Workload distractions lead to a high-speed collision
As a Crew Transfer Vessel (CTV) was returning to port at high speed, the master became distracted by a lengthy radio conversation and did not notice that the vessel had been pushed off course by the tide. It collided with a wind turbine tower at speed, causing significant damage to the vessel. The weather and visibility were good. As is common for vessels of this length, only the master was on the bridge; nobody else was keeping a lookout during the radio exchange.
Unfortunately, this is not an isolated incident: CHIRP is aware of several incidents where vessels collided with charted objects when the sole person on the bridge became distracted by workload.
Single bridge manning is common, particularly on small to medium-sized vessels by day in good visibility. However, manning requirements must always be informed by rigorous risk assessment. In the case of single bridge manning, extra care should be taken to ensure that the risks of workload, fatigue, distractions and other factors are adequately reduced to as low as reasonably practicable. The routine nature of this type of operation can lead to low mental arousal and risk distraction. This ‘risk normalisation’ reduces concern and can lead to overconfidence.
CHIRP was unsure if the ECDIS was working and correctly configured and could not determine from the report if any warning was sounded or heard.
Consideration should be given to increasing the number of lookouts during high-speed transit operations. Utilise your crew to highlight perceived hazards in the wind farm zones and use all navigational aids to assess the risks, especially on the chart plotter (alarms for off-track limits/cross-track error and radar guard zones).
Management should consider conducting a thorough risk assessment for vessels under their management using an independent auditor to determine the risks and set appropriate levels of manning for critical stages of a CTV operation.
Key Issues relating to this report
Situational Awareness – The master did not notice that the CTV had drifted off track. The offshore sector is a challenging and busy environment. What steps does your company take to ensure that this incident could not happen?
Capability – Is the resource capability adequate to ensure that safe navigational capability is maintained? The wind farm industry is relatively new, and an assessment of the risks associated with maintaining and servicing the wind turbines should be considered for review.
Distractions – Maintaining focus on a repetitive job is challenging. Having a lookout in place changes the dynamic interaction on the bridge, which can lead to a greater focus on hazard awareness.