'He was looking right up at us:' Retired Canadian navy captain on aftermath of Danube sinking

If it weren't for the city lights of Budapest, Canadian tourist Ken Hoffer says he wouldn't have spotted the man in a life preserver rushing down the Danube River.

The retired navy captain from Halifax hopes that chance sighting helped authorities locate the man and other survivors of a deadly crash between two ships on the river.

"He was looking right up at us. I think he was trying to raise his hands," Hoffer told CBC's Maritime Noon. "I think he might have been right on his last legs."

Seven people are confirmed dead and seven were rescued after the sightseeing boat Mermaid, which was carrying South Korean tourists, sank on Wednesday night following a collision with a larger cruise ship. Rescue workers searched for 21 missing people kilometres downriver on Thursday.

"All I saw was the glow of his face," said Hoffer, who had trouble seeing in the pouring rain.

"If they didn't have city lit up like the 4th of July there's no way we would have been able to see him."

About 20 minutes before, the crew on Hoffer's boat, the Avalon Illumination, told passengers another vessel had sunk and they'd have to slow down. The water temperature was between 10 to 12 C and by that point hypothermia may have set in, Hoffer said.

Deck chairs, floating seat cushions and empty preserver rings were in the water, but no life jackets, said Hoffer. Moments after spotting the first man, Hoffer saw a second man in a ring.

Hoffer alerted the crew of the Avalon Illumination, who called police boats in the area over to the debris field, which was between the Elisabeth and Chain bridges, about three kilometres downriver from where the sunken boat was found Thursday near the Margit Bridge.

Police Col. Adrian Pal said the Mermaid turned on its side and sank in about seven seconds. He said rescue operations were hampered by the rain and the fast flow of the rising Danube.

"It was really a very surreal sight," said Hoffer. "I like to think I played some valuable role in helping get the police and the other patrol into that area to start looking for survivors."

He is hopeful the two men he found were among those rescued.

Nineteen South Koreans and two Hungarian crew members are missing. The tour party had consisted of 30 tourists, two guides and a photographer on a package tour of Europe.

Police have launched a criminal investigation.

Dozens of personnel searched far downriver into Serbia on Thursday.