OWNERS and captains of ships using Hongkong - the world's busiest container port - are being warned to travel at full speed and to be prepared to fight off pirates responsible for a fresh spate of attacks in the South China Sea. The alarm was raised by the Marine Department and the Hongkong Shipowners' Association following a confrontation between a Royal Hongkong Auxiliary Air Force plane and a suspected pirate vessel 90 miles southeast of Hainan Island. Crew aboard a RHKAAF aircraft repeatedly ''buzzed'' the ship to keep it away from a Chinese freighter. The pirate's radar was working and it had a fast speedboat trailing behind it. Hours before the pirates were seen steaming towards the freighter, a group of them were believed to have strafed two large cargo ships with automatic weapons in what local shipping industry sources see as a new threat to Hongkong's status as the leading free port. The most serious of six attacks reported so far this year involved the shooting of a 46-year-old Filipino seaman by suspected pirates just seven miles off Waglan Island on Monday night. He was shot in the back from a fishing boat which moved in close to the Panamanian-registered Marine Peace. The seaman was in satisfactory condition at Queen Mary Hospital last night. This week's attacks prompted Marine Department action to ensure ships travel at full speed through the area with crews ''awake and alert''. The Hongkong Shipowners' Association warned its members to dangle bright lights from their ships to dazzle potential raiders. Senior Marine Officer (port formalities), Mr Trevor Berry, said the department's message, cabled to Tokyo, Singapore and Taiwan, also advised captains to have fire hoses at the ready to keep pirates at bay. ''I've certainly never heard of attacks in this area before and we want everyone to be aware of the possibility,'' he said. ''As they [pirates] come over the side, the fire hoses at least give you the chance to defend yourself and you don't have to get close to them.'' RHKAAF Flight Lieutenant Bob Patrick said after being alerted by the Marine Department he flew his aircraft down to just a few dozen metres as it buzzed the ship believed to be responsible for the two raids. ''We saw the suspect ship and noticed it was steaming towards a Chinese vessel called Liaocheng,'' Flight Lieutenant Patrick said. ''We buzzed him a few times and got in quite low. I think it certainly deterred him from going closer to the Liaocheng. We were making him aware that he was being watched and we could react if he tried anything.'' Marine Department officials alerted the crew after rescue centres in Kuala Lumpur and Okinawa reported distress calls from two ships at 9.20 am and 10.30 am on Tuesday in the same area. The Panamanian-registered Mary Nour and Turkish-registered Ayse Anak both reported on Tuesday that they were fired on by about eight seamen wielding automatic weapons. The ships were last night continuing to Singapore and Bangkok respectively. The sailors from the fishing vessel used a speed boat to pull alongside. Mr Berry said reports suggested the men were dressed in ''quasi-military'' uniforms of green shirts and white T-shirts. The RHKAAF plane arrived on the scene, near the limit of its range, in an hour and 45 minutes. ''As we came down we noticed directly ahead several fishing boats,'' Flight Lieutenant Patrick said. ''But there was one which stood out particularly. This vessel was towing a small dinghy with an outboard motor.'' He said he then decided to try to find the Mary Nour which was heading towards Singapore. ''We obtained a brief description of the pirate vessel from the captain of the Mary Nour who told us what happened. That tied in every detail with the boat we had previously seen.'' He added that reports from the captain that the pirate ship had sailed northbound initially confused the aircrew, but they soon became aware that the suspect vessel had made a U-turn. ''We tried to raise the radio room on the Liaocheng and our Warrant Officer Kennedy Wong spoke to him in Cantonese and took pictures of the whole incident.'' The aircraft was forced to head back for Hongkong after about an hour because of dwindling fuel supplies, he said. Meanwhile, Shipowners' director, Mr Michael Farlie, praised the Marine Department's swift response in sending out the message, but said he took further action to ''refine'' the warning. ''We have learnt through bitter experience in the Malacca Straits and off Singapore that simply illuminating a ship only provides a better target rather than a deterrent,'' he said. ''They seem to think that by firing a few shots they will show enough authority to make the ship stop. Maybe they're rank amateurs or simply so arrogant that they think no one will take action against them.''