Summary
On 3 December 2015, a Panama registered pure car Carrier City of Rotterdam collided with the Danish registered ro-ro ferry Primula Seaways on the River Humber, UK. Both the vessels were damaged but made their way to Immingham without assistance.
The MAIB investigation identified that the outbound City of Rotterdam had been set to the northern side of the navigable channel and into the path of the inbound ferry, but this had not been corrected because the pilot on board had become disoriented after looking through an off-axis window on the semi-circular shaped bridge.
The car carrier was of an unconventional design and his disorientation was due to ‘relative motion illusion’, which caused the pilot to think that the vessel was travelling in the direction in which he was looking. Consequently, the pilot’s actions, which were designed to manoeuvre the car carrier towards the south side of the channel, were ineffective.
City of Rotterdam – bridge (from port side)
Primula Seaways – bridge
That the pilot’s error was allowed to escalate the developing close quarter’s situation to the point of collision was due to intervention by City of Rotterdam’s master was too late, and the challenges to the pilot’s actions by Primula Seaways’ bridge team and the Humber Vessel Traffic Service being insufficiently robust. Although Primula Seaways started to reduce speed about 2 minutes before the collision, a more substantial reduction in speed was warranted.
Following the accident, and an early MAIB recommendation, action has been taken by Fairmont Shipping (Canada) Limited, City of Rotterdam’s managers, to reduce the likelihood of relative motion illusion and to improve the bridge resource management of its deck officers. Action has also been taken by Associated British Ports, the harbour authority for the River Humber, to confirm the competency of the pilot and the suitability of Primula Seaways’ master to hold a pilotage exemption certificate.
Bureau Veritas, City of Rotterdam’s classification society, has been recommended to propose measures to the International Association of Classification Societies that are aimed at raising the awareness of relative motion illusion and promoting the need for naval architects and shipbuilders to adhere to internationally accepted ergonomic principles for bridge design.
Damage
Primula Seaways suffered damage to its bow above the waterline. City of Rotterdam’s bow was damaged in way of the forward mooring deck, the forward hydraulic room, and car decks 5 and 6. The port side bilge keel and plating was also depressed and damaged, which resulted in water ingress to number 4 port ballast tank. The vessels were surveyed by classification society and Maritime and Coastguard Agency (MCA) surveyors. Following temporary repairs in Immingham, both vessels proceeded to a ship repair yard on the River Tyne for permanent repair. The estimated cost of returning Primula Seaways to service was
US$3 million. City of Rotterdam spent 2 months in dry dock, but the cost of the vessel’s repair was not disclosed.
Primula Seaways damage
Fortunately, during the incident, no crew members were injured and no pollution to the environment was reported.
Action Taken
- The importance of emphasising to the crew and embarked pilots the risk of spatial distortion occurring on these bridges.
- The increased risk of distorted spatial awareness when standing away from the centreline or a navigation station, including when using the fixed VHF radios.
- The need to monitor pilots’ actions at all times and to challenge when appropriate.
City of Rotterdam damage
Conclusions
- The collision stemmed from City of Rotterdam being set to the northern side of the Bull Channel by the wind and the tidal stream followed by the distortion of its pilot’s spatial awareness due to a ‘relative motion illusion’.
- City of Rotterdam’s pilot’s relative motion illusion deceived him into thinking that his view from the window above the starboard VHF radio, which was 33° off the vessel’s centreline axis, was the vessel’s direction of travel.
- As it was dark, the inward slope of the window removed all objects in the pilot’s periphery, and there were no visual clues such as a forward structure or bow tip, the illusion would have been compelling.
- The pilot’s ability to reconcile the headings he had ordered with his perceived direction of travel was probably hindered by further psychological effects of the relative motion illusion, such as the cognitive costs of transferring between different frames of reference.
- Soon after the City of Rotterdam entered the main navigation channel, the master and the third officer left the responsibility for the vessel’s safe passage predominantly to the pilot.
- City of Rotterdam’s master and third officer did not challenge the pilot’s actions despite concern at the vessel’s position being expressed by Primula Seaways and the VTS. The master’s intervention, 14 seconds before the collision, was far too late to be effective.
- City of Rotterdam’s bridge team’s over reliance on the pilot, and its lack of effective monitoring of the vessel’s progress, were evidence of ineffective bridge resource management.
- Although Primula Seaways’ engines were reduced to ‘half ahead’ 2 minutes before the collision, a more substantial reduction of speed was warranted in view of the doubt concerning City of Rotterdam’s movement.
- The VTS intervention at 2038 could have been more effective in alerting the bridge teams on board both vessels to its concerns had it been prefixed with a ‘warning’ message marker and it had not referred to the pilot by name.
- The location of the VHF radios by the off-axis windows on board City of Rotterdam increased the potential for relative motion illusion.
- The potential for relative motion illusion was unforeseen and therefore not taken into account during the design of City of St Petersburg and City of Rotterdam.
- Stricter adherence to the ergonomic principles of bridge design detailed in SOLAS V/15 would reduce the likelihood of human error. Therefore, the need for an IACS UI on the interpretation of the ergonomic principles of bridge design warrants reconsideration.
Recommendations
Propose to the International Association of Classification Societies that Recommendation 95 “Recommendation for the Application of SOLAS Regulation V/15 Bridge Design, Equipment Arrangement and Procedures (BDEAP)” is revised to:
- Improve the definition of conning position(s), taking into account the equipment that is required to be at, viewable from, and convenient to the position.
- Raise the awareness of the dangers of navigating from off-axis windows and the effect of relative motion illusion.
Propose to the International Association of Classification Societies that the status of Recommendation 95 is raised to a Unified Interpretation.
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Source: MAIB
