The S-81 submarine is now afloat and ready to begin in-port trials

It was christened "Isaac Peral" by the Princess of Asturias 15 days ago and must now begin to demonstrate its nautical and operational capabilities
PHOTO/Navantia - El nuevo submarino S-81 fue puesto a flote el 7 de mayo  desde  un dique flotante de 90 metros de longitud. Ahora comenzará la fase técnica de las pruebas en puerto

PHOTO/Navantia  -   The new S-81 submarine was launched on 7 May from a 90-metre-long floating dock. The technical phase of in-port testing will now begin

The S-81 submarine "Isaac Peral" has already had its baptism at sea and is now safely berthed at one of the docks of Navantia's Cartagena shipyard. 

Once in the water, the first submarine of Spanish design and manufacture will undergo the first technical phase of the so-called "port tests". These are aimed at checking the general condition of all the systems on board, charging its batteries and filling its fuel tanks in order to be able to carry out the initial propulsion tests with the submarine moored.

PHOTO/MDE - Las maniobras para su puesta a flote contaron con la presencia de la secretaría de Estado de Defensa, Esperanza Casteleiro. En la imagen, junto con el Jefe de Apoyo Logístico de la Armada, almirante Aniceto Rosique, y el Jefe del Arsenal de Cartagena, vicealmirante Pedro Luis de la Puente
PHOTO/MDE - The manoeuvres for its launch were attended by the Secretary of State for Defence, Esperanza Casteleiro. In the picture, together with the Chief of Logistical Support of the Navy, Admiral Aniceto Rosique, and the Chief of the Cartagena Arsenal, Vice Admiral Pedro Luis de la Puente.

In the presence of the programme inspectors, the three diesel-electric generators of the propulsion system will be started up one by one, who will check that the electrical distribution system works in all cases according to the predefined standards. On subsequent days, the full battery charging tests will be repeated and the performance of the electric motor will be verified.

The technical tests in port involve a series of phases that should confirm that all systems and equipment on board are functioning correctly and optimally. If not, the anomalies detected will be corrected and the necessary adjustments and modifications will be carried out, all of which will continue until the first quarter of 2022.

Once all the technical verifications have been passed, "it will be then that the S-81 will be considered seaworthy and the sea trials will begin," confirmed engineers familiar with the details of the process.

PHOTO/Navantia - Con el comandante y la dotación de quilla a bordo del “Isaac Peral”, el casco del nuevo submarino entra en contacto con el agua del Mediterráneo
PHOTO/Navantia - With the commander and keel crew on board the "Isaac Peral", the hull of the new submarine comes into contact with the water of the Mediterranean.
Sea trials in 2022

These sea trials comprise an exhaustive surface navigation campaign of about 10 knots (18.5 km/h) and diving at 19 knots (35 km/h) to a maximum depth of about 300 metres, although the exact maximum operational depth is a matter of secrecy. The tests of its nautical and operational capabilities should be completed one year later, with the official delivery of the S-81 to the Spanish Navy and its entry into service in the second half of 2023.

The manoeuvres and work that concluded with the launching of the submersible in Mediterranean waters and its subsequent mooring in port culminated at around 19:00 hours on Friday, 7 May. They had begun two days earlier, when the "Isaac Peral" - with a length of 80.8 metres - was placed on a 90-metre-long floating dock, which was moved to an area of the dock at the Cartagena shipyard with the necessary draught to be flooded.

PHOTO/Navantia - La forma y dimensiones de la hélice del S-81 son un elemento clave que define sus prestaciones y le diferencia del resto de submarinos. Por tal motivo, una protección la mantiene oculta de las vistas
PHOTO/FBX - The shape and dimensions of the S-81's propeller are a key element that defines its performance and differentiates it from other submarines. For this reason, it is concealed from view by a guard.

With the commander and keel crew on board the "Isaac Peral" to monitor the progress of the operations, the floating dock flooded its ballast and the hull of the first S-80 class submarine began to be bathed in water and, little by little, to float on its own.

The operation concluded with the intervention of three tugboats, which pushed the submarine from its position in the dock to the quay, where personnel from the Tren Naval del Arsenal de Cartagena proceeded to moor it.

Given the importance of the operation, the launching manoeuvres were carried out under the watchful eye of the Secretary of State for Defence, Esperanza Casteleiro, who was accompanied by the President of Navantia, Ricardo Domínguez, the Head of Logistical Support of the Navy, Admiral Aniceto Rosique, and the Head of the Cartagena Arsenal, Vice Admiral Pedro Luis de la Puente.

A product also designed for export

The shape and dimensions of the S-81's propeller are a key element that defines an important part of the submarine's performance and differentiates it from other similar platforms. For this reason, the propeller has been concealed from view by means of an external protection. Once the submarine was in the water, it was positioned with the propeller underwater.

PHOTO/Navantia - A partir de los próximos días comenzará una exhaustiva campaña de comprobaciones en puerto que se prolongará hasta principios de 2022, en que se dará paso a las pruebas de mar
PHOTO/Navantia - An exhaustive campaign of in-port checks will begin in the next few days and will continue until the beginning of 2022, when sea trials will begin.

In the presence of King Felipe VI, the S-81 was christened "Isaac Peral" by the Princess of Asturias in a military ceremony held on 22 April at the Cartagena factory of the national shipyard Navantia.

Specialising in the construction of submarines, the Navantia factory in Cartagena is working at full speed on the S-82 "Narciso Monturiol", the S-83 "Cosme García" and the S-84 "Mateo García de los Reyes", developed with new silent air independent propulsion (AIP) technologies to replace the S-70 class submersibles, of which there are only two units left. 

Navantia is confident that the new S-80 class and its possible derivatives will become one of its weapons systems with real export capacity, capable of competing in the global market with the non-nuclear ocean-going submarines developed by other countries.

Its first international challenge is in Asia, in the competition that the government of New Delhi has launched to make Project 75 a reality, with which the Indian Navy wants to renew its fleet of non-nuclear propulsion submarines.