An oil removal ship is seen next to the Costa Concordia cruise ship as it ran aground off the west coast of Italy at Giglio island, January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.

A scuba diver inspects a side of the Costa Concordia cruise ship, seen underwater after it ran aground off the west coast of Italy, at Giglio island in this photo released on January 16, 2012.

Passengers arrive at Porto Santo Stefano after a cruise ship ran aground off the west coast of Italy at Giglio island January 14, 2012. At least three people were killed and rescuers were looking for other victims on Saturday after Costa Concordia, a large Italian cruise ship, carrying more than 4,000 people ran aground overnight, took on water and tipped over.

Rescue workers with divers check on a side of the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island January 17, 2012

A view shows the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island January 15, 2012. Rescuers were painstakingly checking thousands of cabins on the Italian liner for 15 people still unaccounted for after the huge vessel foundered and keeled over, killing at least five people and injuring 70.

The Costa Concordia cruise ship is seen after it ran aground off the west coast of Italy, at Giglio island January 16, 2012. Rescue workers searching the half-submerged hulk of an Italian cruise ship for missing passengers and crew recovered a sixth body on Monday, more than 48 hours after the vessel capsized off Italy's west coast.

Rescue workers inspect the capsized Costa Concordia cruise ship that ran aground off the west coast of Italy at Giglio island January 16, 2012. Rescue workers searching the half-submerged hulk of an Italian cruise ship for missing passengers and crew recovered a sixth body on Monday, more than 48 hours after the vessel capsized off Italy's west coast.

A breach is seen underwater on the side of the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.

An Italian Coast guard diver inspects the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.

The Costa Concordia cruise ship is seen off the west coast of Italy, at Giglio Island January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.

The Costa Concordia cruise ship that ran aground off the west coast of Italy at Giglio island is seen, January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.

The capsized Costa Concordia cruise ship is seen from a rescue vessel near Giglio, Italy, January 13, 2012 in this still image taken from an amateur video shot by a German passenger and obtained January 14, 2012. Rescuers were painstakingly checking thousands of cabins on the Italian liner for 15 people still unaccounted for after the huge vessel foundered and keeled over, killing at least five people and injuring 70.

A side of the Costa Concordia cruise ship is seen underwater after it ran aground off the west coast of Italy, at Giglio island in this photo released on January 16, 2012. Rescue squads used controlled explosions on Tuesday to enter a sticken Italian crusie liner in the increasingly despairing hunt for survivors as authorities almost doubled their estimate of the number missing to 29 people.

A side of the Costa Concordia cruise ship is seen underwater after it ran aground off the west coast of Italy, at Giglio island in this photo released on January 16, 2012. Rescue squads used controlled explosions on Tuesday to enter a sticken Italian crusie liner in the increasingly despairing hunt for survivors as authorities almost doubled their estimate of the number missing to 29 people.

The Costa Concordia cruise ship is seen after it ran aground off the west coast of Italy, at Giglio island (Reuters)

A breach is seen underwater on the side of the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island in this photo released on January 16, 2012. Rescue squads used controlled explosions on Tuesday to enter a sticken Italian crusie liner in the increasingly despairing hunt for survivors as authorities almost doubled their estimate of the number missing to 29 people.

A side of the Costa Concordia cruise ship is seen underwater after it ran aground off the west coast of Italy, at Giglio island, in this photo released on January 16, 2012. Rescue squads used controlled explosions on Tuesday to enter a sticken Italian crusie liner in the increasingly despairing hunt for survivors, as authorities almost doubled their estimate of the number missing to 29 people.

Rescue workers inspect the side of the Costa Concordia cruise ship that ran aground off the west coast of Italy, at Giglio island, January 16, 2012. Over-reliance on electronic navigation systems and a failure of judgement by the captain are seen as possible reasons for one of the worst cruise liner disasters of all time, maritime specialists say.