BOSTON (CBS) – Dozens of swimmers, including three former Olympians, jumped into Boston Harbor Friday morning for a good cause. The 23rd annual Boston Harbor swim helps kids battling cancer.

About 50 wetsuit-clad swimmers hit the water at Rowes Wharf at 7 a.m. and proceeded to power through a 22-mile open-water relay, in the rain at times.

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The yearly harbor swim raises money for Dana-Farber Cancer Institute and Mass General Hospital for Children.

Leading the way in this year’s Swim Across America event were Janel Jorgensen McArdle, who took home a silver medal in the 1988 Seoul summer Olympics and now travels the country for various Swim Across America events, 2012 Olympian Alex Meyer, and 1996 Olympian Eric Wunderlich.

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“For me it was all about being able to leverage the sport of swimming to give back,” McArdle said.

“It’s not fun in the rain,” admitted swimmer Stephen Colbert, a cancer survivor who also lost his brother to cancer. “It’s just such a warm great group of people that all truly are swimming for something.”

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Each participant swims 15 minutes at a time, several times throughout the day. The relay takes about 8 hours to complete. McArdle said this one event raised about $325,000.