A Dragging Anchor Incident Results To Collision

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  • Dragging anchor caused a general cargo ship to collide with two nearby ships, resulting in structural damage to all three ships.
  • Effective communication plays a pivotal role in maritime safety. In the event of engine readiness challenges, timely communication could enable nearby ships to take precautionary measures.
  • Ensuring a strong communication protocol is in place allows for the distribution of crucial information, reducing contact or allision risks and fostering a safer maritime environment.

Britannia P&I Club released a case study focusing on an incident in which a dragging anchor caused a general cargo ship to collide with two nearby ships, resulting in structural damage to all three ships. Fortunately, no pollution or loss of life was reported.

What happened

A 2,840 gt general cargo ship (ship A) embarked on a journey from Groveport, England, to the Holme Hook anchorage on the River Humber for bunkering. The ship was under pilotage and in ballast condition. The ship had recently lost its port anchor due to heavy weather, and a replacement anchor was yet to be fitted. Therefore, the ship’s classification society had issued a Condition of Class (CoC) requiring it to keep its main engine on standby while at anchor. While the ship was navigating upriver to the anchorage area, the weather conditions were deteriorating. Around the same time, a ship from the same company (ship C) experienced anchor dragging at Hawke Anchorage and only managed to hold its position by dropping an additional shackle of cable into the water. The attending pilot advised the master on ship C to also keep the ship’s engine on standby.

Meanwhile, ship A arrived at the Holme Hook anchorage initiating its anchoring procedures. However, due to adverse weather, the planned bunkering operation was aborted, and the master was advised by the local Vessel Traffic Services (VTS) to anchor at the Hawke anchorage. Before leaving Holme Hook anchorage, the master of ship A noticed his ship had also dragged anchor.

Ship A then proceeded to the Hawke anchorage and anchored at around 23:00. Prior to disembarking, the pilot advised the master to remain vigilant, and to keep the ship’s engine on standby. However, soon after the pilot disembarked, the master ordered to stop the engine and handed over the bridge anchor watch to the second officer without any specific instructions to be alert of the weather situation. Upon assuming the watch, the second officer went on to complete administrative tasks. At this point, a research and survey ship (ship B) was anchored three cables to the northwest of ship A.

At 02:46, ship A started dragging anchor however, the second officer failed to recognise this until nine minutes later. The second officer notified ship A’s master immediately and the duty engineer was called to start the main engine. The duty able seaman was then directed forward to inspect the anchor cable. The chief officer took over watch from the second officer at 03:00 and the second officer went down to hasten the engineer. Ship B cautioned ship A on Very High Frequency radio that it was dragging anchor directly towards ship B. Ship A acknowledged the call and informed ship B that they were preparing to start their engine. Thereafter, the bridge watchkeeper on ship B also instructed their duty engineer to start the main engine and informed the master of the situation. Humber VTS also transmitted a warning to both ships and enquired on their current engine readiness situation.

Despite ship A’s attempts to start the main engine and utilising its bow thruster for avoidance, the collision occurred at 03:12, with ship A’s stern colliding with ship B’s bow. Following the collision, ship A managed to start its main engine. However, the vessels remained entangled due to ship B’s anchor chain and attempts to disentangle were complicated by wind and tidal forces, causing the entangled vessels to drift towards Ship C, anchored nearby.

Watchkeeping

The handover of the bridge anchor watch failed to provide crucial information, including the position monitoring frequency, and the need to monitor changes in wind and tidal stream strength. Given the prevailing circumstances, watchkeeping responsibilities required immediate attention and focus, prioritising vigilant monitoring of the position due to potential risks. Administrative tasks should be delegated or postponed. To improve future incident prevention, consider adopting a more frequent and vigilant monitoring interval for anchor positions, along with utilising Global Positioning System (GPS) anchor alarm aids. Implementing a shorter and tighter monitoring schedule could aid in early detection.

Proper anchoring procedure

In the event of a dragging anchor, established procedures should include immediate reporting to the master, contacting the engine room/duty engineer to prepare the main engine and any other required machinery, and readying the windlass with the designated anchor party. It is also important to ensure the bridge is sufficiently manned as required (helmsman and lookout). Furthermore, when applicable, deploying additional cables, notifying other vessels in the anchorage, as well as informing the port authority becomes crucial. This ensures adequate reaction time not only for the ship experiencing dragging anchor but also for ships in the vicinity, as the situation may escalate quickly. These steps should form the backbone of established procedures, with the readiness level of both the main engine and the anchor party predetermined by the master. This decision should be based on factors such as the likelihood of dragging and nearby navigational hazards. The Safety Management System (SMS) should support the master by providing clear guidance on readiness levels and the allocation of crew resources.

Effective communication

It was also observed ship A did not promptly alert other ships in the vicinity or VTS about its situation. Effective communication plays a pivotal role in maritime safety. In the event of engine readiness challenges on ship A, timely communication could enable nearby ships to take precautionary measures. Ensuring a strong communication protocol is in place allows for the distribution of crucial information, reducing contact or allision risks and fostering a safer maritime environment.

Company procedures and main engine readiness

Ship A’s master directly contradicted the CoC issued by halting the engine shortly after the pilot disembarked, despite the requirement for the main engine to remain on standby while the ship was at anchor. This decision may have been influenced by an inconsistency in the fleet’s approach to engine readiness, as it was not defined in the ship’s SMS, leaving it open to interpretation. Although it is commonly accepted that this encompasses the main engine being immediately ready for manoeuvre, the lack of explicit guidance in the SMS allowed for varied interpretations. In cases where a CoC or other temporary operational restrictions are imposed on a ship, it is important to update the onboard SMS to reflect such restrictions and provide clear guidance to the master. Once the restrictions are lifted, the SMS should be returned to its original form, as applicable. Both ship A and C were promptly informed about the forecasted weather conditions, predicted tidal stream, and the congestion at the anchorage. However, a distinct discrepancy in their approach to engine readiness raises concerns and highlights a potential gap in company guidance. This lack of uniformity raises questions about the effectiveness of the company’s guidance and underscores the need for a more standardised and comprehensive approach to engine operations under similar circumstances.

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Source: Britannia P&I