For more than half a century Egyptian navigation pilots kept the Suez Canal running smoothly, defying colonial powers’ predictions when Cairo nationalised the vital trade artery in 1956.

So when Ever Given, a colossal container ship, ran aground, it was a matter of national pride to get it moving. With hundreds of big ships piled up at the entrance of the waterway, a linchpin of global trade, Egypt’s canal authorities faced their toughest peacetime challenge, one in which both the country’s economic interests and its national prestige are bound up.

With the ship finally floated on Monday, tugboats sounded their horns. Abdel Fattah al-Sisi, the country’s president, said: “Egyptians proved today that they are up to their responsibilities and that the canal dug by the bodies of their forebears and defended by the lives of their fathers bears witness that Egyptians will determine their own destiny.”

For Egyptians the canal has not been just a foreign currency earner crucial to the economy, but also a symbol of sovereignty for which thousands sacrificed their lives in wars, and during the brutal digging process between 1859 and 1869.

The 1956 nationalisation sparked what Egyptians call the “tripartite aggression”, a war by Britain, France and Israel aimed at ousting President Gamal Abdel Nasser and replacing him with a compliant government. US pressure eventually forced the foreign powers to cease hostilities. The Egyptian leader’s popularity soared and the canal remains hugely important in Egypt today. The vital artery for world trade winds through the middle income country, the giant container ships towering over farmers tilling village fields.

“If you consider which of our national institutions functions well, definitely the Suez Canal will come on top,” said Mustapha Kamel Al-Sayyid, political science professor at Cairo University and a frequent regime critic.

But the crisis has led some to question the canal’s handling of big vessels such as the Ever Given, which represent a new generation of massive container ships.

Philip Edge, chief executive of UK freight forwarder Edge Worldwide Logistics, said the Suez Canal Authority’s emergency response and communications had overall been good considering the time it takes to get equipment such as tugboats to rescue sites. But he asked: “Why were vessels that big going through on their own? They should have a tug escort . . . It was travelling above the speed limit. There were two pilots from the canal authority on board, so what were they doing?”

Osama Rabie, head of the Suez Canal, has promised a full investigation into the grounding of the Ever Given to determine whether there was human or technical error in addition to strong winds. More than 18,000 ships had sailed through the canal last year without mishap including vessels bigger than the Ever Given, he said. “The ship is responsible for everything and so is the captain,” he said. “Suez Canal regulations say that the [Egyptian] pilots view is given in an advisory capacity to the captain.”

Over the years, Egypt has invested in the canal, particularly after it reopened following eight years during which it was shut down because of wars with Israel. “Since the reopening in 1975 Egypt has made great efforts to deepen and widen the canal,” said Al-Sayyid. In 2015, Egypt dug a 35km channel parallel to the canal to create a new lane and allow two-way traffic, an $8bn project funded by public bonds.

The canal remains a huge source of income for Egypt, providing more reliable receipts than tourism, the other big foreign exchange earner. Last year, it brought in $5.6bn, third only to tourism and remittances. Ranjith Raja, head of MENA oil and shipping research at Refinitiv, said that “with the canal accounting for a daily revenue of almost $16m, without transits for the past six days, the loss in revenue for the Suez Canal Authority and Egypt are in excess of $95m”.

Suez, the port city at the southern end of the canal, is known for its elegant colonial- style villas built by the French to house their canal officials. The Suez Canal Authority remains a big employer, but many also work in industry and farming. Locals voiced pride in the canal as well confidence that the Ever Given would be successfully floated.

In a mobile phone accessories shop, Mohamed Ahmed Ali, a salesman, remembers returning to Suez in 1973 after the war with Israel and seeing “destroyed tanks on the streets”. He blames the shipping company for the Ever Given’s problems. “They got greedy and kept on piling up the cargo until the vessel ran aground,” he said.

Milad Fahmy, owner of a sweet shop, said the drama over the Ever Given “demonstrated how important the canal is and how the whole world cares about it”.

Visiting the headquarters of the Suez Canal Authority in Ismailia on Tuesday, and thanking staff for their efforts to free the ship, Sisi remarked: “The crisis confirmed and underlined what we have always known which is the big and important role of the Suez Canal.”