Calcutta: Two vessels will start pumping 400-odd tonnes of fuel out of the submerged cargo ship MV SSL Kolkata that ran aground off the Sunderbans coast after catching fire on June 13.

Officials involved in the salvage operation said the vessels would leave Haldia early on Tuesday for the spot where the blaze-hit ship lies submerged. The vessels - Smit Borneo from Singapore and MCS Elly II from Bangladesh - had arrived at Haldia a few days back.

"The two could not start operations earlier because of bad weather," an official said. "Getting the oil out of the vessel is our priority. Once that is done, we'll try to salvage the vessel," he said.

The vessel contains about 400 tonnes of fuel, including generator oil.

The fuel tank of SSL Kolkata is under water. The salvage team will use a technology called "hot tapping" to suck the oil out of the submerged tank.

"There is no oil spill till now but we don't want to take chances," the official said. "It would take about 10 days to suck the oil out.... However, because of bad weather it may take even longer."

Smit Borneo has a 500-tonne crane that will be used to lift the containers that had fallen into the water from SSL Kolkata.

A crack on the upper deck of the affected ship has widened and the vessel has tilted about 35 degrees to its right. The crack had developed because of the fire and a series of explosions.

Later, water and sand entered the ship during high tide, damaging it further.

SSL Kolkata, loaded with 464 containers, had caught fire on the night of June 13 while it was on its way to Calcutta from Krishnapatnam port in Andhra Pradesh.