MV Bingo's 18-member crew, comprising mostly Chinese nationals, were believed to have left the ship on a lifeboat and are yet to be located. Rescue aircraft have been pressed into service to trace the sailors.
"In all likelihood the ship must have sunk otherwise it would have been located by now. Search operations are still on and we are looking for the crew which it seems must have been picked up by any other vessel," a Coast Guard spokesperson said.
The ship carrying iron ore, left the Haldia Dock Complex (HDC) Saturday and was last located 25 nautical miles south-southwest of Sagar Island, about 100 km from Kolkata.
Cyclonic storm Phailin Saturday night slammed India's east coast near Gopalpur in Odisha, triggering heavy rains and strong winds with speed reaching up to 200 km an hour.
More than 500,000 people were shifted to safety in coastal Odisha and Andhra Pradesh.