SWIMMERS are returning to Silverstrand Beach in Sai Kung, where sharks killed an elderly man last year, after the installation of a shark prevention net. Chan Hon-lee from Kowloon City's Tung Tau Estate was yesterday in among dozens of families enjoying their summer holidays on the beach. ''We come to swim at this beach because it has a net and because it takes only 15 to 20 minutes to come here from our home,'' he said. Mr Chan nevertheless said he would not allow his two children to swim out too far. A lifeguard at the beach said the number of swimmers had increased this year. ''Of course it has increased. The shark prevention net has been set up and many people have moved into the new estates in Junk Bay,'' he said. But Lau Chun-wah, a newspaper vendor from Junk Bay, said although the net gave him a sense of security, he suspected sharks could swim under it. And his son Ka-ki, 10, said: ''If there really is a shark, we are in the hands of luck.'' The two-year experiment with shark prevention nets began in May at Clear Water Bay Beach, Silverstrand Beach and Kadoorie Beach in Tuen Mun. A year ago, a hair salon owner died after being attacked by a shark at Sheung Sz Wan in Sai Kung. Ten days later, an elderly man was killed at Silverstrand Beach, apparently by a rogue tiger shark.