AIS Transmission Failure Led To Bulker Collision



On 17 May 2017, Gortynia, a fully laden cape size bulk carrier, collided with bulk carrier DZ Qingdao in Singapore Strait. The collision occurred in the East-bound deep water route of the traffic separation scheme (TSS) off Batu Berhanti.

Gortynia sustained major damage to her port side forward ballast tanks both above and below the waterline. The vessel also sustained varying degrees of damage to the port side hull and deck fittings from cargo hold no. 1 to just forward of the accommodation. DZ Qingdao also sustained major damages to her bow. Both vessels were able to proceed to an anchorage, off Singapore where the respective damages were assessed.

The safety investigation concluded that prior to DZ Qingdao suffering a power loss resulting in a temporary loss of propulsion and steering, both vessels were approaching each other in their respective traffic separation lanes and were to pass clear of each other. The change in DZ Qingdao’s heading and speed meant that she now was at risk of collision with Gortynia as they approached each other. This change was not noted on board Gortynia as the bridge team were only monitoring AIS targets on its radars, and with the loss of power on board DZ Qingdao, the AIS transmission ceased, causing the loss of the AIS plot. DZ Qingdao did not warn VTIS and the surrounding vessels that she was not under command and as a result when the change in heading was detected by Gortynia, at a very late stage, this did not allow her to take effective avoiding action in time to avoid the collision.

The Marine Safety Investigation Unit (MSIU) has made a number of recommendations to Eastern Mediterranean Maritime Ltd, the managers of Gortynia, aimed at addressing safety of navigation on board vessels under its management.

During the course of the safety investigation, the MSIU had very limited information on DZ Qingdao, her crew members and the dynamics leading to the collision with Gortynia. To this effect, the MSIU was unable to analyse and report on a more detailed operational context and perhaps enhance the possibility of preventing similar future accidents by making recommendations to the managers of DZ Qingdao.


Damage to Gortynia

Gortynia sustained extensive damage to her hull in way of port side ballast tank no. 1, which included:

  • breach of the upper topside tank and double bottom (Figures 15 and 16);
  • cracks in the side shell plating, in way of cargo holds nos. 1 and 2;  
  • buckling of the shell plating and fish plate extending from frames nos. 41 to 263;  
  • deformation of web frames in way of the above mentioned damage;  
  • damage to deck railings and fittings at various locations (port side);  
  • damage to the hatch cover opening railway (port side);  
  • damage to various ballast and fuel oil tanks vent heads; and  fuel oil hose handling davits (port side).

Damage to QZ Qingdao

The exact extent of damage sustained by DZ Qingdao is not known. However, judging from the angle at which both vessels collided and the section of bow, anchor and anchor chain found on board Gortynia (Figure 17), the damage was extensive.


Findings and safety factors are not listed in any order of priority

Immediate Safety Factor:

  1. The perception of the developing situation which the crew members on the bridge of Gorthinia had, did not reflect the situation outside the bridge window. .
  2. When VTIS advised DZ Qingdao that they were entering the deep water route, instead of advising the Centre and the surrounding vessels that she was not under command, the crew members acknowledged the transmission thereby suggesting that the vessel was under control and that she would take corrective action.

Latent Conditions and other Safety Factors:

  1. DZ Qingdao was a vessel not under command but did not display the appropriate signals;
  2. Following the total power failure on board DZ Qingdao, Gortynia’s bridge team was neither unaware of the risk of collision which had developed with a vessel that was initially going to pass clear, nor of the immediate avoiding action which was required to avoid the two vessels from colliding;
  3. The bridge team thereafter did not continue to monitor DZ Qingdao’s track after the vessel was visually sighted;
  4. The AIS vector disappeared at around but this was not investigated;
  5. DZ Qingdao’s track trail distinctly indicated on the radar screen that the vessel’s heading had changed but this was also not investigated by the crew members;
  6. Distinct change in the aspect of the vessel and a transition in the navigation lights side lights, from red to green were also not investigated by the bridge team;
  7. Gortynia’s bridge team only became aware of DZ Qingdao when they heard a sound signal emitted by her at a very close range of about six cables;
  8. The reasons for the missed information was distraction;

Other Finding

  1. Fatigue and alcohol were not considered to be a contributing factors to this collision.


  1. review the lessons highlighted in this investigation and circulate to all vessels in the fleet;
  2. review the procedures on collision avoidance and reinforce the requirement of radar plotting by ARPA rather than reliance on AIS;
  3. review the procedures on collision avoidance and reinforce the requirement of radar plotting by ARPA;
  4. review their bridge team management and training in light of the findings highlighted in this investigation;  
  5. undertake a series of navigation audits on board its managed vessels to ensure company bridge requirements and procedures are being carried out.

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Source: Transport Malta


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