Chennai, Nov 1 (IANS): The 15 crew members aboard oil tanker Pratibha Cauvery that ran aground here as cyclone Nilam hit Tamil Nadu coast Wednesday afternoon, were rescued early Thursday by Indian Coast Guard, an official said.

"Fifteen members on the ship were rescued today (Thursday) morning," a Coast Guard official told IANS here.

However, the whereabouts of six crew members of the Japanese-built ship were not known, said an official of the Mumbai-based Pratibha Shipping.

Anchored in Bay of Bengal near the Chennai Port, Pratibha Cauvery with 37 crew members started drifting towards the shore due to strong winds Wednesday. Cyclone Nilam was set to cross the coast between Mamallapuram and Kalpakkam Wednesday evening.

The ship ran aground Wednesday afternoon at the Elliots Beach or Besant Nagar beach, following which 22 members of the tanker clambered into a life boat, officials of Indian Coast Guard and the Chennai Port Trust said.

Hit by rogue waves, the boat capsized and six people went missing. Local fishermen in their country boats rescued 16 of the crew members who were holding on to the boat and were later admitted to hospital.

"Sixteen people were brought here, of whom one was brought dead. Three people are in the intensive care unit (ICU)," said S. Narasimhan, senior executive-patient care at the Fortis Malar Hospital.