An exercise between two navies has two halves, and most people only picture the second one.
The 13th edition of SLINEX, the Sri Lanka-India bilateral maritime exercise, is being conducted at Visakhapatnam from 17 to 21 September 2026. It opened with the Harbour Phase, to be followed by the Sea Phase. From the Indian Navy: INS Kavaratti, an indigenous anti-submarine warfare corvette, and INS Jyoti, a fleet tanker. From the Sri Lanka Navy: SLNS Sindurala. The harbour phase is conducted under the aegis of Eastern Naval Command.
SLINEX was conceptualised in 2005.
The two phases, and why the first one is not filler
The Harbour Phase is the part that gets skimmed in reporting. At Visakhapatnam it opened with a ceremony and a reception aboard INS Kavaratti for the visiting crew of SLNS Sindurala, and includes professional interactions, cross-deck visits, sharing of best practices, and Yoga, sports and cultural activities.
It is tempting to read that as hospitality. It is preparation, and the reason is worth understanding.
Two warships that are about to manoeuvre in close company at sea need agreement on a large number of small things beforehand: which radio frequencies, which callsigns, what a given signal means, how a turn will be ordered and acknowledged, what happens if communication fails, how close is close enough. Settling that in harbour, on paper and face to face, is what makes the sea phase safe. Settling it at sea, at speed, is how collisions happen.
Cross-deck visits do something the paperwork cannot. An officer who has physically stood on the other ship's bridge, seen its layout and met the people who will be answering the radio has a mental model of what is happening on the other side of a transmission. That is not sentiment; it is situational awareness bought cheaply in harbour.
The Sea Phase then focuses on operational synergy and interoperability through coordinated activities at sea.
Interoperability is the recurring objective across all of India's naval engagements, and its definition is worth having exactly: the ability of two forces to operate together effectively without prior integration. A contingency — a humanitarian evacuation, a search and rescue, an anti-piracy response — gives no time to build it. It has to exist already.
The ships, and why this pairing
INS Kavaratti is the fourth and final Kamorta-class anti-submarine warfare corvette, built under Project 28 by Garden Reach Shipbuilders and Engineers (GRSE), Kolkata, and commissioned on 22 October 2020 at Naval Dockyard, Visakhapatnam.
Her specifications are worth holding because the class is regularly examined: about 109 metres in length, 14 metres in beam, 3,300 tonnes displacement, with up to 90 per cent indigenous content. Her superstructure uses carbon composites, which lowers top weight, reduces maintenance and improves stealth — a composite superstructure returns less radar energy than a steel one.
The primary role of the class is anti-submarine warfare, with secondary anti-surface and anti-air capability.
INS Jyoti is a fleet tanker — a replenishment ship. This is the less glamorous and arguably more significant of the two Indian participants, because a fleet tanker is what converts a navy that can defend its coast into a navy that can operate away from it.
A warship's endurance is limited by fuel, fresh water, food and ammunition. Without replenishment at sea, a task group must periodically return to port or find a friendly harbour, and its radius of action is effectively half the distance it can travel on one tank. A tanker steaming with the group removes that constraint. Navies distinguish themselves on precisely this capability: sea legs are a logistics achievement, not a hull design one.
Which is why a tanker's presence at SLINEX is not incidental. Replenishment at sea between ships of different navies is among the most demanding things two fleets can practise together — two ships parallel, close aboard, connected by lines and hoses, holding course and speed for an extended period. A navy that can take fuel from another navy's tanker has achieved something well beyond a courtesy visit.
The strategic frame, briefly
SLINEX is described as aligned with India's MAHASAGAR vision, and reinforcing a secure, stable and inclusive maritime environment. We have set out that framework and its evolution from SAGAR in our fuller treatment of Vision MAHASAGAR and the Indian Ocean Region, so it needs no repetition here.
What is specific to Sri Lanka is geography. The island sits astride the sea lanes running between the Arabian Sea and the Bay of Bengal, a short distance from the southern tip of the Indian peninsula, separated by the Gulf of Mannar and the Palk Strait. Any maritime activity around Sri Lanka is, by position, activity in India's immediate approaches. That proximity is the reason a bilateral exercise with a navy far smaller than India's has been sustained for thirteen editions across two decades.
The thirteen editions matter more than the thirteenth. A single exercise builds little. A sequence running from 2005 produces something specific: officers on both sides who have worked together at successive ranks, procedures that have been refined rather than invented, and an institutional relationship that survives changes of government. Continuity is the product here, and it is the reason to note "13th edition" as the most informative fact in the announcement.
A note on exercise vocabulary
Candidates routinely lose marks by conflating categories of naval engagement. Three distinct things:
A named bilateral exercise — planned, recurring, usually annual, with a fixed name and numbered editions. SLINEX with Sri Lanka, Varuna with France, Konkan with the United Kingdom, SIMBEX with Singapore, Indra with Russia, AUSINDEX with Australia.
A named multilateral exercise — Malabar with the United States, Japan and Australia; MILAN, the multinational gathering hosted by India; AIKEYME with African navies.
A PASSEX — a Passage Exercise, arranged at short notice between ships that happen to be in proximity, lasting hours, with no numbered edition.
A question that names an exercise is often testing which of these three it is. Our NDA study material on general knowledge carries the full exercise-and-partner table.
🔑 Revision block
The exercise. SLINEX-26 — the 13th edition of the Sri Lanka-India bilateral maritime exercise, at Visakhapatnam, 17 to 21 September 2026. Conceptualised in 2005. Harbour Phase under Eastern Naval Command.
Participants. Indian Navy — INS Kavaratti (indigenous ASW corvette) and INS Jyoti (fleet tanker). Sri Lanka Navy — SLNS Sindurala.
Two phases. Harbour Phase — opening ceremony and reception, professional interactions, cross-deck visits, sharing of best practices, Yoga, sports and cultural activities. It settles frequencies, callsigns, signals and procedures before the ships are at sea. Sea Phase — operational synergy and interoperability through coordinated activity at sea.
Interoperability. The ability of two forces to operate together effectively without prior integration — it must exist before a contingency, not be built during one.
INS Kavaratti. Fourth and final Kamorta-class ASW corvette, Project 28, built by GRSE, Kolkata, commissioned 22 October 2020 at Visakhapatnam. About 109 m long, 14 m beam, 3,300 tonnes, up to 90 per cent indigenous content, carbon-composite superstructure for lower top weight, reduced maintenance and better stealth. Primary role ASW, with anti-surface and anti-air capability.
INS Jyoti — fleet tanker. Replenishment at sea removes the fuel, water, food and ammunition constraint on endurance. Without it, a task group's radius is roughly half what it can travel on one tank. Sea legs are a logistics achievement. Cross-navy replenishment is among the most demanding things two fleets can practise.
Geography. Sri Lanka sits astride the lanes between the Arabian Sea and the Bay of Bengal, separated from India by the Gulf of Mannar and the Palk Strait — activity around Sri Lanka is activity in India's immediate approaches.
Why 13 editions matter. Continuity produces officers who have worked together at successive ranks, refined procedures, and a relationship that survives changes of government.
Three categories of exercise. Named bilateral — SLINEX (Sri Lanka), Varuna (France), Konkan (UK), SIMBEX (Singapore), Indra (Russia), AUSINDEX (Australia). Named multilateral — Malabar (US, Japan, Australia), MILAN (multinational, hosted by India), AIKEYME (African navies). PASSEX — short-notice, unnumbered, between ships in proximity.
🎯 Practice MCQs
Q1. SLINEX is the bilateral maritime exercise between India and: (a) Singapore (b) Sri Lanka (c) Seychelles (d) South Africa
→ (b) — SIMBEX is with Singapore.
Q2. INS Kavaratti belongs to which class of ships? (a) Kamorta class (b) Kolkata class (c) Talwar class (d) Shivalik class
→ (a) — the fourth and final ship of the class, under Project 28.
Q3. INS Kavaratti was built by: (a) Mazagon Dock Shipbuilders (b) Cochin Shipyard Limited (c) Garden Reach Shipbuilders and Engineers (d) Hindustan Shipyard Limited
→ (c)
Q4. The primary role of the Kamorta-class corvettes is: (a) Air defence (b) Anti-submarine warfare (c) Amphibious assault (d) Mine countermeasures
→ (b)
Q5. The principal advantage of a carbon-composite superstructure on a warship is: (a) Increased crew capacity (b) Lower top weight, reduced maintenance and improved stealth (c) Higher maximum speed (d) Greater fuel capacity
→ (b)
Q6. A fleet tanker's essential contribution to naval operations is: (a) Anti-aircraft protection of the task group (b) Replenishment at sea, extending the group's radius of action (c) Submarine detection (d) Command and control of the formation
→ (b)
Q7. SLINEX was conceptualised in: (a) 1995 (b) 2005 (c) 2012 (d) 2018
→ (b)
Q8. Sri Lanka is separated from the Indian mainland by the: (a) Ten Degree Channel and Gulf of Kutch (b) Palk Strait and Gulf of Mannar (c) Nine Degree Channel and Gulf of Khambhat (d) Strait of Malacca
→ (b)
Q9. Which of the following is a multilateral rather than a bilateral naval exercise? (a) SLINEX (b) Varuna (c) Malabar (d) SIMBEX
→ (c) — with the United States, Japan and Australia.
Q10. Consider the following statements about the harbour phase of a bilateral naval exercise: 1. It is primarily ceremonial and contributes little to the exercise's operational value. 2. It is used to agree frequencies, signals and procedures before ships operate in close company at sea. Which is/are correct? (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2
→ (b) — settling procedures ashore is what makes the sea phase safe.
📋 How this gets asked (PYQ pattern)
Naval exercises are among the most reliably examined items in the NDA General Knowledge paper, and the question forms are stable enough to prepare exhaustively.
The exercise-and-partner question is the most common, and it is best answered from a memorised table rather than by reasoning. The names that recur are SLINEX, SIMBEX, Varuna, Konkan, Indra, AUSINDEX, Malabar, MILAN and AIKEYME. Note that several exercise names are shared across services — Indra has naval, army and air components with Russia, and Garuda is the air exercise with France while Varuna is the naval one. Questions exploit exactly that overlap.
The ship-class question asks which class a named ship belongs to, its builder, or its primary role. Project numbers are worth attaching where they exist: Project 28 for the Kamorta-class ASW corvettes, Project 15B for the Visakhapatnam-class destroyers, Project 17A for the Nilgiri-class frigates.
The concept question covers interoperability, replenishment at sea, sea legs and the phase structure of an exercise. This is the category that transfers to the SSB interview, where a candidate who can explain why a tanker matters is making a different impression from one who can list ship names.
The geography question attaches the exercise to its water. The Palk Strait and Gulf of Mannar for Sri Lanka, the Ten Degree Channel for the Andaman and Nicobar groups, the Nine Degree Channel within Lakshadweep. These four recur constantly and are confused just as often.
Preparing for the NDA? Naval exercises repay a single memorised table — name, partner, bilateral or multilateral — and then one concept per story. Build the base with our NDA study material, follow the daily NDA current affairs, and prepare with our faculty in the upcoming Cavalier courses in Delhi.
✍️ Written by Maj Sunil Chopra — Co-founder and defence studies faculty at The Cavalier. Reviewed by the Cavalier Faculty Desk.