S-81 Isaac Peral is one of the largest non-nuclear submarines in the world. The long-range 2,965 ton boat will bring new capabilities to the Spanish Navy and is being offered on the export market. Uniquely for a Western non-nuclear submarine it is equipped to launch Tomahawk missiles.
H I Sutton 22 Apr 2021
On a sober day, as the submarine community awaits news of the missing Indonesian sub, KRI Nanggala, there are submarines elsewhere with more positive stories. New submarines are being launched. The Royal Navy’s fifth Astute Class boat, HMS Anson, has been rolled out in Barrow-in-Furness, UK. And in Spain another new submarine, the first in its class, is being launched by Navantia.
The Spanish Navy’s new submarine, Isaac Peral (S-81), is being christened today in Cartagena, Spain. It is one of the largest non-nuclear submarines in the world and promises to be a major step up for the Spanish Navy (Armada Española).
Its S-80 Plus design will be characterized by its use of a bioethanol fuel cell AIP (air independent power) system. Known as BEST (Bio-Ethanol Stealth Technology) by the submarine’s builder, Navantia, this offers some advantages over other AIP systems. After use the ethanol is reformed which overcomes the need to separately store hydrogen aboard. Other AIP submarines need hydrogen tanks. Additionally, the ethanol is a relatively available fuel to source.
The submarine will be armed with three primary weapons. These are the DM2A4 heavyweight torpedo, UGM-84 Sub-Harpoon anti-ship missile and SAES seabed mines. It was also planned to equip them with the UGM-109 Tomahawk land attack cruise missile. This would place the Spanish Navy in an elite group of submarine operators with a ‘first night’ strategic strike capability. While the Tomahawk order has passed into history, the submarine retains the capability to carry them if they are acquired in the future. This capability is unique among non-nuclear NATO submarines.
About The Name: Isaac Peral
The lead boat’s name harkens back to a time when Spanish engineers were among the first pioneers of submarine warfare. Isaac Peral (1851-1895) was a naval officer and engineer who designed the first all-electric submarine. The craft was commissioned into the Spanish Navy in 1889, more than 10 years before the US Navy and Royal Navy commissioned their first Holland Class submarines.
In his honor, the name Isaac Peral has been given to three more previous submarines of the Spanish Navy. Despite Peral’s pioneering work the Spanish postwar submarine fleet has partly been built from acquired types. Local production of French designs started at Cartagena in the late 1960s with the Daphné-class. Four of these were build, followed by four Agosta Class boats in the 1980s.
In the 1990s Navantia (Spain) and DCNS (Now Naval Group, France) started the joint development of the Scorpène Class submarine. This was aimed at the export market and has been successful with sail to Chile, Malaysia, India and Brazil.
However the design was too small for Spanish requirements and the S-80 submarine program was launched. At this point Navantia and Naval Group parted ways and the S-80 is seen as a Spanish design. Naturally there are some general characteristics of the Scorpène in the design. This is most visible in the sail where the resemblance is clear.
Compared to the Scorpène Class
Compared to the Scorpène the S-80 has a wider hull. The pressure hull diameter is 7.3 meters (24 ft) compared to 6.2 meters (20 ft). This seemingly small difference is enough to allow for an extra deck level. It also means that the same number of torpedoes can be carried but with the torpedo room not taking up the entire height of the forward part of the submarine. Length is also greater at 80.8 meters (232 ft) compared to 61.7 meters (202 ft).
Another major difference is that the S-80 has been designed from the start as an AIP submarine. Currently no Scorpène class boats have AIP although there are plans for them to catch up. French submarine builder Naval Group, who now market the Scorpène exclusively, offer a system. And in India a local AIP system will be retrofitted to the Kalvari Class variant.
The development of the S-80 has not been without complications and delays. The first two boats, Issac Peral (S-81) and Narciso Monturiol (S-82) will enter service without the AI. Instead it will be added during a later overhaul. The third hull, Cosme García (S-83), should have the AIP installed this year. The last boat, Mateo García de los Reyes (S-84) will also receive it during construction.
The new class promises to bring the Spanish Navy’s submarine fleet thoroughly up to date. Most recently the launch of the first boat has been delated due to the COVID-19 pandemic. The AIP has endurance of about 3 weeks and can be operated throughout the entire depth-range of the submarine. Combined with the low crewing requirements, just 32 people, this may make it attractive on the international market. So it may also have some export potential, although it faces tough competition. It is reportedly in the running for India’s next non-nuclear submarine program, the P-75I.
