INS Nistar’s deep-sea rescue capabilities reinforce India’s role as region’s ‘preferred security partner’

INS Nistar, the first indigenously designed and constructed diving support vessel, was commissioned into the Indian Navy on Friday. The ship, which is the first of the two diving support vessels being built by Hindustan Shipyard Limited, is designed to undertake complex deep-sea saturation diving and rescue operations – a capability only a few navies possess across the globe.

INS Nistar and its sister ship INS Nipun — which is expected to be commissioned later this year — are designed to carry a Deep Submergence Rescue Vehicle (DSRV) that is capable of rescuing personnel stuck underwater on stricken submarines.

Both the ships are equipped with state-of-the-art diving equipment such as remotely operated vehicles, self-propelled hyperbaric lifeboat and diving compression chambers. They can undertake diving and salvage operations up to a depth of 300 meters.

They will also serve as the ‘mother ship’ for the DSRV to rescue and evacuate personnel from a submarine in distress well below the surface.

The ships will significantly enhance the Indian Navy’s operational and strategic capabilities and also have the potential of their services being availed by other countries in case of any contingency or for training.

Speaking at the commissioning ceremony, the Minister of State for Defence, Sanjay Seth, said that the induction of INS Nistar firmly reinforces the role of the Indian Navy as the ‘first responder’ and ‘preferred security partner’ in the region.

Chief of the Naval Staff, Admiral Dinesh K Tripathi, termed INS Nistar as not just a technological asset, but a crucial operational enabler that will provide critical submarine rescue support to the Indian Navy as well as our regional partners. This will enable India to emerge as a ‘Preferred Submarine Rescue Partner’ in this region.

A DSRV is a specialised submersible designed to rescue personnel from disabled submarines. It’s a crucial part of a submarine rescue system and is equipped with various tools like sonar for locating submarines, remotely operated vehicles for inspections and assistance and a submarine rescue vessel for direct crew transfer after mating with the distressed vessel. The DSRV can also provide emergency supplies and medical support.

The Indian Navy already has two DSRV systems, one for the western fleet and the other for the eastern fleet, which were procured from the United Kingdom in 2018 and 2019 and can operate up to a depth of 650 meters. These will now be deployed onboard the two Nistar Class boats.

In 2021, the Indian Navy had deployed one of its DSRVs to assist the Indonesian Navy in search and rescue efforts for the Indonesian submarine, KRI Nanggala, which had gone missing during a torpedo training exercise near Bali. The submarine was later found on the sea bed broken into three pieces with all 53 crew dead.

In September 2018, Visakhapatnam-based public sector undertaking Hindustan Shipyard Limited (HSL) had signed a contract with the Indian Navy to indigenously design, develop and manufacture two Nistar Class ships, with deliveries initially scheduled for 2023. About 120 MSMEs were involved in the design and construction, with 80 per cent of the content being indigenous.

With a displacement of more than 10,000 tons, these ships are heavier than the Indian Navy’s largest destroyers like the INS Visakhapatnam and INS Kolkata. These are lightly armed with two 30 mm AK-630 close-in weapon systems for self-defence but are equipped with advanced electronics warfare and navigation suites and also have the capability to carry a utility helicopter.

The deep-sea saturation diving that these ships will support is a specialised form of sub-surface operations that allows divers to work at great depths for extended periods by remaining in a pressurised environment.

Divers stay in a pressurised chamber, often on a support vessel, which is maintained at a pressure equivalent to that at the underwater depth where they would be working. This saturation allows them to make multiple dives without needing to decompress after each one, which is crucial for deep-sea work.

INS Nistar is not the first ship by this name to serve with the Indian Navy. After India began inducting submarines in 1969, the need for possessing credible capability for rescue of submariners also rose.

For this, INS Amba, a submarine depot ship, was procured from Russia and in March 1971, INS Nistar was acquired from Russian reserves. The old Nistar was capable of sending a module called Bell —which carried divers — and mating it with escape hatches on submarines. Thereafter, the crew could be rescued in batches of eight.

It was also designed to train deep-sea divers to the level of saturation diving and enabled the Indian Navy to create a special diving cadre that ultimately led to the raising of marine commandos and clearance divers capable of carrying out special missions and covert operations.

India