This is coolbert:
Down the hatch!! How many times have we read about this before. Many of them. From various sources and the tip from Freeper.
"Someone Left a Hatch Open and Crippled India’s $2.9 Billion Submarine"
"India’s first ballistic missile submarine was out of commission for ten months after someone neglected to properly close a hatch."
"This incident was first reported by The Hindu. According to an Indian Navy source, a hatch was left open on the rear left side of the ship, allowing seawater to run into the propulsion area while the Arihant was in Harbor."
More danger apparently to a submarine when the vessel docked in harbor, idle, not at sea!
See previous blog entry as is relevant and germane with additional embedded links: