On 25 August 2026, the Ministry of Defence announced that the Indian Navy will commission Nipun, the second Diving Support Vessel (DSV) of the Nistar-class, on 31 August 2026 at Naval Dockyard, Mumbai. Indigenously designed and constructed by Hindustan Shipyard Limited (HSL), Visakhapatnam, the vessel was delivered to the Navy on 30 July 2026 after an extensive programme of outfitting and trials.
A diving support vessel does not fire missiles, does not carry aircraft, and will never appear in a fleet review photograph as the centrepiece. It is nonetheless one of the more consequential inductions of the year, and the reason is worth understanding rather than memorising.
What the ship is for
Saturation diving. The ordinary limit on deep diving is not depth itself but decompression time. A diver breathing gas at high pressure absorbs inert gas into the tissues, and must ascend slowly enough for it to come out safely. The deeper the dive, the longer the decompression — until the working time at depth becomes trivially short compared with the hours of ascent.
Saturation diving solves this by exploiting a physiological fact: once tissues are fully saturated with inert gas at a given pressure, further time at that pressure adds nothing to the decompression requirement. Divers therefore live for days or weeks in a pressurised chamber aboard the ship, are transferred to the worksite in a diving bell at working pressure, and decompress once, at the end of the whole assignment. This turns a few minutes of useful work into weeks of it. A DSV is essentially a habitat, a lift and a hospital for people working at pressures the human body cannot casually visit.
Submarine rescue. The vessel's most strategically significant role is as a mothership for a Deep Submergence Rescue Vehicle (DSRV) — a small submersible that mates with the escape hatch of a disabled submarine and ferries the crew to the surface under pressure. A submarine that loses propulsion or floods on the seabed has a survivable window measured in days, and the constraint is almost never the rescue vehicle itself; it is how fast the DSRV can reach the site. A DSRV is useless in a warehouse. It needs a purpose-built ship with the handling systems, chambers and medical facilities to deploy it, which is exactly what a DSV provides. India operates a DSRV capability on both coasts, and each needs a mothership.
Underwater intervention and salvage. Beyond rescue: repairing hulls, clearing fouled propellers, recovering equipment, inspecting moorings and supporting remotely operated vehicles (ROVs) for work below the reach of divers.
The class, and the name
INS Nistar, commissioned in July 2025, was the first indigenously designed and constructed Diving Support Vessel of the Indian Navy — a roughly 118-metre, approximately 10,000-tonne ship capable of supporting saturation diving to about 300 metres, with ROVs able to work considerably deeper. It was built with more than 80 per cent indigenous content and the participation of around 120 MSMEs, which is the detail that makes the "self-reliance" claim substantive rather than decorative — indigenisation measured by supplier base rather than by final assembly.
The name carries history. The earlier INS Nistar was a submarine rescue vessel of Soviet origin that served the Indian Navy from the early 1970s, and was associated with salvage and rescue work in that era. Reusing the name for the first indigenous vessel of the type is deliberate. Nistar means deliverance or rescue; Nipun means skilled or adept — both naming choices that describe the function rather than commemorating a place or a person, which is itself unusual in the Indian Navy's conventions.
The shipyard question
Hindustan Shipyard Limited, Visakhapatnam is worth knowing in its own right. It is one of India's oldest shipyards, and it was transferred to the Ministry of Defence in 2010 — a change that turned a struggling commercial yard into a defence production asset.
Keep the defence shipbuilding map straight, because matching yards to ships is a standing NDA question:
| Shipyard | Location | Known for |
|---|---|---|
| Mazagon Dock Shipbuilders (MDL) | Mumbai | Destroyers (Kolkata, Visakhapatnam class), Scorpene submarines |
| Garden Reach Shipbuilders & Engineers (GRSE) | Kolkata | Frigates, corvettes, survey vessels |
| Goa Shipyard Limited (GSL) | Goa | Offshore patrol vessels, Coast Guard ships |
| Cochin Shipyard Limited (CSL) | Kochi | INS Vikrant, India's first indigenous aircraft carrier |
| Hindustan Shipyard Limited (HSL) | Visakhapatnam | Nistar-class DSVs, fleet support ships |
And the naval commands, for orientation: Western at Mumbai, Eastern at Visakhapatnam, Southern at Kochi (training), plus the tri-service Andaman and Nicobar Command at Port Blair. That Nipun is built at Visakhapatnam and commissioned at Mumbai simply reflects where the yard is and where the ship will be based.
The strategic argument
There is a diplomatic dimension that a strong answer should reach. Submarine rescue is a capability very few navies possess, and one that is meaningless if held selfishly — a submarine emergency is a race against a fixed air supply, and the nearest capable ship is the one that matters, regardless of flag. Navies with rescue assets therefore commit to assisting others, and India's stated aspiration is to be a preferred submarine rescue partner in the Indian Ocean Region.
That fits an established pattern in Indian maritime policy: capability offered as a regional public good. It is the same logic as first responder assistance in humanitarian crises, and it belongs with the SAGAR framing — Security and Growth for All in the Region — that recurs across defence current affairs. For candidates, this is the sort of institutional and strategic scaffolding the NDA general knowledge paper draws on directly.
🔑 Revision block
The event. 25 August 2026 — Ministry of Defence announced that Nipun, the second Nistar-class Diving Support Vessel, will be commissioned on 31 August 2026 at Naval Dockyard, Mumbai. Delivered to the Navy on 30 July 2026.
Builder. Hindustan Shipyard Limited (HSL), Visakhapatnam — indigenously designed and constructed. HSL came under the Ministry of Defence in 2010.
The first of class. INS Nistar, commissioned July 2025 — India's first indigenously designed and built DSV. About 118 m, roughly 10,000 tonnes, saturation diving support to about 300 m, ROVs working deeper. Over 80% indigenous content, about 120 MSMEs in the supply chain.
Saturation diving — the concept. Decompression time, not depth, limits deep diving. Once tissues are saturated at a pressure, extra time adds no decompression penalty. Divers therefore live in a pressurised chamber, transfer to work by diving bell, and decompress once at the end. Converts minutes of useful work into weeks.
Submarine rescue. The DSV is a mothership for a Deep Submergence Rescue Vehicle (DSRV), which mates with a disabled submarine's escape hatch. The binding constraint is how fast the DSRV reaches the site, which is why the mothership matters as much as the submersible. India holds DSRV capability on both coasts.
Other roles. Underwater intervention, salvage, hull repair, moorings, and ROV support.
The names. Nistar = deliverance/rescue; Nipun = skilled/adept. The earlier INS Nistar was a Soviet-origin submarine rescue vessel from the early 1970s.
Shipyard map. MDL Mumbai — destroyers, Scorpene submarines · GRSE Kolkata — frigates, corvettes · GSL Goa — OPVs, Coast Guard ships · CSL Kochi — INS Vikrant · HSL Visakhapatnam — Nistar-class DSVs, fleet support ships.
Naval commands. Western — Mumbai · Eastern — Visakhapatnam · Southern — Kochi (training); tri-service Andaman and Nicobar Command — Port Blair.
The strategic point. Submarine rescue is held by few navies and is useless if hoarded — India aims to be a preferred submarine rescue partner in the Indian Ocean Region, consistent with SAGAR and the first-responder role.
🎯 Practice MCQs
Q1. Nipun is which type of vessel? (a) Diving Support Vessel (b) Guided-missile destroyer (c) Landing platform dock (d) Survey vessel → (a) — second of the Nistar-class.
Q2. Nipun has been built by: (a) Hindustan Shipyard Limited, Visakhapatnam (b) Mazagon Dock, Mumbai (c) Cochin Shipyard (d) Goa Shipyard → (a).
Q3. The first indigenously designed and constructed Diving Support Vessel of the Indian Navy was: (a) INS Nistar (b) INS Vikrant (c) INS Chennai (d) INS Nipun → (a) — commissioned in July 2025.
Q4. In saturation diving, divers live in a pressurised chamber because: (a) once tissues are saturated, extra time at depth adds no decompression penalty (b) it is warmer (c) oxygen is cheaper (d) it prevents seasickness → (a).
Q5. A DSRV is used to: (a) rescue the crew of a disabled submarine (b) launch cruise missiles (c) lay mines (d) survey the seabed for oil → (a) — mating with the submarine's escape hatch.
Q6. India's first indigenous aircraft carrier, INS Vikrant, was built at: (a) Cochin Shipyard Limited (b) Mazagon Dock (c) GRSE Kolkata (d) HSL Visakhapatnam → (a).
Q7. Hindustan Shipyard Limited was transferred to the Ministry of Defence in: (a) 2010 (b) 1971 (c) 2025 (d) 1999 → (a).
Q8. Scorpene-class submarines are built in India at: (a) Mazagon Dock Shipbuilders (b) Goa Shipyard (c) GRSE (d) HSL → (a).
Q9. Nipun will be commissioned at: (a) Naval Dockyard, Mumbai (b) Visakhapatnam (c) Kochi (d) Port Blair → (a) — though it was built at Visakhapatnam.
Q10. INS Nistar supports saturation diving to approximately: (a) 300 m (b) 100 m (c) 1,000 m (d) 6,000 m → (a) — ROVs operate deeper.
Q11. The Southern Naval Command, headquartered at Kochi, is primarily the: (a) training command (b) strike command (c) submarine command (d) tri-service command → (a).
Q12. India's stated maritime vision emphasising regional security and growth is: (a) SAGAR (b) Sagarmala (c) Samudrayaan (d) Sagar Sampada → (a) — Security and Growth for All in the Region.
📋 How this gets asked (PYQ pattern)
Naval-induction questions follow four familiar shapes. The ship-to-yard item — matching a vessel to the shipyard that built it, where MDL, GRSE, GSL, CSL and HSL are set against one another and INS Vikrant with Cochin Shipyard is the anchor fact. The class item — naming the lead ship of a class, with Nistar-class now joining Kolkata-class, Shivalik-class and Kamorta-class in the rotation. The command item — naval commands and their headquarters, plus the tri-service outlier at Port Blair. The capability item — what a specific platform does, where a DSV, a survey vessel and a fleet support ship are easy to confuse.
The fresh 2026 hook is Nipun as the second Nistar-class DSV and its 31 August 2026 commissioning. A statement-type item pairing the class with the builder is the most likely single question, and the trap will be assigning it to Mazagon Dock. As always, we describe the recurring pattern, not any exact past question.
Preparing for the NDA? Every ship induction is really four facts — class, yard, role, base — and candidates who file them that way answer in seconds. Build the framework with our NDA general knowledge notes, follow the daily NDA current affairs, and train with our ex-officer faculty in the upcoming Cavalier courses in Delhi.
✍️ Written by Col Vijyanat Thakur — Defence & strategic affairs faculty at The Cavalier. Reviewed by the Cavalier Faculty Desk. The Cavalier, founded by ex-Army officers, has trained NDA/CDS/SSB aspirants since 2001 (Facebook · YouTube).
Source: PIB / Ministry of Defence, 25 August 2026. Nistar-class specifications cross-verified with independent defence reporting.