A 21-YEAR-OLD fisherman was killed when a boat caught fire near the Ap Lei Chau reclamation early yesterday. Firemen found the body of Mr Wan Wai-hung inside the cabin of his father's fishing boat after they put out the blaze at about 6 am. Officers said it did not appear that the fire was started deliberately. The 22-metre fishing vessel was moored alongside other vessels near the reclamation area in Aberdeen when the fire occurred at 4.40 am. During the blaze there was an explosion of liquid petroleum gas cylinders on board the boat. Firemen and Marine Police cut the anchor and towed the blazing vessel away to ensure the fire did not spread to neighbouring boats. The boat owner, 42-year-old Mr Wan Chi-ming, had borrowed $500,000 from friends and relatives to purchase the second-hand vessel two months ago. Relative Mr Wan Fook-hei, said he, the boat's owner and Wai-hung, had just returned to Aberdeen on Wednesday morning after several days fishing about 80 nautical miles south of Waglan Island. ''After we came back, we went straight to the Aberdeen Fish Wholesale Market to sell our catch. Wai-hung remained on board the boat looking after things when we left the vessel at 5 pm,'' Mr Wan Fook-hei said. Wai-hung's mother, 37-year-old Mrs Wan Cheung Woon-ping, collapsed when she saw firemen carrying her son's body from the cabin. She was taken to hospital where she was treated and discharged. Wai-hung's uncle, Mr Wan Loi-fook said the vessel had not been insured. Wai-hung joined his father at sea four years ago. The family lives in a nearby public housing estate.