A woman who floated 24 kilometres after falling off her sailboat near the B.C. mainland Wednesday has been released from hospital, and says she survived thanks to some help from a friend.

The 40-year-old woman says a seal, most likely a harbour seal, kept her company throughout her traumatic experience, until she was finally rescued.

Prof. Lance Barrett-Lennard from the Vancouver Aquarium believes the seal was likely just curious, but undoubtedly helped the woman survive.

"I don't think it matters what the seal's motivation was," he told CTV News.

"From her point of view, it was great for her morale. There's nothing like being in a terrifying situation like that and having an animal along side with you."

The woman, who swam for eight hours across Georgia Strait, near Vancouver, told rescuers she was minutes away from giving up.

"She told the hovercraft she was going to give herself another 15 minutes and then that was it," Coast Guard spokesman Mark Simpson said.

The 40-year-old woman was wearing only shorts and a sweatshirt when her sailboat ran aground near the mouth of the Fraser River and she tumbled off.

Vancouver Coast Guard Brian Wotten told CTV News the woman was lucky to have survived as she wasn't wearing a life jacket. "It's a miracle ending," he said.

She was pulled from the waters near Valdes Island, one of the Gulf Islands between the B.C. mainland and Vancouver Island, after being spotted by a passing sailboat.

Coast Guard Susan Pickrell told CTV News the woman was "shivering uncontrollably and severely hypothermic," but otherwise unharmed.

Hypothermia is a condition in which the body's core temperature falls as a result of exposure to cold. If not treated, it can be fatal.

Two other crew members who were sleeping in the boat's cabin were unhurt. They had been travelling from downtown Vancouver to Galiano Island. Just before dawn, one of them notified the Rescue Co-ordination Centre that the woman wasn't aboard their sailboat.

Gerry Pash, centre public affairs officer, said the woman was extremely lucky.

"The fact that it's summertime and also that it's the mouth of the Fraser River there, certainly helped things along in terms of her ability to survive,'' Pash said. "In the wintertime, it would have been very, very difficult.''

The water temperature in the strait at this time of year averages 17 to 18 degrees.

The woman isn't the first lucky survivor of an unexpected dip.

In 1993, building contractor Bob Lord fell over the side of a B.C. ferry. The Victoria resident floated and swam about 30 kilometres before he was spotted in American waters by an off-duty policeman out for a morning's fishing.

Rescue officials said Lord was lucky to survive in the 15.5 C water and may have been saved by floating through a warm current from the Fraser River, which empties into the strait south of Vancouver.

With a report from CTV's Shannon Paterson in Vancouver