A hatch left open on the INS Arihant lead to saltwater flooding the propulsion area, rendering the $2.9 billion submarine inoperative.

The incident was first reported by The Hindu. According to an Indian Navy source, a hatch was left open allowing seawater to rush in. The Arihant issue rose soon after INS Chakra, the Nerpa class nuclear submarine leased from Russia, was reported to have suffered damage to its sonar domes while entering the Visakhapatnam harbour in early October.

INS Arihant is to be the first of the expected five in the class of submarines designed and constructed as a part of the Indian Navy’s secretive Advanced Technology Vessel project. The Arihant class submarines are reported to be based on the Akula class submarine.

India has an ambitious plan to build a SSBN fleet, comprising five Arihant class vessels.

INS Arihant was introduced to the public in 2009 at a symbolic launch ceremony. The launch coincided with the 10th anniversary of the conclusion of the Kargil War and consisted of floating the vessel by flooding the dry dock. Defence Professionals Daily claimed Arihant was launched without key systems including its nuclear reactor, surveillance equipment, and ordnance.

Prime Minister Singh billed the submarine as an outcome of a public-private partnership. He also thanked Russia in his address, stating, “I would also like to express our appreciation to our Russian friends for their consistent and invaluable cooperation, which symbolises the close strategic partnership that we enjoy with Russia.”