A Marin County schoolteacher has become the first person to swim from the San Francisco-Oakland Bay Bridge to the Golden Gate Bridge and back. Suzanne Heim, 27, covered the 12 miles in 3 hours, 27 minutes. Heim, a high school special education teacher, called her swim a tune-up for a second attempt at the English Channel this summer. Heim crossed the English Channel last August in 10 hours, 11 minutes. She said it took her 1 hour and 43 minutes to reach the Golden Gate Bridge because "it was incredibly rough," and she was battling 20-knot winds. "As nice as it was on the bay, it was rough and cold with a big fog bank at the Golden Gate," she said after her feat. "That's where the water turned colder."