Two more tugboats were on their way on Sunday to join efforts to refloat a massive container ship wedged across the Suez Canal since last week, blocking traffic in the vital trade route and disrupting global trade.
The Dutch-flagged Alp Guard and the Italian-flagged Carlo Magno are believed to have arrived near the city of Suez at the southern mouth of the Suez Canal.
The two tugs have a combined pulling power of almost 500 tonnes.
They will join a dozen other tug boats that have been involved in efforts, unsuccessful so far, to refloat the ship.
Sunday was expected to witness two attempts coinciding with tides to free the Panama-flagged, 400-metre-long Ever Given, the first about midday and a second time in the evening.
Repeated failures to refloat the 200,000-tonne vessel are likely to force the Suez Canal Authority, which manages the waterway, to resort to offloading the vessel, which is carrying 18,300 containers.
That delicate operation could take days to complete and will probably involve container ships equipped with suitable cranes.
“It is our last resort scenario,” the Suez Canal Authority's chief, Adm Osama Rabie, told a news conference on Saturday.
For now, hopes are pinned on the power of the two additional tugs as dredging operations continue, sucking sand from underneath the vessel.
In a statement issued on Sunday, he said the latest attempt to refloat the vessel on Saturday involved 12 tugboats, two pulling the front of the ship and 10 more pushing its rear southward.
Two new tugboats being built in a shipyard at Port Said, the coastal city on the northern tip of the canal, were due to join the effort. He did not give a precise date.
Also on Sunday, he said the main dredger has so far removed 27,000 cubic metres of sand, reaching a depth of 18 metres.
Workers have removed thousands of tonnes of ballast from the Ever Given and brought in more tugboats in an expanding effort to refloat the ship.
Adm Rabieh said 9,000 tonnes of ballast water were pumped out to lighten the vessel.
Fourteen tugboats, as well as dredgers, are now part of the operation and they could look to unload some weight off the vessel if the current efforts are not successful, Adm Rabieh said.
“We have to deal with difficult soil and strong tides in addition to the size of the boat, its height and the large number of containers it is carrying,” he said.
He declined to give a timetable for the refloating of the vessel.
“It is very difficult to give a precise time for resolving the problem,” he said.
In the meantime, ships continue to arrive at either end of the canal, waiting to pass.
Adm Rabieh said 321 ships were stuck in the canal and its lakes. He announced the closure of the waterway on Thursday.
The Ever Given ran aground on Tuesday in a narrow stretch of the canal just north of the city of Suez after it was blown off course by strong winds during a sandstorm. Two pilots from the canal authority were on board the Ever Given when it became stuck.
Initially, authorities and the operator said wind and a sandstorm pushed the ship off course and into the side of the canal.
However, Adm Rabieh on Saturday said that bad weather was not the only cause of the Ever Given running aground and that technical or human error could have contributed.
“When it comes to big accidents like this one, there is always more than one cause. The investigation could reveal a human error or a technical fault,” said Adm Rabieh. No formal investigation into how the accident occurred will begin before the ship is refloated and traffic returns to normal, he said.
Besides the Dutch-based Smit International, Japan’s Nippon Salvage is also participating in the refloating effort.
Canal authorities say nearly 20,000 cubic metres of sand must be dredged from around the ship for it to move.
At a press conference in Japan on Friday, Yukito Higaki, president of Shoei Kisen, which owns the Ever Given, said there were no signs of damage to its engines and instruments.
"The ship is not taking water. There is no problem with its rudders and propellers. Once it refloats, it should be able to operate," Mr Higaki said, according to Asahi Shimbun.
The blockage of the Suez, which links the Mediterranean and the Red Sea, has left hundreds of ships on both ends of the trade route waiting to pass through.
Some of those that were not already in the canal when the Ever Given ran aground are opting to take the much longer route around South Africa's Cape of Good Hope to Europe or Asia.
However, Adm Rabieh said the current crisis would not take away the edge of the Suez Canal as the shortest and more economic route between Asia and Europe.
“The route around the Cape of Good is not safe,” he said, alluding to piracy off the eastern coast of Africa.
The effect of delays has doubled shipping costs for oil-related products since the ship ran aground, experts said.
The blockage could cost global trade between $6 billion and $10bn a week, a study by German insurer Allianz showed on Friday.
"The problem is that the Suez Canal blockage is the straw that breaks global trade's back," the study's authors wrote.