Five New Brunswick boaters are lucky after a freak accident that saw their five-metre-long vessel sink after colliding with a whale in the Bay of Fundy on the weekend.

The group had been out observing whales from a distance in the Passamaquoddy Bay. They decided to turn in as it was approaching dusk at around 8:30 p.m.

The boat was about 2.5 kilometres from shore when a whale, likely either a finback or a minke, unexpectedly surfaced in front of it, throwing the people overboard.

They were in the water for about 20 minutes when a passing sardine carrier pulled them out as the boat was about to sink. Two of the boaters were treated in hospital for minor injuries.

Clifford Urquhart, the captain of the fishing vessel called the Michael Eileen, said the boat started sinking quickly when they arrived.

"Just the bottom of the boat was sticking out ... when we got the younger girl," Urquhart said.

"[When] her father [was] aboard, the boat had submerged and was gone, had sunk. I think they're lucky people. We came across at the right time, I guess."

St. Stephen RCMP Sgt. Bob McKnight said, given that no one in the boat had a life-jacket on, the timing of the rescue just before dark was crucial.

"All things considered, they were a fair distance off shore — 2.5 kilometres — and they're fortunate the vessel was in the area at the time it happened," McKnight said.

Whale rescue

While the boaters are fine, there is a concern about the condition of the whale that is still swimming in the Bay of Fundy.

A whale rescue team at Campobello Island hasn't observed any injuries among the whales in Passamaquoddy Bay.

Mackie Greene, who is with the Whale Rescue Team at Campobello Island, said the group began a search for the whale at dawn on Sunday over concerns the mammal may have been hurt in the collision.

"If there was a mark you could see it because with the dark skin, the blubber is white underneath, so it would have peeled the skin off. You would have noticed the mark," Greene said.

"So I don't think it hurt the whale. The eyewitness said he saw the whale keep on going."