What are locations of air cushion of Oriental Star and the South Korean ferry Sewol

Oriental Star, a cruise ship on itswaytoChongqing fromNanjing with 454 people on board, capsized on the Yangtze River in Jianli County, Hubei Province, China.
The sinking of the South Korean ferry Sewol occurred on April 16, 2014, en route to Jeju Island from Incheon. The ferry, carrying 476 people, mostly school students, capsized and sank not far from Jindo Island.

The two capsized ships floating on water because of air cushion.

My question:
What are locations of air cushion in the two ships?
Why titanic can not floating on water?

 

The compartments can hold air which provides buoyancy. Air cushions are on hovercraft, also called air cushion vehicles.... ACV

 

Thanks！
I want to know air pocket in the capsized ships.
Many capsized ships floating on water by air pocket，for example Oriental Star and the South Korean ferry Sewol. But the news did not tell us the location of air pocket.

 

look at the design of a ship and you will see multiple compartments.

 

For example，many people said cookroom is the place where often create a air pocket.