Force eight winds on Thursday thwarted a planned attempt to bring the Norman Atlantic back to Italy for checking whether there are any more bodies on board the burnt-out ferry.
Bari prosecutor Giuseppe Volpe has ordered the Italian-owned vessel be towed to the southern port of Brindisi as soon as possible so that it can be inspected for corpses and for clues as to what caused the huge fire that erupted on board on Sunday.
The fire led to the deaths of at least 13 people, possibly many more.
But with the powerful winds and choppy seas forecast to continue to Friday, it was unclear when the tugboats currently stabilising the giant ship would be able to make the 60-mile crossing from waters just off Albania.
Volpe has said he expects to find more bodies on board, notably because he suspects there were more stowaways on board than the three — two Afghans and a Syrian — who were rescued by the Italian coastguard on Monday.
There is also a possibility that passengers who were sleeping in their cabins when the fire erupted may never have made it out of them.
Several survivors have said the fire was blazing powerfully before any alarm was sounded and some said it was only the smell of smoke or other passengers banging on their doors that woke them up.
– Numbers unclear –
Anek Lines, the Greek company which chartered the ferry, has slighly revised the total number of passengers and crew it thinks were on board three times since Sunday, finally settling on a figure of 474.
Volpe says the total was 499 with the discrepancy accounted for by the three stowaway survivors and 18 other passengers who were squeezed on to the overbooked vessel at the last minute.
That has generated fears that the scale of the disaster could be substantially greater than first thought with the Italian authorities initially saying only 427 people had been taken off the boat alive.
That figure was revised upwards to 477 on Thursday following cross checking with all the various military and merchant ships which were involved in ferrying passengers winched off the Norman Atlantic to ports in Greece and Italy over the course of four days.
The list has been sent to Greece for cross-checking with the initial passenger list, Italian media reported quoting officials who could not be reached for confirmation.
The 13 confirmed dead so far included 11 passengers and two Albanian seamen killed in an accident during the rescue operation.
The bodies of nine of the passengers have been recovered while two other victims were identified as dead in the water but floated out of reach of rescuers.
The Italian navy scaled back its search for bodies with seven helicopters returning to base late on Wednesday, although a navy ship and one helicopter remain in the area.
– Runaway ferry details –
Italy's Red Cross meanwhile provided further alarming details of how a freighter ship with more than 700 mostly Syrian migrants was set on an autopilot collision course with the country's rocky coastline and then abandoned by the people smugglers in charge of it.
The boat was five miles and less than an hour from the rocks when six Italian sailors were dropped onto it by helicopter and applied the brakes.
The Red Cross said there had been 60 children and two pregnant women on the ship, one of whom gave birth on board.
Many of the migrants were suffering from hypothermia and injuries including broken limbs but fears of several deaths proved to be unfounded, according to the Red Cross.