Tag Archives: Scorpene-class submarine

Sea Trial of Kalvari

«Kalvari», the first of the Scorpene-class submarines, being built at the Mazagon Dock Shipbuilders Ltd Mumbai (MDL), went to sea for the first time on 01 May 2016. The submarine sailed out at about 1000 hrs under her own propulsion for the first sea trial, off the Mumbai coast and during the sortie. A number of preliminary tests on the propulsion system, Auxiliary Equipment and Systems, Navigation Aids, Communication Equipment and Steering gear. Various Standard Operating Procedures were also validated for this new class of submarines. The submarine then returned to harbor in the evening.

The Kalvari class is a class of submarines based on the Scorpene-class submarine being built for the Indian Navy
The Kalvari class is a class of submarines based on the Scorpene-class submarine being built for the Indian Navy

This important milestone was achieved by MDL after overcoming a number of challenges faced since launching of the submarine last year in October. During the next few months, the submarine will undergo a barrage of sea trials, including surface trials, diving trials, weapon trials, Noise trials etc., which would test the submarine to the extremes of its intended operating envelop. Thereafter she would be commissioned into the Indian Navy as INS Kalvari (S50) later this year. Commissioning of Kalvari will be a re-affirmation of India’s capability to build submarines and a major boost for the «Make in India» programme of the government.

In April last year, the Hon’ble Raksha Mantri had visited MDL and directed that all-out effort be made to complete the project in time. Accordingly, the teams from MDL, Indian Navy and DCNS have been working round the clock. On 01 May, with the first sea sortie of Kalvari, MDL has achieved a major project milestone.

Leveraging on the experience and the transfer-of-technology of the Scorpene project, and with the enhanced and upgraded infrastructure, MDL is ready for undertaking future submarine and shipbuilding projects, in order to meet the growing requirements of National Security.



India joined the exclusive group of submarine constructing nations on 07 February 1992, with the commissioning of the first Indian built submarine, INS Shalki (S46). That was indeed a proud day for Mazagon Dock Shipbuilders Ltd, who had built this submarine. Mazagon Dock then went on to commission another submarine, INS Shankul (S47), on 28 May 1994. These submarines are still in service today, after more than 20 years; testimony to the skills and capability of Mazagon Dock.

The ongoing project for the construction of six Scorpene-class submarines, has M/s DCNS of France, as Collaborator and includes «Transfer of Technology», with M/s MDL as the «Builder».


Operational Features

The state-of-art features of the Scorpene include superior stealth and the ability to launch a crippling attack on the enemy using precision guided weapons. The attack can be launched with torpedoes, as well as tube launched anti-ship missiles, whilst underwater or on surface. The Stealth features give it invulnerability, unmatched by many submarines.

The Scorpene Submarine is designed to operate in all theatres including the Tropics. All means and communications are provided to ensure interoperability with other components of a Naval Task Force. It can undertake multifarious types of missions typically undertaken by any modern submarine i.e. Anti-Surface Warfare (ASuW), Anti-Submarine Warfare (ASW), Intelligence gathering, Mine Laying, Area Surveillance etc.


Construction Features

Submarines are built from special steel, capable of withstanding high yield stress and having high tensile strength, thereby allowing them to withstand high hydrostatic force and enabling them to dive deeper to further enhance stealth.

The Submarine is built according to the principle of Modular Construction, which involves dividing the submarine into a number of sections and building them parallelly. The equipment is mounted onto Cradles and then embarked into the sections. The complexity of the task increases exponentially as it involves laying of around 60 km of cabling and 11 km of piping in extremely congested and limited space inside the submarine. Further, the stringent tolerances laid down for the construction of the Scorpene were indeed a challenge, but have been successfully achieved.


Other Features

The Scorpene is equipped with Weapons Launching Tubes (WLT), and can carry weapons on board which can be easily reloaded at sea, through special handling and loading equipment. The array of weapons and complex sensors fitted on board the Scorpene are managed by a high technology Combat Management System, which integrates various diverse systems fitted onboard into One Formidable Whole.


Status of Submarine

The submarine was undocked on pontoon on 06 April 2015 in the presence of Hon’ble Raksha Mantri Shri Manohar Parrikar. After completing the important milestones of vacuum test and battery loading, the submarine was launched at the Naval Dockyard on 28 October 2015 and thereafter brought back to MDL for completion of the Basin trials and Harbour Acceptance trials phase.

After conquering numerous challenges faced during the «Setting to Work» phase and undergoing rigorous harbour tests & trials to the complete satisfaction of the customer, the submarine is now fully ready to undergo for sea trials.


«Kalvari»: The Tiger Shark

Kalvari is the dreaded Tiger Shark, a deadly deep sea predator. As is the tradition, ships and submarines of the Navy, are brought alive after decommissioning. The first Kalvari, which was also the first Indian submarine, was commissioned into the Indian Navy on 08 December 1967. She was decommissioned on 31 May 1996 after almost 30 years of yeoman service to the nation. In true nautical traditions, she will now be re-incarnated, by Mazagon Dock, once again a powerful predator of the deep, guarding the vast maritime interests and areas of our nation.

The commissioning of Yard 11875 (Kalvari), will not only mark a generational shift in technology, insofar as submarine construction in India is concerned, but also for submarine operations by the Indian Navy.


Contribution to National Security and Nation Building

With its history of constructing the Leander and Godavari class Frigates, Khukri class Corvettes, Delhi and Kolkata class Destroyers, Shivalik class Stealth Frigates, 1241 RE Missile Boats and the Shalki class submarines, there is now no doubt that MDL has deservedly earned the soubriquet «Warship and Submarine Builders to the Nation».

MDL’s contribution to national security and nation building will continue with the P-15B class destroyers, the first of which was launched in April 2015, and the P-17A class stealth frigates, the follow-on of the P-17 Stealth Frigates.