Four women will brave the shark infested waters of the San Fransisco Bay, battle rough currents, high waves and passing boats — and plan to do it all in the name of charity.

Bermuda residents Jo Turner, Anne-Marie deGraft-Johnson, Sula Bancroft and Rajah Abusrewil will take the plunge on June 6 after six months of training to raise money for charity.

They will be dropped off by ferry at the infamous Alcatraz Island, which housed a high security prison, and swim 1.5 miles to the finish line.

Ms Bancroft, who along with Ms Abusrewil is raising money for Macmillan Cancer Support, said: "Basically what we are going to do is go to San Fransisco and go out in a ferry to Alcatraz, then hop off into the freezing cold water and swim back".

It was a friend who encouraged Ms Bancroft to take part in the challenge, but she didn't have the faintest idea what it entailed. She did, however, think it would be a great opportunity to do something good for charity.

Though she was a fair swimmer before taking on the adventure — known as Sharkfest — she soon realised that fighting against mother nature was a whole different challenge.

But in San Fransisco, she will have to swim in 55 degree Fahrenheit waters five degrees colder than normal for this time of year. She will also have to consider sharks and sea lions lurking beneath her in the bay.

Still the benefits outweigh the potential dangers for Ms Bancroft, a veterinary nurse at Ettrick Animal Hospital, who has been living on the Island since February last year.

So far the duo has raised close to 1,000 British pounds and an additional $800, and hopes to get the total a little higher before the big day.

* If anyone wishes to support the women on their charity swim they can visit: http://www.justgiving.com/Sula-Bancroft to donate in pounds sterling; or http://www.firstgiving.com/sulabancroft to donate in dollars.