SAN FRANCISCO (CBS SF) — A group of Bay Area swimmers is attempting a difficult feat Thursday: swimming roughly 30 miles in frigid, shark-infested waters with no wetsuits – and all in the name of charity.

The swimmers kicked off their swim from the Farallon Islands Thursday morning around 6 a.m. and hope to reach the Golden Gate Bridge Thursday evening around 7 p.m.

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Six swimmers registered to take part in Thursday’s event, U.S. Coast Guard Lt. j.g. Allison Natcher said.

“It’s a relay, with one swimmer in the water for each hour continuously,” Natcher said.

The relay is taking place in what is known as the Red Triangle, an area off the coast of San Francisco known for its abundance of marine life – including great white sharks.

The water temperature is a little over 50 degrees, but the athletes will only be clad in goggles, swim caps, and swimsuits.

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The participants, who are part of the Night Train Swimmers group, attempted the same relay in June 2010, but were forced to call it off when one of the swimmers began to experience hypothermia, Natcher said.

Night Train Swimmers consists of 12 athletes dedicated to raising money for charity through long-distance swimming events.

Money raised by Thursday’s event will go to organizations that benefit members of the military, their families, and veterans, including Wounded Warrior Project, Semper Fi Fund, and the Navy Seal Foundation, according to the group’s website.

The group was created in 2008 when five members swam across the English Channel, and its membership has grown every year since, according to the website.

Those interested in observing Thursday relay from a safe distance can follow Night Train Swimmers on Twitter and track their progress in real time at

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