There was a loud impact and noise before the ferry off a coast of South Korea began sinking, a passenger who had been rescued from the vessel told YTN news television.
One person has been found dead in the ferry wreckage, according to a coast guard official.
The president of South Korea, Park Geun-hye, earlier ordered all available vessels and special operations divers to the rescue operation.
More top news
The boxer said it was the "least he could do" and even donated the £30,000 shorts he wore in his last fight against Devon Alexander.
By Sunday it should become drier with spells of winter sunshine but temperatures will still remain on the cool side.
There was no White Christmas but here's a look at the best Boxing Day snow scenes.