Indian Submarine Bumps Merchant Ship

Vigilis has a lot of information on the news that INS Sindhughosh (S 55), an Indian Kilo-class submarine, had a minor collision with MV Leeds Castle. According to this story in the Indian press:
At the time of the collision, the submarine was plying in shallow waters of the Arabian sea at periscope depth when the large merchant ship grazed over it damaging the submerged vessel's aerial radar and fin, sources here said.
Luckily, it appears no one was hurt, and the sub returned to Mumbai under her own power. Some in India are already blaming the potential failure of boat's indigenously-produced sonar system for failing to detect the merchant; as us U.S. submariners know, however, sometimes not even the world's best sonar can keep a boat from coming out on the wrong side of the "big ocean / little ship" probabilities.