The Aratere Grounding: Safety Culture, BRM, and the Risks of Procedural Drift

The 2024 grounding of the Interislander ferry Aratere in Picton Harbour attracted significant public attention across New Zealand and has become one of the country’s most widely discussed maritime incidents in recent years. While the grounding fortunately resulted in no loss of life or major pollution, the subsequent investigations, prosecution, and industry commentary have highlighted several important safety lessons for the wider maritime sector.

The findings from the Transport Accident Investigation Commission (TAIC), alongside the prosecution undertaken by Maritime New Zealand, highlight several recurring themes familiar to anyone involved in Bridge Resource Management (BRM), human factors, and operational assurance.

This was not simply a technical failure. It was an operational systems failure involving procedural drift, inconsistent implementation of navigation practices, gaps in assurance, degraded shared situational awareness, and a gradual normalisation away from established safe operating standards.

The grounding serves as a reminder that modern maritime incidents rarely occur because of a single mistake. Instead, they are usually the culmination of multiple small deviations, latent organisational weaknesses, and degraded safety barriers aligning at the wrong moment.

The Incident

The Aratere grounded at Titoki Bay near Picton on 21 June 2024 during a scheduled sailing between Picton and Wellington. Investigations later identified that the vessel altered course toward land after an unintended execution of a turn using autopilot, while the bridge team was unable to promptly regain effective manual steering control.

Subsequent legal action resulted in KiwiRail pleading guilty to charges under sections 36 and 48 of the Health and Safety at Work Act 2015. The Wellington District Court later imposed a fine and costs following the prosecution by Maritime New Zealand.

While public attention often focuses on the immediate technical trigger of an accident, the more important safety lessons are usually found deeper within operational systems, training standards, supervision, and organisational culture.

Procedures Only Work When They Are Consistently Applied

One of the most important findings arising from the TAIC report was the observation that: “The benefits of safe navigation procedures can be lost if they are not consistently and vigorously applied on all passages.” This is an extremely important lesson for the commercial shipping industry.

Most operators already possess documented Safety Management Systems (SMS), bridge procedures, checklists, and standing orders. However, the mere existence of procedures does not guarantee operational compliance. Over time, operational shortcuts can become normalised. Informal practices develop. Briefings become abbreviated. Challenge-and-response communication deteriorates. Navigation procedures become selectively applied depending on workload, familiarity, weather conditions, or perceived operational pressure. These changes are often gradual and subtle enough that they may not be immediately recognised internally. Eventually, the “work as imagined” described within company procedures no longer reflects the “work as actually performed” onboard.

This gap between documented procedures and operational reality is one of the most significant latent risks in the maritime industry.

The Importance of Clear Bridge Team Roles

The TAIC findings also reinforced the importance of clarifying bridge team roles and responsibilities before departure.

In high workload environments such as pilotage waters, harbour departures, confined channels, and coastal navigation, ambiguity regarding who is navigating, monitoring, communicating, or operating controls can rapidly degrade situational awareness.

Effective Bridge Resource Management relies heavily upon:

• Clearly defined roles

• Shared mental models

• Closed-loop communication

• Assertive challenge culture

• Monitoring and cross-checking

• Defined transfer-of-control procedures

• Structured briefings

These are not administrative exercises. They are active safety layers designed to prevent single-point failures from escalating into an accident.

We have observed that many bridge teams unintentionally operate with informal role allocation based on habit or experience rather than structured procedural discipline. During periods of high workload, this can lead to confusion, duplicated actions, gaps in monitoring, or assumptions that another person has completed a task.

The lesson is simple: effective BRM begins before the vessel departs the berth.

A Shared Mental Model

Another important human factors lesson reinforced by this incident is the importance of maintaining a strong shared mental model within the bridge team.

A shared mental model exists when all members of the bridge team have a common understanding of the vessel’s operational status, intended manoeuvre, navigation plan, current risks, machinery configuration, and expected actions. When this alignment degrades, individuals may begin operating based on differing assumptions regarding the vessel’s position, control status, responsibilities, or contingency actions, significantly increasing the risk of error escalation.

One highly effective BRM communication technique used to support shared mental models is the “Plan – Reason – Outcome” method.

For example:

“I plan to reduce speed due to the upcoming speed restriction area, and I am to reduce to 7 - 8knots.

This simple structure provides far greater situational awareness to the wider bridge team than a command alone, such as “I'll slow down” or “I'll reduce speed.” It allows other team members to understand not only what is happening, but why it is happening and what result is expected. Importantly, clearly communicating the expected outcome creates significantly more opportunity for monitoring, cross-checking, and intervention. If the anticipated outcome does not occur — for example, the vessel does not respond as expected, the speed does not reduce, or the manoeuvre develops differently from the plan — the bridge team is far more likely to recognise the deviation early and challenge it before it escalates into an incident.

This style of communication strengthens situational awareness, improves anticipation, takes out the 'guesswork', and supports a more proactive challenge-and-response culture onboard. In high-workload or dynamic navigational environments, these seemingly small communication techniques can become critical safety barriers.

Navigational Briefings Are More Than a Checklist Exercise

The grounding also reinforces the importance of comprehensive navigational briefings. Effective briefings are one of the best opportunities to create a shared mental model across the bridge team.

A structured briefing should ensure the team collectively understands:

• The intended manoeuvre or passage

• Critical points and hazards

• Trigger points for intervention

• Expected traffic

• Environmental conditions

• Machinery configuration

• Transfer-of-control arrangements

• Safety limits and abort criteria

• Contingency actions

When properly conducted, briefings significantly improve team anticipation, workload management, and situational awareness. Conversely, poor or rushed briefings can result in bridge team members operating with differing assumptions regarding the vessel’s intended actions, safety margins, or operational priorities.

Audits and Assessments Reveal Procedural Drift

TAIC observed that assessments and audits are “sampling tools” that may not capture every issue, but when conducted regularly, they can identify weaknesses in the implementation of procedures. This is particularly important in maritime operations because procedural drift rarely occurs suddenly. Instead, organisations gradually move away from best practice over time through operational complacency, external pressure, staffing challenges or reduced supervisory oversight. One of the greatest benefits of external BRM assessments and navigation audits is their ability to identify procedural drift, normalised deviation, and latent operational risk that can become difficult for organisations to recognise internally over time.

One of the recurring findings during independent BRM and navigation assessments across the industry is that procedures frequently exist on paper, but operational practice onboard has evolved differently. This does not necessarily indicate negligence or poor intent. More commonly, it reflects the realities of operational adaptation over time. However, without periodic external observation and assurance, these adaptations can slowly erode safety margins.

It is likely that if the annual safe navigation assessment programme referenced in the investigation had been consistently implemented, operational practices onboard may have remained more closely aligned with the procedures prescribed within the SMS. The absence of regular audits or structured assessment programmes for safe navigation procedures can itself become an indicator of gradual normalisation away from established best practice.

Shoreside Support Is Critical

Another key finding from the report was the importance of proactive shoreside support for safe navigation procedures and practices. A safe navigation culture cannot exist solely onboard.

Bridge teams operate within a wider organisational system that includes:

• Shore management

• Training departments

• Technical management

• Operational leadership

• Audit and assurance systems

• SMS governance

• Resource allocation

If standards are not actively reinforced from shore, procedural compliance can gradually become inconsistent between vessels and crews.. Strong shoreside engagement is essential to maintaining procedural discipline, standardisation, and continuous improvement. This includes:

• Regular operational audits

• External BRM & Navigation assessments

• Simulator-based training

• Human factors training

• Trend monitoring

• Leadership engagement with onboard teams

Importantly, assurance activities should not be viewed as punitive exercises. Their value lies in identifying latent risk before it contributes to an incident.

Independent Navigation Assessment and Operational Assurance

Following the Aratere grounding, KiwiRail has engaged Voyager Marine Solutions to assist with independent navigation assessment and operational assurance activities across its ferry operation. The purpose of these assessments is not simply procedural compliance, but to provide the operator with greater visibility of how navigational procedures, Bridge Resource Management principles, communication practices, and operational controls are being implemented onboard in day-to-day operations. Independent assessments can provide valuable insight into procedural drift, human factors trends, operational strengths, and opportunities for improvement that may not always be visible through internal systems alone. Importantly, this type of proactive operational assurance helps strengthen the connection between shoreside management, documented SMS procedures, and the realities of frontline vessel operations.

The Industry-Wide Lesson

The Aratere grounding should not be viewed as an isolated event relevant only to one operator. The safety themes identified are applicable across the entire commercial maritime sector, including ferries, pilotage operations, coastal shipping, offshore support vessels, fishing fleets, and domestic operators.

Most maritime accidents share common contributing factors:

• Normalisation of deviation

• Weak procedural compliance

• Reduced challenge culture

• Inadequate briefings

• Ambiguous role allocation

• Loss of shared mental models

• Inconsistent monitoring

• Poor organisational assurance

• Gradual erosion of safety barriers

  
  

The industry must continue shifting away from viewing incidents as isolated “human errors” and instead examine the operational systems, organisational influences, and human factors conditions that allow errors to develop into accidents.

The strongest safety cultures are not those that never experience mistakes. They are the organisations that continuously monitor operational reality, identify drift early, encourage challenge and feedback, and actively strengthen safety barriers before an incident occurs. The lessons from the Aratere grounding are therefore not simply about one vessel or one operator. They are a reminder to the wider maritime industry that safe navigation is not maintained through procedures alone, but through active leadership, continual assessment, effective communication, and a culture that refuses to allow poor practices to become normal.

References

• TAIC Inquiry – MO-2024-204 - Passenger and freight ferry Aratere Grounding Titoki Bay, Picton 21 June 2024

• Maritime NZ – KiwiRail sentenced over 2024 grounding of Aratere

• Dawson & Associates – Maritime New Zealand prosecutes KiwiRail for 2024 Aratere grounding

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O'Shea is a Maritime Consultant, Examiner, and Master Mariner based in Nelson, New Zealand. With over 15 years at sea aboard passenger ships, he has sailed to more than 90 countries. As the Director of Voyager Marine Solutions, he provides expert advice to the Maritime Industry, prepares and examines maritime students, and offers expert-led courses and mentoring. O’Shea combines real-world experience with a passion for teaching the next generation of seafarers.

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