New Delhi/ Panaji, March 23: Coast Guard patrol vessels and aircraft were battling today to stave off an oil slick from lashing a marine reserve off India?s beach capital Goa after a Singaporean cargo ship?s fuel tank leaked when a barge collided against it past midnight.

The merchant vessel Maritime Wisdom was at anchorage four nautical miles off Goa?s Fort Aguada when a barge, the Prapti, trying to get alongside it in bad weather and swollen sea for transhipment of iron ore hit the fuel tank in the cargo vessel?s aft.

This evening, the slick was about a mile long and 20-100 metres wide. Coast Guard operations headquarters in New Delhi was plotting its course and estimated that it was likely to pass one nautical mile (about 2,020 yards) west of Grande Island, a divers? destination, near the Bogmalo and Majorda beaches of south Goa.

?Luckily, winds and currents are taking the slick in a southerly direction. With the dispersants that are being sprayed by our aircraft and ships, we expect the slick to disintegrate. If the slick moves eastwards (towards the coastline) we will use ocean booms to contain it and pump in the oil,? Coast Guard deputy inspector general Abu Thalha said.

Thalha heads the Coast Guard?s fisheries and environment directorate.

Grande is the largest of a group called the St George?s Islands about two miles west of Bogmalo in south Goa. It is frequented by tourists and marine archaeologists on diving expeditions to explore the St George?s coral reef, glimpse schools of colourful fish and for wrecks of Portuguese and Spanish galleons.

Thalha said furnace fuel oil gushed out of the Maritime Wisdom?s tank through a hole, measuring 15 cm x 7.5 cm, after the Prapti hit it despite being warned around 1 am. Most of the fuel was pumped into an adjacent tank and by this morning the leak was plugged. A Coast Guard Chetak helicopter took off from the base near Mormugao port at first light to survey the slick and assess its damage potential.

By 11.30 in the morning, the slick had floated 5.4 nautical miles south from where the Maritime Wisdom was anchored. At 1.15 in the afternoon, it was reported to be 2.4 nautical miles northwest of Grande Island and was headed southeast and closer to Grande. It was expected to be one nautical mile west of the western tip of Grande in the evening.

A Coast Guard interceptor craft, a C140, sailed close to the slick in the afternoon. Mormugao Port Trust vessels equipped with oil dispersants were also despatched.

In the late afternoon, two Coast Guard Dornier aircraft from Daman sprayed oil spill dispersants and reported that the slick was ?breaking up into patches?.

But the unpredictability of wind and weather conditions led the Coast Guard to call in two more pollution control vessels from the base in Mumbai. The offshore patrol vessel, the Vigraha, and the advanced offshore patrol vessel, the Sagar, equipped with pollution response equipment are expected to reach the site late tonight.

The Coast Guard, which is the nodal agency for the National Oil Spill Disaster Contingency Plan, has sent reports to the defence and environment ministries.

Maritime nations across the world were alerted to oil spill disasters since the slick from a tanker, the Exxon Valdez, threatened the Alaska coastline in March 1989. Oil spill disaster management in India is still relatively new. Today?s spill was the 60th that the Coast Guard was tackling since 1982. The last was a minor spill, also in Goa, in October 2004 when about 600 litres of kerosene spilled from a ship in the harbour.

The biggest oil spill in Indian waters was off the Andaman and Nicobar Islands in 1993 when about 40,000 tonnes were emptied from the M.V. Maersk Navigator. Then, too, luck played a role and the slick floated by the islands.