UK Marine Accident Investigation Branch (MAIB) has published an investigation report on the collision between the fishing vessel Kirkella (H7) and harbour tug Shovette resulting in pollution at King George Dock, Hull, England on 24 June 2022.
The incident
On 24 June 2022, while alongside at King George Dock, Hull, England, the crew of the UK registered fishing vessel Kirkella lost control of its propulsion system and the vessel collided with the unmanned tug Shovette, which was moored ahead of Kirkella. During the collision Shovette’s hull and starboard fuel tank were breached by Kirkella’s bulbous bow. The tug partially sank, which resulted in pollution of about 7,000 litres of marine diesel oil being released into the dock. Kirkella was not significantly damaged and there were no injuries. The investigation found that the pitch levers for Kirkella’s propulsion control system were mismatched between the bridge and engine control room when control was transferred. The classification society’s interpretation of the requirement that the control system should prevent the propulsion from altering significantly when transferring control between stations allowed the pitch levers to be mismatched when changing control from the bridge to the engine control room.
Kirkella’s operating company, UK Fisheries Ltd, has introduced measures to help stop a reoccurrence until the system can be retrofitted with prevention interlocks. The vessel’s classification society, Det Norske Veritas, has been recommended to propose to the International Association of Classification Societies that it reviews its Unified Requirement for remote control of propulsion systems. The system support company, Kongsberg Maritime, has been recommended to issue a service letter and advise its customers of available options to prevent propulsion from altering significantly when transferring control.
Analysis
The purpose of the analysis is to determine the contributory causes and circumstances of the accident as a basis for making recommendations to prevent
similar accidents occurring in the future.
Kirkella collided with Shovette due to the propeller pitch increasing after propulsion control was passed from the bridge to the engine control room. The vessel had no established procedures for the transfer of propulsion control and the crew had made assumptions based on local practices. The analysis will examine the factors influencing the loss of control of the propulsion system and other circumstances leading to the collision.
Propulsion control change
After Kirkella’s crew had conducted the engine maintenance at sea, the ECR pitch control lever being left at full ahead did not present any problem, until control was passed back to the ECR once the vessel was secured alongside. When the master requested that the ECR took control of the propulsion using the system panel there was no telephone communication with the 1/E, which could have focused their actions. Certainly, a telephone call would have required the 1/E to
leave their chair at the computer and look directly at the propulsion control screen.
There was no procedure in place to ensure that confirmation of pitch lever positions was communicated before control was handed over. Changing control station was a routine matter and the bridge team had developed a process of zeroing the bridge stations’ levers before control changeover, but this was
done with people in sight and hearing of one another, or by one person changing control, thus minimising the chance of lever mismatch. However, the ECR was
remote from the bridge and, although the system display indicated the propeller pitch setting, it did not provide an audible or overt visual alert to highlight when the bridge and ECR levers were mismatched. Consequently, without communication between the two control stations, neither was fully aware of what the other was doing and there was no procedure to ensure that lever matching occurred.
Conclusions
- The engine control room pitch control lever had been left in the ‘full ahead’ position following engine maintenance conducted while the vessel was at sea.
- Kirkella’s engineer accepted control without checking that the pitch control lever was set at zero. With no interlocks to prevent changeover with mismatched levers, control was taken at the ECR control station with its pitch control lever at ‘full ahead’ and the propeller pitch increased to 85% before the master pressed the emergency declutch button.
- There was no onboard procedure for transfer of propulsion control and training requirements for its use had been omitted from Kirkella’s safety management system.
- As fitted to Kirkella, the Rolls-Royce Helicon-X3 propulsion control system did not align to the standard of UR M43.12, which required a means to prevent significant alteration of the propelling thrust when transferring control.
- DNV’s class requirement addressing the standard in UR M43.12 introduced ambiguity, which in turn allowed the Rolls-Royce Helicon-X3 propulsion control system to be approved for use in Kirkella.
Other safety issues directly contributing to the accident
- Kirkella’s crew did not realise that the propeller pitch had increased until the vessel moved forward.
- The increase in pitch accelerated Kirkella forward and parted several mooring lines, which allowed it to continue the vessel’s movement along the quay until it collided with Shovette.
- It is likely that the effects of fatigue after a long shift coupled with the absence of a robust procedure led to the engineer paying insufficient attention to the change of propulsion control to the ECR.
Actions taken
The MAIB has issued a safety flyer to the shipping industry (Annex A).
- Introduced a new requirement to Kirkella’s pre-arrival checklist, requiring verbal confirmation that pitch controls are set to zero before changing control between stations.
- Requested that Kongsberg modify the control system to prevent reoccurrence.
Recommendations
Det Norske Veritas is recommended to:
2024/111 Propose to the International Association of Classification Societies that Unified Requirement M43.12 is reviewed to clarify its intent.
2024/112 Inform its customers that the Rolls-Royce Helicon-X3 system might allow remote control station changeover with mismatched levers and suggest that
the manufacturer be contacted for advice.
Kongsberg Maritime is recommended to:
2024/113 Issue a service letter to its customers advising that the Rolls-Royce Helicon-X3 system remote control changeover process can allow mismatching
of levers resulting in the propelling thrust altering significantly, and advise them of methods of operation and/or rectification should these be requested.
