the Virginia class,” he says. “It will also enable the S-80A to keep pace with the int-roduction of new technology and capabili-ties for enhanced performance and greatly reduced cost over the life of the platform.”

At the heart of the S-80A combat system are seven Sainsel CONAM SUB multi-function common consoles. “The mantra is ‘any function, any console’,” says And-réu. “Each will be capable of processing and displaying sensor data, or alternatively employed for tactical functions such as track management, weapon planning and weapon control.”

He continues: “The fi rst CONAM SUB shipsets are due for delivery from Sainsel by the end of 2007. Seven consoles will go to the Lockheed Martin land-based test site in Manassas [Virginia], with an-other seven going to Faba to populate their combat system core land-based test site in San Fernando.”

A multi-array integrated sonar system supplied by Lockheed Martin (EDO has been subcontracted to manufacture the sonar outboard elements) features cylind-rical, passive-ranging, wide-aperture fl ank, acoustic intercept, and mine- and obstacle-det ection arrays, together with an own-noise monitoring system. Also integrated into the sonar suite is the indigenous SAES Solarsub low-frequency towed-array sonar (for which QinetiQ is managing the acquisition of a reelable handling system).

As regards above-water sensors, the S-80A is specifi ed with a comprehensive suite comprising optronics, electronic sup-

The S-80A will be delivered ‘Tomahawk-ready’, according to Navantia. Weapons already earmarked include the DM2A4 heavyweight torpedo and the Sub-Harpoon anti-ship missile.

(Above) S-80A mast arrangement.

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RELATED ARTICLES:● Submarine forces, juws.janes.com, 18.10.07● Spanish order for submarine pressure hull domes comes to UK, jni.janes.com, 02.05.07● DCN, Navantia face split over submarine designs, jdw.janes.com, 31.10.06● Pegaso to protect S-80A submarines, jdw.janes.com, 27.07.06


port measures (ESM), a low-probability-of-intercept (LPI) radar, IFF (identifi cation friend-or-foe) and AIS (automatic ident i -fi cation system). These pieces of equip ment, together with communications antennas, will be raised using universal modular masts supplied by Calzoni.

Having considered the option of specify-ing two non-hull-penetrating optronic masts, the Spanish Navy has opted for a more conservative approach that will see the S-80A fi tted with a conventional attack periscope (incorporating a thermal imager and low-light TV) alongside a non-hull-penetrating surveillance mast (combining a high-defi nition TV, a colour camera, a ther-mal imager and a laser rangefi nder). Koll-morgen Electro-Optical has been contrac-ted to supply both pieces of equipment (des ignated Model 2010 AP and Model 2010 OS), with Indra providing its MVT 640 3–5 µm thermal imager for both.

The Pegaso ESM suite is a home-grown product from Indra based on wideband digital receiver technology, combining func-tionality for radar and communications band intercept and analysis. According to Andréu: “The system features two separate antennas: a main omnidirectional/direc-tion-fi nding antenna on the dedicated ESM mast, and a secondary antenna atop the optronic mast.

“Indra is also responsible for supplying an IFF transponder [the TXP-25 Mk XIIA supporting Mode 5/S] and a navigation and surface surveillance radar in the shape

of its ARIES-S LPI radar,” Andréu adds. Part of the ARIES family of frequency-modulated continuous-wave LPI radars, the ARIES-S variant has been designed to fi t in a non-hull-penetrating architecture, with the transmitter/receiver unit sized for installation inside a submarine mast.

The integrated communication system specifi ed for S-80A by Faba Systems will be based around an EID ICCS-5 commu-nications control system and Rohde & Schwarz radio equipment. Antenna sub-systems are being furnished by Aeromari-time, Nereides, Dowding and Mills and Calzoni. Indra is supplying an SHF satel-lite communications terminal, thought to be a derivative of the company’s TSUB sat-com equipment. Andréu also notes that S-80A “will be Link 22-enabled”, with Spanish company Tecnobit supplying the data link processor terminal.

FirepowerWeir Strachan & Henshaw is supplying the weapon-handling and discharge system (WHDS) for the S-80A programme. Com-prising six torpedo tubes with positive air discharge provided by two rotary air-tur-bine pumps, the WHDS will be able to host and launch torpedoes, mines and missiles.

Weapons already earmarked for the S-80A submarine comprise the Atlas Elektronik DM2A4 electrically powered heavy weight wire-guided torpedo; the Boeing Sub-Harpoon anti-ship missile; and the SAES

Mincoa multi-infl uence mine. One specifi c feature of the WHDS is

the ability to automatically eject mines in sequence, using all six torpedo tubes in alt-ernation. Furthermore, says Alvarez, the WHDS has been designed to be ‘Toma-hawk-ready’. “We have been provided with all the information necessary to ensure that the structures, handling system and braces are all fully prepared to take the weapon. Provision has also been made in the design — in terms of space, power and interfaces — for the associated control hardware in the weapon compartment.”

As well as the WHDS, Weir Strachan & Henshaw is supplying a countermeasures ejector system for the S-80A programme. A total of 20 ejectors are fi tted under the submarine casing aft of the fi n, with space reserved forward for a further 10 systems.

Alongside its standard complement of 32 crew members, the S-80A will have perm-anent accommodation for a force of eight special forces personnel. A lock-in/lock-out hatch is fi tted for the egress and entry of special forces divers. ■

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S-80A