INS Arihant Class Submarine

📜 Background & Purpose

Strategic Role: SSBNs like Arihant form the sea-based leg of India’s nuclear triad — enabling a credible second-strike capability by keeping nuclear weapons survivable at sea even after a first strike.
Army Recognition

Project Origin: Conceived in the 1990s under the highly classified Advanced Technology Vessel program, combining efforts of the Indian Navy, DRDO, Department of Atomic Energy (DAE) and other Indian defence organisations, with technical assistance from Russia early on.

Indigenisation: These are the first SSBNs designed and built in India — a significant technological milestone.

🛠️ Technical Design & Propulsion

Hull & Size:

Length: ~111–130 m (varies across boats)

Beam: ~11 m

Displacement: ~6,000 – 7,000 tonnes submerged.

Nuclear Reactor:

Each boat is powered by a compact pressurized light-water reactor (≈83 MW) with nuclear fuel, providing virtually unlimited range limited only by crew endurance and supplies.

Speed:

~12–15 knots surfaced

~24 knots submerged.
Wikipedia

Stealth & Structure:

Double-hull construction with specialized sound-absorbing tiles to reduce acoustic signature.

Designed based on experience with Russian Akula-class designs but significantly modified.
Naval Technology

Crew:

Around 90–95 officers and sailors.