While the identity of the victim was yet to be ascertained, the condition of two were said to be serious, sources in Chennai Port Trust said.
The crew member drowned after a life boat carrying him and 21 colleagues capsized in choppy waters off Besant Nagar locality in south Chennai in high velocity winds just hours before the cyclone hit the coast.
Fifteen sailors were rescued on Thursday and a search was on for six other missing crew who were on board an oil tanker that drifted and ran aground off the city coast in high velocity winds before the landfall of cyclone 'Nilam'.
"Around 6.30 am, 15 people who were stranded on board the vessel were safely rescued by the Coast Guard", Chennai Port Trust officials said.
Search involving the Navy and Coast Guard is on for the missing six persons, the officials said.
The vessel 'Pratibha Cauvery' with 37 crew on board ran aground near Elliott's Beach in South Chennai, about 200 metres away from the shore.
One crew member drowned after a life boat carrying him and his 21 colleagues capsized in choppy waters while 15 others were rescued with the help of several agencies including Navy and local fishermen yesterday.
The ship belonged to Mumbai-based Pratibha Shipping Company.
Two persons were killed in Tamil Nadu as Nilam crossed the coast between Tamil Nadu and Andhra Pradesh border yesterday without causing much damage.
The 26,000 tonne (DWT) capacity tanker had two tonnes of light diesel and furnace oil when the mishap occurred,they said.
Cyclone Nilam crosses TN coast, 2 dead
Cyclone Nilam on Wednesday swept across north Tamil Nadu coast near Mahabalipuram, about 55 km from here, leaving two persons dead, including a crew member of an oil tanker that ran aground off the city.
They had attempted to escape using the life boat after the ship with 37 crew ran aground having been drifted by high velocity winds. Two others are in a serious condition, Chennai Port Trust officials said.
Navy, Coast Guard and other agencies are searching for the remaining six. The other 15 remained onboard "Pratibha Cauvery", the officials said.
In Puducherry, a 46-year old man slipped into the rough sea and drowned when he, along with his friends, was walking on the pier to see the sea conditions during the cyclonic storm.
It was much relief to the authorities as the cyclone, forecast to be accompanied by wind speeds reaching 110 kmph, made the landfall with a maximum speed of only 65-75 kmph, saving the state of large-scale destruction.
About 4,000 people residing close to coast in Mahabalipuram, a famous tourist spot known for its temples and sculptures, were evacuated to safer places, officials said.
"Cyclonic storm NILAM moved north-northwestwards, crossed north Tamil Nadu coast near Mahabalipuram, south of Chennai between 4 pm and 5 pm today," a weather bulletin said.
The system, which brought heavy downpour in several parts of the state in the last two days, would move northwestwards and weaken into a deep depression during the next six hours.
It would continue to bring more rainfall over north coastal Tamil Nadu and Puducherry, even up to 25 cm or more, the bulletin said.
"Rainfall at most places with isolated heavy to very heavy falls would also occur over south coastal Andhra Pradesh, Rayalaseema and north interior Tamil Nadu during next 24 hours," it added.
Gale winds reaching up to 65-75 kmph gusting to 85 kmph would prevail along and off north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts in the next six hours and gradually decrease thereafter.
Sea condition will be very rough to high along and off north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts during the next six hours and fishermen have been warned against venturing into the sea till tomorrow.
Power supply was suspended in many parts of Chennai where more than 100 trees were uprooted by the storm, forcing people to remain largely indoors.
Educational institutions will remain closed in coastal districts of Tamil Nadu on Thursday, Chief Minister J Jayalalithaa said after reviewing the situation.
Southern Railways announced diversion and partial cancellation of trains, especially those passing through coastal districts.
Trains were also being operated at low speed to ensure safety, officials said.
A report from Karaikal in the union territory of Puducherry said life was affected in the town adjoining Tamil Nadu following heavy rains.
Officials said educational institutions in the district remained shut for third consecutive day.