Suez Canal salvage teams were alternating between dredging and tugging yesterday to dislodge a massive container ship blocking the busy waterway, while two sources said efforts had been complicated by rock under the ship's bow. 

Dredgers working to dislodge the stranded vessel have so far shifted 27,000 cubic metres of sand, to a depth of 18 metres, and efforts would continue around the clock according to wind conditions and tides, the Suez Canal Authority (SCA) said in a statement.

Egypt's President Abdel Fattah al-Sisi has ordered preparations for the possible removal of some of the ship's cargo to help refloat it, SCA Chairman Osama Rabie told Egypt's Extra News.

The 400-metre (430-yard) long Ever Given became jammed diagonally across a southern section of the canal in high winds more than five days ago, halting shipping traffic in one of the world's busiest waterways.

As of Saturday, 321 boats were waiting to transit the canal, including dozens of container ships, bulk carriers and liquefied natural gas (LNG) or liquefied petroleum gas (LPG) vessels.

About 15% of world shipping traffic transits the Suez Canal.

Shipping rates for oil product tankers nearly doubled after the ship became stranded, and the blockage has disrupted global supply chains, threatening costly delays for companies already dealing with COVID-19 restrictions.

If the blockage drags on, shippers may decide to reroute their cargoes around the Cape of Good Hope, adding about two weeks to journeys and extra fuel costs.