The only child of a fireman who went missing in rough surf as he tried to rescue a drowning boy, yesterday refused to give up hope that his father was still alive. Chiu Shun-on's 13-year-old son shouted for his father to come back as the boy's mother and other family members waited on Tai Long Wan Beach, Sai Kung, watching the search. The boy said his father was a brave man and he thought he had a 50-50 chance of being found alive. Mr Chiu, 48, was washed away on Tuesday when he tried to rescue Wong Wing-nam, 15. Another off-duty fireman who was hiking with Mr Chiu also dived in and made it back to shore, but the boy was washed up dead. 'My father can't swim very fast but he can swim for a long time and he is tough. I believe he might survive,' Mr Chiu's son said. The teenager yesterday comforted his distraught mother, telling her his father might have been washed up on an outlying island where he could be waiting for help. Mr Chiu's son used a branch to scratch a poignant message in the sand: 'Don't waste any time because time is such an important thing.' As his mother and relatives burned incense and paper offerings, the schoolboy shouted out the name of his father and said: 'Please come back or give us a signal.' Other relatives wept as they watched the search. Dozens of off-duty firemen, including colleagues of the missing man, joined the air, land and sea search when it resumed at about 6am yesterday. Two helicopters from the Government Flying Service were sent out in the morning and a fixed-wing plane was deployed in the afternoon when the area to be covered in the search was extended. Ken Wong Tang-kin of the Government Flying Service said they had expanded the search to Mirs Bay, also known as Dapeng Wan, near the border. 'We are worried that Mr Chiu would have swum to farther places,' he said, as poor visibility hampered yesterday's search. 'The plane flew down to three hundred feet [90 metres] above sea level. The worse the visibility, the harder it is to spot the survivor,' he said. The commander of the Fire Services Diving Team, Divisional Officer Tsui Hon-wing, said three teams of divers conducted an overnight search and teams of officers patrolled the coast. He said the department would consider recommending that the SAR Government honour Mr Chiu with a bravery award to acknowledge his attempted rescue of Wing-nam. 'Right now we are focusing on finding our missing fireman,' he said. Acting Director of Fire Services Lam Chun-man said the actions of Mr Chiu had been commendable. He said the rescue team would make every effort to find him. The Secretary for Security, Regina Ip Lau Suk-yee, also commended Mr Chiu for his bravery. Fire Services workers were planning to search all night.