The kayak accident happened around 3 p.m. Saturday in Jamaica Bay.
From a helicopter, divers Detective Brian Singer and Police Officer Marian Kopystianskyj want into the water and retrieved one kayaker.
Meanwhile, Detective John Kenny was monitoring police radio traffic and went to the area. He saw a second man swimming to a boat anchored in the bay.
Kenny put on his police-issued wetsuit and swam 200 yards to the boat.
Water temperatures around New York Harbor are currently around 40 degrees. The 32-year-old kayakers and Kenny were treated for hypothermia and are in stable condition.
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