PASSENGERS on high-speed night ferry services to Macau were reassured by the Marine Department after a report on a collision off the enclave in which 49 people were injured. The collision, between a jetfoil and a tugboat towing floating pipelines, was caused by inadequate illumination of the pipelines, the report concluded. Director of Marine Allan Pyrke promised ''mitigating measures recommended by the investigation will be implemented to help prevent a repetition of incidents of this nature''. A re-enactment of the collision revealed that floodlights mounted on the tug failed to illuminate the pipelines because they were travelling half-submerged in rough waters. If the pipelines had been lit as required by international regulations, they would have been visible to the jetfoil's bridge team and would also have been detected by its visual augmentation system (VAS), the report said. VAS, consisting of a low-light television camera and an infra-red searchlight, improves night vision. A copy of the report will be sent to Guangdong Harbour Superintendency, which conducted its own investigation, said Mr Pyrke. Guangdong authorities will determine whether the tug's skipper will be prosecuted. The collision, which occurred about four nautical miles off Macau shortly after 8 pm on July 11 last year, resulted in injuries to 49 of 264 passengers aboard the Hong Kong-bound jetfoil Urzela. The jetfoil returned to service in January after being dry-docked for six months for repairs to its hull. Three sections of the pipelines were damaged beyond repair. The tug, Hang Feng 901, was towing two 110-metre lengths of pipeline from Guangzhou to the Macau airport works site. International regulations require white lights visible from at least three nautical miles to be displayed at the end of the towed load and mid-way if the length exceeds 100 metres. Lights fitted to the pipes were apparently not working as the Guangzhou-registered tug approached Macau and floodlights trained on the load failed to illuminate the submerged load. The Marine Department will ask masters of all vessels to take extra care at the approaches to Macau harbour during construction of the Macau airport, said Mr Pyrke.