Kolkata-class destroyer

The Kolkata-class (Project 15A) are a class of guided-missile destroyers constructed for the Indian Navy. The class comprises three ships - Kolkata, Kochi and Chennai, all of which are being built by Mazagon Dock Limited (MDL) in India, and are the largest destroyers to be operated by the Indian navy. Due to delays in their construction, and a problem found during the sea trials, the initial commissioning date of the first ship of the class has been pushed back from 2010 to 2014.

The destroyers are a follow-on of the Project 15 Delhi-class destroyers, but are considerably more capable due to major improvements in the design, the addition of substantial land-attack capabilities, and the fitting-out of modern sensors and weapons systems. An even more enhanced version of the Kolkata-class - Project 15B - has been approved. Project 15B destroyers will feature enhanced stealth characteristics as well as incorporating state of the art weaponry and sensors including the extended range Barak surface-to-air missiles.

Development
In 1986, the Cabinet Committee on Political Affairs (CCPA) approved a follow-on class of the earlier Project 15 Delhi-class destroyers. The aim was that the follow-on class would incorporate a higher level of air-defence, land attack, anti-submarine and anti-ship capabilities than the preceding class. However, the Indian Navy did not initially take up the option. By the year 2000, the Indian Navy had redesigned the follow-on Kolkata-class to incorporate even higher levels of technology - including modern stealth characteristics and in May of that year, approval for the construction was given. Concept and function for Project 15A was framed by the navy's Directorate of Naval Design, while the detailed design was developed by Mazagon Dock Limited (MDL).

Construction


Construction of three Kolkata-class ships was sanctioned by the Government of India in May 2000, and steel for the lead ship was cut in March 2003. Construction began in September 2003 at Mazagon Docks, Mumbai, with an initial expectation that the first of the class would be handed over to the navy by 2010. However, since then the Kolkata-class has suffered consecutive delays, slow construction procedures and technical problems which will now see the first of the class now enter service during early 2014. The delays in the construction programme have been attributed to - persistent design changes made by the Indian Navy to incorporate new weapons systems and sensors, failure by a Ukrainian shipyard to deliver the ship's propellers and shafts and the contract later being awarded to a Russian firm, and finally the delay in the delivery of the Barak 8 anti-air missiles, which are still in the final stages of completion with Israel Aerospace Industries and the Defence Research and Development Organisation.

The Kolkata-class are the largest destroyers ever to be constructed at Mazagon Docks, and as of 2013, all three ships of the class have been launched and are being fitted out. Technical problems were found during the sea trials of the lead ship Kolkata, which delayed the project by six months to early 2014.

Project 15B
In January 2011, the Cabinet Committee on Security gave approval for a follow-on order of four more destroyers under Project 15B. Project 15B will retain the same hull as 15A Kolkata-class destroyers, but there will be significant changes in the superstructure that will improve the ships stealth characteristics (flush deck), include better sound and infrared suppression systems and more sophisticated weaponry such as: Nirbhay land-attack cruise missiles, hypersonic BrahMos-II anti-ship missiles and Barak 8-ER SAMs. They will operate two helicopters, and are expected to displace approximately 8,000 tonnes at full displacement (1200 tonnes more than 15A). Russia's Baltic Shipyard has been contracted to provide four sets of line shafts by 2017. Saint Petersburg's Northern Design Bureau was consulted during the design phase.

The total cost of the project is expected to be inr 300000000000. Build-time for Project 15B is expected to be shorter than 15A, as no major re-designing would be done and would require only one and a half years of planning. Due to this, each warship is expected to save US$ 1 billion in costs. After finalisation of design, the first destroyer is expected within four years, with the others delivered at annual intervals, starting from 2018.

Design and description
The Kolkata-class share similar dimensions to the previous Dehli-class, however with a standard displacement of 6,250 t and a full-load displacement of 6,800 t, they are the largest destroyers ever operated by the Indian Navy. These are the first stealth destroyers being built by India and marked a significant development in India's shipbuilding technology. The ships would incorporate modern weapons and sensors, and will have an advanced information warfare suite, an auxiliary control system with a sophisticated power distribution architecture, and modular crew quarters.

The class have a length of 163 m, a beam of 17.4 m and a draft of 6.5 m. The ship's power and propulsion features a standard Combined gas and gas system utilizing twin Zorya M36E gas turbine plants and four DT-59 reversible gas turbines. The class also features two KVM diesel engines. On-board Wartsila WCM-1000 generators and Kirloskar AC generators supply the ship's electricity. The two propellers are run via two RG-54 gearboxes. This configuration allows the ship to reach speeds in excess of 30 kn. Aviation facilities include a large flight deck and an enclosed hangar for up to two maritime helicopters.

The class is equipped with Thales LW-08 long range volume search radar, EL/M-2248 MF-STAR multi-mission AESA radar and EL/M-2238 S-band STAR surveillance radar from Israel Aerospace Industries. A Nagin active towed array sonar and a HUMSA-NG (hull-mounted sonar array - new generation) are carried for sub-surface surveillance. To protect against anti-ship missiles coming from multiple directions, the ship carries the Elbit Systems Deseaver MK-II decoy control and launching system.

The ship's main air-defence armament is composed of four 16-cell vertical launching systems (VLS) allowing for a combination of up to 64 Barak 1 (short-range) and Barak 8 (medium-range) air-defence missiles. A typical load-out for-example may consist of 48 Barak-8 missiles and 16 Barak-1 missiles. In addition, four AK-630 CIWS are fitted for close-in defence. The supersonic BrahMos anti-ship and land-attack missiles are the primary offensive armament of the Kolkata-class. The BrahMos missiles are fitted into a 16-cell Universal Vertical Launcher Module (UVLM) allowing one missile per launch silo. Perhaps the most distinctive and noticeable armament of the Kolkata-class is its 130 mm naval gun located forward of the bridge. The 130 mm gun provides limited anti-shipping capability in addition to its naval gun fire-support role for land based operations. For anti-submarine warfare, the Kolkata-class are equipped with a torpedo launching system via four torpedo tubes and two RBU-6000 anti-submarine rocket launchers.

Ships of the class
Initially in 2008, each vessel and its long-term spare parts was expected to cost inr 38000000000, but the ship's construction costs escalated over 225% during the course of their build, and by 2011, cost of each warship became inr 116620000000. The rising costs were the source of much controversy at the time, and the Defense Minister A. K. Antony cited the causes being the delay in supply of warship-grade steel by Russia, increase in costs of Russian specialists due to inflation during the build period, wage revision due from October 2003 and delay in finalisation of cost of weapons and sensors.