The sinking of a cargo ferry in Turkey's Bosphorus Straits closed the shipping lanes down overnight, creating a bottleneck of dozens of vessels.
The Bosphorus is one of the world's busiest shipping lanes
Emergency teams had to battle strong waves to retrieve seven gas tankers which floated free while the ferry's eight-strong crew were all rescued.
The tankers were loaded with liquefied petroleum gas, and there were fears of an accidental explosion.
Ships were kept out of the area as the tankers were hauled into shore.
The narrow waterway of the Bosphorus Straits is the only sea passage for tankers between the Black Sea and the Mediterranean.
Turkish authorities were unable to say on Sunday morning when they would be fully open again to shipping.
The roll-on-roll-off ferry sank at 2205 (2005 gmt) on Saturday, about one nautical mile (1.9km) off Istanbul, Turkish NTV television reports.
It took about 10 hours for emergency services to bring the tankers to safety, each of which weighed 22 tonnes (tons).
"We were lucky," said Baris Tozar, an official at Turkey's transport ministry, adding that every care had been taken to protect other shipping and the coastal area from a possible explosion.
One of the tankers was damaged but there was no danger posed by the gas which leaked.