A CHINA Coast Guard (CCG) ship blocked a Philippine research vessel and its escort ship on their way to conduct a hydrographic survey north of Bajo de Masinloc (Scarborough Shoal) in the Philippines' exclusive economic zone (EEZ) over the weekend.

Retired US Air Force Col. Ray Powell, director of SeaLight, a maritime transparency project that monitors and reports activities in the South China Sea, reported on Sunday that CCG 5303 was monitored just 35 nautical miles from the Philippines' coast early Sunday morning when it blocked the path of BRP Hydrographer Ventura and its Philippine Coast Guard (PCG) escort BRP Gabriela Silang to get to their assigned hydrographic research area north of Scarborough Shoal.

The interference by the CCG ship prevented the Philippine vessels from moving for eight hours.

At around 8:40 a.m., the BRP-H Ventura and BRP Gabriela Silang were able to continue to sail en route to the survey area north of Bajo de Masinloc, but CCG 5303 shadowed the mission, Powell said.

On Friday, April 12, the National Mapping and Resource Information Authority (Namria) released a navigational alert about the hydrographic survey to be conducted by BRP-H Ventura north of Bajo de Masinloc starting April 13.

Namria advised all ships or watercraft transiting the area where BRPH Ventura would be undertaking its survey to take note of the information and take the necessary precautionary measures at all times.

BRP-H Ventura was the same ship that was able to identify the location of the sunken MT Princess of the Stars in Oriental Mindoro last year. It also took part in the mapping of the Philippine (Benham) Rise.