The Philippine Coast Guard and its salvage response partners have been making progress on preventing pollution from the sunken tanker Terra Nova, which went down in rough weather from Typhoon Gaemi on July 25.
Terra Nova has an estimated 370,000 gallons of petroleum on board, and has leaked an unknown but substantial amount of its oil into the bay. However, the PCG says that the leakage is now largely under control. As of August 1, all of the valves and high-level alarm pipes to the ship’s cargo tanks have been capped, and a work barge and a receiving tanker have been positioned at the wreck site in preparation for siphoning off the remaining cargo. Only a thin sheen is present at the site, the PCG said, and there are control measures to keep it contained, including booms, dispersants and skimmers. Satellite tracking provided by the University of the Philippines Marine Science Institute shows that the size of the spill area coverage has been shrinking significantly.
Over the next two weeks, the PCG and its commercial salvage partners will improve on the containment measures currently in place, before siphoning begins. PCG Commandant Admiral Ronnie Gil Gavan said that the capping bags that salvage divers used initially to prevent oil from getting out of the tank vents will be replaced by new metal caps. It will take about seven days to fabricate the caps, and another seven days to install them. In the meantime, divers will replace all the capping bags with a new set in order to reduce the risk that any might get punctured and leak.
“With the above developments, the siphoning will be moved to not later than two weeks from now. This due diligence measure will however afford us with better control to reduce to barest minimum the possibility of disastrous oil spill during the conduct of siphoning activity,” Gavan said.
Once the team has siphoned off enough oil, they plan to refloat the vessel and move it to shallower water. That process should take another week, the PCG told local media.
The United States Coast Guard and the National Oceanic and Atmospheric Administration (NOAA) are providing technical assistance for the response, including a seven-person advisory team, according to the PCG.
On July 24, Terra Nova was under way and heading out of Manila Bay, bound for Iloilo with a cargo of fuel oil. At about 2200 hours, as the small tanker neared the entrance to the bay, it encountered heavy waves from Typhoon Gaeli. The captain tried to turn the vessel around, but the tanker capsized and sank four miles off Lamao Point. One tanker crewmember was killed the sinking, but 16 were rescued in a daring PCG SAR operation, earning the crew of a PCG response cutter a commendation for bravery.
Reference : https://maritime-executive.com/article/philippine-coast-guard-brings-tanker-spill-under-control