Giant vessel shuts the Bosphorus

A Turkish woman watches as the Varyag passes

Turkey has temporarily closed the Bosphorus Straits - which is one of the world's busiest waterways - to allow the passage of a huge vessel.

Tugboats hauled the giant aircraft carrier Varyag through the narrow and treacherous straits, as crowds of sightseers lined the shores.

The Bosphorus narrows to around 700 metres at one point. And in six different places you need to change course by about 30 to 40 degrees. There is a real threat, it's a risky passage

Istanbul Shipping Rescue office

The 300-metre Varyag waited for 16 months to pass through the narrow straits on its way from Ukraine to China, which wants to convert it into a floating casino.

The Turkish authorities had refused to let the 55,000 tonne vessel through on safety grounds, and agreed only after the lengthy negotiations with China.

Floating danger

The Bosphorus has a reputation of being one of the world's most dangerous waterways.

There have been some 200 accidents over the last decade in the 34km straits, which links the Black Sea to the Mediterranean.

Turkey feared the vessel might damage Istanbul

The Turkish authorities argued that the Varyag would have considerable difficulties to navigate the straits' tight curves.

They said, that together with its tugs, the vessel would be too long to safely pass the Bosphorus.

"The Bosphorus narrows to around 700 metres at one point. And in six different places you need to change course by about 30 to 40 degrees," said Aslan Dede from Istanbul state-run Shipping Rescue office.

"There is a real threat, it's a risky passage," he added.

Turkey also insisted that the Varyag would pose too great danger to bridges, palaces and homes in Istanbul.

The Bosphorus bisects Turkey's largest city, which is a home to more than 10m people.

The Bosphorus and Dardanelles straits are governed by Turkey under the 1936 Montreux treaty, which guarantees all commercial ships the right of free passage.

The deal

The Varyag received the go-ahead in August after China and Turkey finally made a deal.

China said it would minimise the potential security risks and compensate Turkey for any possible damage.

The deal also included a tourism agreement and trade concessions by Beijing.

The Bosphorus

34km long

3,500 ships pass monthly

440m barrels of oil travel each year

200 accidents over last 10 years

But the decision has angered Turkish environmentalists.

They say that the Varyag's passage will set a precedent for other vessels that are oversized or carrying dangerous cargoes.

"Shooting casino"?

China paid Ukraine $20m for the half-built aircraft carrier.

Beijing says it wants to convert the Varyag into a pleasure palace of casinos, restaurants and hotels.

But some experts have expressed doubts about China's intentions.

They say China wants the technology to build its own aircraft carrier to strenghten its Navy in the Pacific.

However, military experts say the rusty Varyag would offer relatively little to China for any projects of its own.