A family is grateful for the quick-thinking actions of a passing whale-watching group after a crabbing expedition on Cowichan Bay on Vancouver Island went horribly wrong.

Simon Pidcock, with Ocean EcoVentures, was out whale-watching with a couple of other people in an area fairly close to the mouth of the bay around 6 p.m. PT when he noticed something out of the ordinary.

"We saw this boat doing donuts and it just didn't look right so we went over and we investigated," he said.

"As we got closer, we saw that a man with a two-year old son was treading water, holding the two-year old son out of the water. Then, the boat was doing donuts about 20 to 30 feet (six to 10 metres) from them. It was pretty close to them, full speed."

If we hadn't come when we had, another five minutes, it would have been a very different situation - Simon Pidcock

Pidcock headed straight for the man and child and got them into the boat.

Then, he was alerted to a third person in the water — the man's brother.

"We got over to him and he was just about to go under and he didn't have much strength left in his arms," Pidcock said.

His crew got a rope under the man's arm and around his chest and dragged him into the boat.

"His lips were bright blue," he said. "If we hadn't come when we had, another five minutes, it would have been a very different situation."

5-year-old 'truly a hero'

In the midst of this, the boat — a five-to-six-metre-long aluminum vessel — was still making laps around the area going full speed.

Pidcock was told there was a five-year-old girl on board.

"We got fairly close to the boat and we started yelling at her to pull the red cord — the kill cord — which actually stops the motor. The boat was really tipped over and moving very quickly. It was amazing. She got up, pulled that cord and shut the boat off.

"She was obviously screaming and crying at the time. She probably didn't even know how everyone in the water was doing. When she pulled the cord, all of us in the boat started cheering and yelling ... We were pretty proud of her. It was a pretty amazing feat for a little five-year-old in that situation."

They got her into the boat, and Pidcock said he and his fellow crew members were able to get the family wrapped up in warm gear and flotation coats.

The Coast Guard was called out to help, but the family was rescued and brought to shore by a passing group of whale-watchers. (CBC)

They were only seven to eight minutes from the dock in Cowichan Bay, and Pidcock said he alerted the Coast Guard to arrange for an ambulance upon arrival.

The children were uninjured, but the adults were treated for mild hypothermia.

"I'm really glad that they're all OK and the kids are OK. The little girl's truly a hero for what she did."

Accidental ejection

Pidcock said he believes the group fell out when they accidentally hit the throttle on their outboard motor, while attempting to retrieve a crab trap.

"[Hitting the throttle] is a pretty swift reaction in a small boat like that, and it's pretty easy to get ejected out of it," Pidcock explained.

Pidcock said normally the captain wears the kill cord while the motor is running, but if you're pulling a crab trap with the motor running, you're likely not wearing the cord because you're moving around.

A Joint Rescue Coordination Centre vessel in Cowichan Bay was able to secure the boat shortly afterwards.

With files from Gian-Paolo Mendoza and All Points West