Mumbai, Feb. 22: India's accident-prone navy suffered another mishap last week but, in keeping with a new "philosophy" relating to "minor incidents", chose to underplay it by not ordering a board of inquiry.

Jinxed submarine INS Sindhughosh, which had run aground at Mumbai harbour last January while returning to the western naval dockyard, endured its latest misfortune off the Goa coast.

The freak accident happened sometime during Thursday night or early Friday morning while the submarine was participating in the high-profile naval exercise Tropex 2015.

"Trying to surface during the course of the exercise, the boat hit a fishing vessel which broke its periscope," a source at the Western Naval Command in Mumbai said.

"Defence minister Manohar Parrikar was to arrive the day after and spend a day aboard the aircraft carrier INS Vikramaditya. So, as part of a new, unstated policy at naval headquarters, it was decided the navy would inform the defence ministry about the incident but not set up a board of inquiry so as not to focus on small lapses."

A board of inquiry is called after a naval mishap or incident. It determines the facts and the cause and takes corrective and disciplinary action, if necessary.

"Setting up a board of inquiry immediately brings the incident into public focus because of the media attention nowadays. The navy's new philosophy is to avoid negative publicity over minor incidents," a senior navy officer said.

"The exercise was being conducted in pitch dark conditions as required by the exercise prerequisites. The incident happened during the night between Thursday and Friday," the statement said.

It said there were "no major damages to the submarine". INS Sindhughosh has returned to the Mumbai harbour and the repairs are set to start.

This is the fourth accident involving the Russian-made Kilo-class submarine that specialises in anti-submarine and anti-surface-warfare capabilities.

During a fleet-level exercise in January 2008, it had collided with a foreign merchant vessel while trying to surface off the Diu coast. In August 2013, it suffered fire damage after the INS Sindhurakshak, another submarine docked next to it, imploded.

In January 2014, it ran aground in low tide while returning to the naval dockyard in Mumbai. The Sindhughosh is the lead ship of this class of diesel-electric subs in India's navy.