India's 3rd Scorpene-class submarine "Karanj" launched

The third indigenously-built diesel-electric Scorpene-class submarine, ‘Karanj’, was launched at the Mazagon Dock Shipbuilders Ltd (MDL) here on Wednesday morning by Reena Lanba, wife of Indian Navy chief Admiral Sunil Lanba.

Another three Scorpenes, being built by MDL in collaboration with DCNS of France under a Transfer-of-Technology contract, are in the pipeline.

The first of the vessels, INS Kalvari, was commissioned into the Indian Navy on December 14, 2017 while the second, ‘Kandhari’, was launched in January of that year and is undergoing sea trials.

Admiral Lanba said the launch of ‘Karanj’ marked a significant departure from the manning and training philosophy adopted for the first two submarines, adding that from now onwards the Navy would be fully self-reliant in the training and certification processes.

The previous INS Karanj served the nation for 34 years until 2003 and also participated in the 1971 war, he added.

The state-of-the-art technology utilised for constructing the Scorpene class submarines has ensured superior stealth features such as advanced acoustic silencing techniques, low radiated noise levels, hydro-dynamically optimised shape and the ability to launch a crippling attack on the enemy using precision guided weapons.

The attack can be launched with both torpedoes and tube launched anti-ship missiles, while underwater or on surface. The stealth of this potent platform is enhanced by the special attention given to various signatures.

These stealth features give it an invulnerability, unmatched by most submarines.

A sophisticated and state-of-the-art Shore Integration Facility has been developed at MDL for integration and simulation of various equipment of the Scorpene submarine combat system for which there was no facility available in the country.

However, in a setback to the programme, the indigenous AIP will not be incorporated in vessels five and six as originally planned but retrofitted on all six boats at a later stage.

Air Independent Propulsion (AIP), being developed by the Maharashtra-based Naval Materials Research Laboratory (NMRL), is a fuel cell that replaces diesel in the conventional submarines.

With this system, a conventional submarine that needs to surface every three to four days for oxygen can stay under water for up to two weeks.

The attacks can be carried out with torpedoes both while submerged or on the surface — in all war theatres including the tropics, giving it an unmatched invulnerability.

The ‘Karanj’ submarine has an overall length of 67.5 metre and a height of about 12.3 metre. The hull form, fin and hydroplanes are specifically designed to produce minimum underwater resistance.

A sophisticated and state-of-the-art Shore Integration Facility has been developed at MDL for integration and simulation of various equipments of the Scorpene submarine combat system for which there was no facility available in the country.

As part of the efforts to reduce the construction timeline, the MDL completed the critical sub-section fabrication of the pressure hull for all six submarines 11 months before the PERT date.

Further time taken to complete the fabrication of the 16 sub-sections of a submarine came down from 39 months in Boat 1 to 20 months in Boat 2 and this time frame of 20 months has been accepted by the French collaborators as higher than their standards.

Also due to stringent monitoring and proactive resolution of problems, the number of defects found during fabrication of sub-sections fell from 165 in Boat 1 to just 14 in Boat 6, said an MDL official.