Rescue crews are in their second day of searching the St. Lawrence River for a missing boater.

Around 8 a.m. Monday two men boarded a small boat and began to cross the St Lawrence River to retrieve a fallen drone when the vessel capsized about 60 metres from Devil's Island. The boat then went over the Lachine Rapids.

The driver of the boat spent about 45 minutes floating in the water before he was rescued by somebody in another pleasure craft near Nuns' Island.

He was taken to hospital to be treated for hypothermia.

The other man was not wearing a life jacket and has not been seen since.

Both men are in their 50s.

Montreal and Longueuil firefighters were some of the first patrolling the river in several boats, but they pulled back from the operation as the Coast Guard became involved.

The Coast Guard used boats and helicopters to search the water between Saint Catherine and Lafontaine Tunnel on Monday, and continued to search on Tuesday.

Life jackets required: Quebec Lifesaving Society

There have been at least 30 drowning deaths in Quebec this year, a 20 per cent increase from the same time last year.

According to the Quebec Lifesaving Society, one of the reasons for the increase is that 10 of the drownings occurred in rivers with high water levels.

Many people underestimate how rough water can be, even when boating, and that can end in tragedy.

"Always have a life jacket," said Raynald Hawkins, director of the Quebec Lifesaving Society. "It makes a huge difference."