Four years ago, when the Korean warship Cheonan was sunk, it took one month to lift it from the ocean floor, and it weighed just one-fifth of what the Sewol-ho does.
The passenger ferry, at more than 68-hundred tons, is one of the largest operating in the nation.
One-hundred-eighty vehicles and cargo weighing 12-hundred tons were onboard when the ferry departed Tuesday evening local time.
Add that to the water that has since inundated the ferry, the total weight that the cranes will have to lift easily exceed 10-thousand tons.
Four cranes with capacity of 10-thousand tons combined have approached near the waters of the sunken site and are on standby.
But the government says the lift will not be carried out without the consent of families of the missing, as shifting the vessel could jeopardize the safety of possible survivors, who at this point would have to be relying on "air pockets" to stay alive.
The ferry must be turned upright first in order to be lifted to minimize further damage and to stabilize the lifting process.
Divers will fasten cable wires underwater to the vessel to lift it, but authorities say the lack of experience in lifting a vessel of this size along with fast currents and poor visibility could delay the process.
Song Ji-sun, Arirang News.