An experienced diver mysteriously drowned while snorkelling with friends, an inquest heard yesterday. To Fang-sam, 35, went snorkelling with two friends off Kat O, Kat O Chau, on June 4. The men snorkelled for 45 minutes and took a 20-minute break on a sampan before re-entering the water. But 15 minutes later To could not be seen, the court heard. He was found floating and his friend, Mak Wai-lam, tried to resuscitate him, but To died the same day in Eastern Hospital. Pathologist Shum Shing-fun said in a written statement to Coroner Paul Kelly that To drowned. He was also found to have a coronary artery 50 per cent narrower than normal. 'I cannot say one way or another [whether his narrow artery] affected his ability to stay under the water for a certain period of time,' said Mr Kelly, who recorded a verdict of accidental death.