A Novato lawyer shattered a record by swimming unprotected across chilly Lake Tahoe in 10 hours, 17 minutes. David Kenyon, 35, wore only swim trunks, goggles, a cap and a thick layer of sunscreen for the 22-mile-long swim. The previous record was 19 hours, six minutes set in 1955 by Fred Rogers. The records are kept by the Tamalpais Aquatic Masters swim team in Marin, of which both men are members. Kenyon is believed to be the first man since Rogers to make the swim without a wet suit. Others have broken Roger's record in past years, but they were wearing wet suits. Kenyon followed a 28-foot cabin cruiser during the swim, stopping every half an hour to eat a brief snack of cookies, sandwiches and fruit while treading water. The 5-foot-10, 188-pound Kenyon swims more than 50 miles a week. He prepared for the 60-degree lake temperatures by swimming from the San Francisco-Oakland Bay Bridge to the Golden Gate Bridge and from Berkeley to the Golden Gate during the winter.