Aerial photo shows the rescue scene in the Jianli section of the Yangtze River, June 2. [Hubei Daily]

6. Is the vessel water-proof?

A crew member who worked at the lowest cabin on the Eastern Star when it capsized said after being saved, "I was prepared to get off work when the water suddenly flooded the cabin".

According to China's safety regulations on riverboats, the portholes under a ship's waterline have to be watertight, and those above the waterline can be movable.

There is no clear evidence to show that the cruise ship underwent watertight process.

7. Did the captain make the wrong move in emergency?

Zhang Shunwen, the captain of the Eastern Star, said before the ship lost its balance, he tried to jam the helm hard aport to set against the wind from the south.

A veteran captain told thepaper.cn that when the helm is turned hard suddenly, the ship risks tilting to one side, and tragedy may happen if the tilting is coupled with swaying caused by wind.

A professor of Shanghai Maritime University said the captain of the Eastern Star had done the right thing technically, but in reality, turning full helm can result in the tilting of the ship.