There were several occurrences of bunker tankers running aground within the vicinity of Singapore anchorages. Notwithstanding ship handling skills, Masters’ assessment of root cause pointed towards the state of strong current and wind.
Case study 2(a) – Visual navigation and grounding incident
B casted off from a bunker receiving vessel in the vicinity of Senang buoy and headed toward Raffles Petroleum Anchorage (RPA). B’s gyro compass was not working properly hence causing abnormal function of her radar simultaneously. Unable to use the radar, the master saw one of his company’s vessels (CV) anchored at RPA and decided to visually navigate B by referring to CV. He took a magnetic bearing of CV and continued to steer B to head CV at the same magnetic bearing, around North Westerly. The master confirmed that he was aware of the prevailing current and wind conditions, i.e., both elements were pushing B to her port, i.e., current set at 247° (T) with 1.0 kts drift, increasing; with 20 kts wind from Northeast. B eventually grounded, 12 minutes after casting off from bunker receiving vessel. See Figure 1 below.
Case study 2(b) – Gut feel and grounding incident
C weighed anchor in Raffles Petroleum Anchorage (RPA) and heading for Sebarok beacon to pick up pilot. The master made a ‘U’ turn to head for Sebarok beacon. C’s echo sounder, in digital readout was never switched off and not referred to timely.
The master was aware of the prevailing current and wind conditions, i.e., pushing C towards her starboard or north-easterly direction.
The master decided to turn to starboard because C’s drafts were light: DF 1.5m, DA 2.5m. He felt that the current of 1.1 kts was not effective on C’s drafts.
Hence, his decision to turn C to starboard to make the ‘U’ turn. C went aground 5 minutes after anchor aweigh. See Figure 3 on the right.
Why did it happen?
Both grounding incidents happened within the same vicinity. The weather conditions were similar at the material time. In both cases, masters had not appreciated the strong current and wind weather conditions. Instead of steering the vessels based on course made good, both had concentrated on their respective vessel’s heading. In case study 2(b), both current and wind were pushing his vessel from the port and the master turned his vessel to the starboard, which assisted her grounding (see Figure 3, above).
Commentary
It was noted that in most cases, despite the requirements of having additional bridge team member(s) on the bridge as per company’s safety management system (SMS), navigation was usually carried out by the master alone.